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ThinkPad Helix Lenovo ThinkPad Helix refers to two generations of 2-in-1 convertible tablets that can be used as both a conventional ultrabook and a tablet computer. The first-generation Helix was announced at the 2013 International CES and was released on 21 May 2013. A second-generation Helix came out in 2014. History First generation In March 2013, Lenovo said that the ThinkPad Helix would launch in April in the United States. Launch dates in other countries will vary. The Helix was announced at the 2013 International CES. Lenovo touts the device as a “high performance Ultrabook with a detachable Windows 8 tablet.” The starting price for the base model Helix is expected to be $1,499. Second generation The ThinkPad Helix II was released in October 2014. It is an Ultrabook-class convertible laptop based on the Intel Core M processor. The Helix II uses a vapor chamber with no moving parts instead of fans for cooling, achieving a significant noise reduction. It is both thinner and lighter than its predecessor at .38 inches thick and weighing 1.8 pounds. Features Design The Helix serves as a conventional notebook computer but uses a "rip and flip" design that allows the user to detach the display and then replace it facing in a different direction. Also, as all essential processing hardware is contained in the display assembly and it has multitouch capability, the monitor can be used as a standalone tablet computer. The Helix features include Gorilla Glass, stylus-based input, and Intel vPro hardware-based security features, and is designed to appeal to business users. The Helix makes use of a refined version of the ThinkPad trackpoint. The five mechanical buttons featured on most ThinkPad trackpoints have been replaced with a fixed glass touchpad. The included pressure-sensitive stylus is from Wacom and fits into a dedicated slot in the tablet portion of the device. Specifications and performance The Helix has an 11.6-inch 1080p IPS display that has ten-point capacitive multi-touch capability. At 400 nits the Helix's display is the brightest available among ThinkPad models. Connectors for mini-HDMI and mini-Display Port support graphics output. A five-megapixel rear camera and a two-megapixel front-facing camera are mounted on the display. The Helix comes standard with an Intel 3rd generation Core i5 processor, but can be upgraded to a Core i7 processor. On launch, the i7 upgrade for a convertible tablet was unique within its class. A SSD is used for HD storage. Fans are situated where the keyboard dock meets the tablet. This allows the Helix's processor to take advantage of Intel chipset capabilities to regulate clock speeds in relation to heat distribution. The Helix's power management software controls the speed of the processor to ensure that battery life is not adversely affected. The battery in the Helix's tablet section is advertised as providing five hours of use. Docking the tablet with the keyboard extends battery life by an advertised additional five hours. The Helix is equipped with WiFi, NFC, and a cellular modem with support for 3G and 4G LTE SIM cards as an option. A LAN port is offered for wired networking capability. The entire device weighs almost four pounds and the tablet portion weighs less than two pounds. Reviews In a review published in Forbes Jason Evangelho wrote, "The first laptop I owned was a ThinkPad T20, and the next one may very likely be the ThinkPad Helix which Lenovo unveiled at CES 2013. In a sea of touch-inspired Windows 8 hardware, it’s the first ultrabook convertible with a form factor that gets everything right. The first batch of Windows 8 ultrabooks get high marks for their inspired designs, but aren’t quite flexible enough to truly be BYOD (Bring Your Own Device) solutions. Lenovo’s own IdeaPad Yoga came close, but the sensation of feeling the keyboard underneath your fingers when transformed into tablet mode was slightly jarring. Dell‘s XPS 12 solved that problem with its clever rotating hinge design, but I wanted the ability to remove the tablet display entirely from both of those products." In a review published in CNET Vincent Chang wrote, "It gets worse once you add the dock, with the weight of the Helix increasing to 1.67kg with the accessory. That's not exactly light for a 11.6-inch device when you can find slimmer 13.3-inch Ultrabooks, such as the Acer Aspire S7. Of course, the Helix is a hybrid device that can be used in more ways than one--you aren't saddled with the keyboard like a laptop." Chang concluded, "With a starting price of US$1,499, the ThinkPad Helix is pretty expensive, even for Ultrabook convertibles. However, its business slant means that companies, which can afford the premium price for the extra security and enterprise features, are most likely the ones to purchase the Helix." In another review published by CNET editors wrote, "There's a lot to like about the Lenovo ThinkPad Helix. The engineers at Lenovo have come up with the best detachable docking hybrid system I've seen (although there may be no solution to the fact that these docking hinges are just inherently clunky). It feels sturdier and more reliable than many other hybrids, and the double battery system offers flexibility for longer work days." In an early review for TechRadar Alex Roth wrote, "The Thinkpad Helix is exactly the kind of product Lenovo is known for: sturdy, versatile and designed for productivity to the point where it might [be] too niche for the average consumer. A lot of convertible tablet/ultrabooks look like just that, a tablet jammed into a keyboard stand. Not the Helix, all put together, it looks very much like one piece of equipment. As just a tablet, it's a great size and weight, making it easy to hold." However, by the time of its release, that opinion had soured somewhat: "When we first saw the Lenovo ThinkPad Helix at CES 2013, it had us really excited. We thought Lenovo had finally cracked the convertible ultrabook, a design we've never been totally sold on. But that was months ago, in a pre-Haswell, 12-hour MacBook Air world. The ThinkPad Helix is better late than never, but its $1,679 price point makes it tough to recommend." References Lenovo laptops Tablet computers Convertible laptops Lenovo Ultrabooks 2-in-1 PCs Helix

laptop Form Factor and Weight

Webbook Webbooks (a portmanteau of web and notebook computer) are a class of laptop computers such as the litl, Elonex and Coxion webbook computers. The word may also refer to books that are available in HTML on the web. and the NIST Chemistry WebBook, a scientific database of chemical properties maintained by the National Institute of Standards and Technology. The word may also refer to The WebBook Company of Birmingham, Michigan, which planned to deliver a Net computer based on the PSC1000 RISC processor (then and now also known as the ShBoom) designed by Charles H. Moore. Legal issues was filed by Robert & Colleen Kell of Austin, Texas on 18 November 2008. The application was deemed abandoned on Aug. 23, 2009. See also Netbook Tablet computer References Mobile computers Electronic publishing

laptop Form Factor and Weight

JXD P861 The JXD P861 is a 7-inch Android tablet PC produced by JXD released in 2013. Features In addition to its 7-inch, five-point capacitive touch screen, the P861 features a 0.3 megapixel front camera, and a 0.3 megapixel rear camera. It is equipped with a MTKB312, dual core, 1.3 GHz chipset. The system runs Android 4.2 as an operating system. The memory of this unit is 512 MB RAM plus 4 GB ROM and it supports WIFI. The battery capacity is up to 2500mAh. Revisions About a month later after the release of JXD P861, JXD released JXD P1000M which was equipped with a 7-inch 5-point 800*480 touchscreen, MTK6572, Dual Core, 1.2 GHz chipset, the battery capacity was up to 3650 mAh. Later, the JXD P1000S was released in the Chinese market, it was equipped with an internal 2100mAh plus a removable 1960 mAh battery. See also JXD HTC Flyer References External links JXD official website JXD Product Information Android (operating system) software Smartphones Tablet computers

laptop Form Factor and Weight

Mechanical computer A mechanical computer is a computer built from mechanical components such as levers and gears rather than electronic components. The most common examples are adding machines and mechanical counters, which use the turning of gears to increment output displays. More complex examples could carry out multiplication and division—Friden used a moving head which paused at each column—and even differential analysis. One model, the Ascota 170 accounting macine sold in the 1960s calculated square roots. Mechanical computers can be either analog, using smooth mechanisms such as curved plates or slide rules for computations; or digital, which use gears. Mechanical computers reached their zenith during World War II, when they formed the basis of complex bombsights including the Norden, as well as the similar devices for ship computations such as the US Torpedo Data Computer or British Admiralty Fire Control Table. Noteworthy are mechanical flight instruments for early spacecraft, which provided their computed output not in the form of digits, but through the displacements of indicator surfaces. From Yuri Gagarin's first manned spaceflight until 2002, every manned Soviet and Russian spacecraft Vostok, Voskhod and Soyuz was equipped with a Globus instrument showing the apparent movement of the Earth under the spacecraft through the displacement of a miniature terrestrial globe, plus latitude and longitude indicators. Mechanical computers continued to be used into the 1960s, but were quickly replaced by electronic calculators, which—with cathode-ray tube output—emerged in the mid-1960s. The evolution culminated in the 1970s with the introduction of inexpensive handheld electronic calculators. The use of mechanical computers declined in the 1970s and was rare by the 1980s. In 2016, NASA announced that its Automaton Rover for Extreme Environments program would use a mechanical computer to operate in the harsh environmental conditions found on Venus. Examples Antikythera mechanism, c. 100 BC – A mechanical astronomical clock. Cosmic Engine, 1092 – Su Song's hydro-mechanical astronomical clock tower invented during the Song dynasty, which featured the use of an early escapement mechanism applied to clockwork. Castle clock, 1206 – Al-Jazari's castle clock, a hydropowered mechanical astronomical clock, was the earliest programmable analog computer. Pascaline, 1642 – Blaise Pascal's arithmetic machine primarily intended as an adding machine which could add and subtract two numbers directly, as well as multiply and divide by repetition. Stepped Reckoner, 1672 – Gottfried Wilhelm Leibniz's mechanical calculator that could add, subtract, multiply, and divide. Difference Engine, 1822 – Charles Babbage's mechanical device to calculate polynomials. Analytical Engine, 1837 – A later Charles Babbage device that could be said to encapsulate most of the elements of modern computers. Odhner Arithmometer, 1873 - W. T. Odhner's calculator who had millions of clones manufactured until the 1970s. Ball-and-disk integrator, 1886 – William Thomson used it in his Harmonic Analyser to measure tide heights by calculating coefficients of a Fourier series. Percy Ludgate's 1909 Analytical Machine – The 2nd of only two mechanical Analytical Engines ever designed. Marchant Calculator, 1918 – Most advanced of the mechanical calculators. The key design was by Carl Friden. István Juhász Gamma-Juhász (early 1930s) Kerrison Predictor ("late 1930s"?) Z1, 1938 (ready in 1941) – Konrad Zuse's mechanical calculator (although part imprecisions hindered its function) Mark I Fire Control Computer, deployed by the United States Navy during World War II (1939 to 1945) and up to 1969 or later. Curta calculator, 1948 Moniac, 1949 – An analog computer used to model or simulate the UK economy. Voskhod Spacecraft "Globus" IMP navigation instrument, early 1960s Digi-Comp I, 1963 – An educational 3-bit digital computer Digi-Comp II, mid 1960s – A rolling ball digital computer Automaton – Mechanical devices that, in some cases, can store data and perform calculations, and perform other complicated tasks. Turing Tumble, 2017– An educational Turing-complete computer partially inspired by the Digi-Comp II Electro-mechanical computers Early electrically powered computers constructed from switches and relay logic rather than vacuum tubes (thermionic valves) or transistors (from which later electronic computers were constructed) are classified as electro-mechanical computers. These varied greatly in design and capabilities, with some later units capable of floating point arithmetic. Some relay-based computers remained in service after the development of vacuum-tube computers, where their slower speed was compensated for by good reliability. Some models were built as duplicate processors to detect errors, or could detect errors and retry the instruction. A few models were sold commercially with multiple units produced, but many designs were experimental one-off productions. See also Analog computer Billiard-ball computer Domino computer History of computing hardware List of pioneers in computer science Mechanical calculator Tide-Predicting Machine No. 2 Turing completeness References External links Electro-mechanical Harwell computer in action Electro-mechanical computers

laptop Form Factor and Weight

Dynabook Satellite The Satellite was a line of laptops manufactured by Toshiba's computer subsidiary now known as Dynabook Inc. Models in the Satellite family varied greatly—from entry-level models sold to consumers at major retailers to full-fledged business laptops sold through enterprise channels. The latter were marketed as the Satellite Pro. The earliest models in the series, introduced in the early 1990s, were one of the first to directly compete against IBM's ThinkPad line. The consumer Satellite series later competed against Acer's Aspire, Dell's Inspiron and XPS laptops, HP's Pavilion, and Lenovo's IdeaPad. Toshiba discontinued the Satellite in 2016 after they left the computer market that year. In 2019, Sharp Corporation bought majority interest of Toshiba's computer subsidiary, later buying the remainder of Toshiba's shares in 2020, and renamed the company to Dynabook Inc. That year, Dynabook resurrected the Satellite Pro series, positioning it between their consumer E series and their business Tecra (the latter also formerly manufactured by Toshiba). History The early models did not come with an internal CD-ROM drive, but these soon appeared as mobile technology progressed. Such models can link up with an external CD-ROM drive through the parallel port on the rear (since USB ports came later as well). Some Satellites also lacked an internal floppy disk drive, but a port on the side allowed the use of a proprietary external module for such. These machines tended to be smaller in physical size than their contemporaries. A Toshiba Satellite personal computer was used to send the first email ever sent by President Bill Clinton during his presidency. The email was sent using the personal computer of White House Medical Unit Emergency Physician Dr. Robert G. Darling, and was sent to astronaut John Glenn as he was aboard the Space Shuttle Discovery. Notable models included the Satellite 5005-S507 which was the first to ship with NVIDIA GeForce 4 440 Go GPU and cost $1,999. The Satellite 5105-S607 was the first laptop with cPad technology and cost $2,499. The Satellite 5205-S703 was the first laptop with built-in DVD-R/RW drive and cost $2,699. Sharp Corporation obtained 80.1% of Toshiba's computer subsidiary in October 2018. In April 2019, Sharp renamed the subsidiary Dynabook Inc.. In 2020, Toshiba sold their remaining shares to Sharp. Sharp resurrected the Satellite Pro series that year. Satellite models Numeric The Satellite line was introduced in 1992 with the T1800 and T1850 models, the T1800C and T1850C variants of which were one of the first notebooks with passive-matrix color LCDs. Succeeding entries in the line followed this naming scheme, such as the Satellite T1900, T2110CS and T2130CS. Beginning with the barebones 100CS and 100CT in February 1996, Toshiba began using only numbers to name their Satellites, a convention which continued until 2003 with the introduction of the Satellite A series. Lettered Toshiba began using letter prefixes to differentiate its concurrent series of Satellite laptops. These included the A series; the C series; the E series; the L series; the M series; the P series; the R series; the S series; the T series; the U series; and the W series. CNET wrote in 2011 that "Toshiba may not run out of new product lines until it runs out of letters". A series The A series was Toshiba's first premium consumer line of Satellite laptops. Introduced with the A10 and A20 models in 2003, the A series originally targeted high school and college students and workers of small offices and home offices, before becoming a premium line by the late 2000s. The A series was succeeded by the P series in 2011. C series The C series was Toshiba's budget consumer line of Satellite laptops. Screen sizes on the C series ranged between 14 and 17 in diagonally; the laptops were offered with Intel or AMD processors. E series The 2010s-issue E-series Satellites were Best Buy-exclusive midrange consumer models. L series The L series Satellites were Toshiba's mainstream consumer line of Satellite laptops. The first models of the L series came out in 2005. The 2010s-issue L series was priced just above of the C series and included similar features but featured improved keyboards, trackpads, and speakers, USB 3.0 ports, and Core i7 processor configurations. Toshiba targeted the L series at students. M series, U series The M and U series Satellites were marketed as multimedia-oriented machines, powerful enough for casual gaming and video playback while still being lightweight enough to be easily mobile. Toshiba marketed the U series as the more stylish of the two. P series The P series was Toshiba's second premium consumer line of Satellite laptops. Introduced in 2003, it later eclipsed the premium A series. The first entry in the series, the P25, was one of the first laptops to feature a widescreen 17-in LCD; it was also one of the first laptops to feature an internal DVD±RW drive. P series models introduced in 2012 were priced at US$800, $100 higher than their midrange S series counterparts. R series The R series was a convertible laptop in the Satellite line released from 2005 to 2006. It comprised the R10, R15, R20, and R25; all featured a swivel-hinge display that the user could rotate 180 degrees to cover the keyboard and use the laptops with a stylus. A non-convertible midrange entry, the R845, was released in 2011. S series The S series was Toshiba's midrange line of Satellite laptops introduced in 2012. It was positioned above their mainstream L series but below the premium P range. Features included Nvidia GeForce graphics processing units, Harman Kardon speakers, optional touchscreen displays and optional backlit keyboards; it was the lowest price entry of the Satellite family to offer discrete graphics. Displays ranged from 14 to 17.3 inches diagonally in size. T series The T series was Toshiba's line of Satellite ultrabooks. Satellite Click, Satellite Radius The Satellite Click and Satellite Radius were convertible laptops introduced in 2013 and 2014 respectively. The Satellite Radius had a folding hinge, while the Satellite Click's display was entirely detachable. References External links (Archive) of Toshiba Satellite Official website (in Japan) of Toshiba Satellite (dynabook.com) (Archive) of Toshiba Satellite Pro Consumer electronics brands Discontinued products Satellite Ultrabooks

laptop Form Factor and Weight

IdeaPad U series The first laptop in the IdeaPad U series was the U110 launched in 2008 by Lenovo. Showcased at CES 2008, the laptop also launched the IdeaPad series itself, and received the Best of CES 2008 award. The IdeaPad U series was a line of Lenovo's consumer line of laptops, combining Lenovo's traditional engineering with design changes that were significantly different from ThinkPad products. 2014 U530 The IdeaPad U530 has a low-voltage 4th-Gen Core i7-4510U processor, a 2 GB Nvidia Geforce GT 730M graphics card, a 1080p display with a multi-touch pane. It includes Windows 8.1, 8 GB RAM and a 1 TB hybrid hard drive with a 16 GB mSATA SSD, 3 USB ports (one USB 3.0), HDMI and a multi-card reader, dual-band 802.11bgn, and as well as Bluetooth 4.0. The machine is 5.07 lbs, 0.86 inches thick, and has between six and ten hours of battery life depending on usage. Other features include its backlit keyboard, Stereo speakers with Dolby Home Theater, and motion control. 2013 The 2013 update adopted fourth generation Intel chips and saw the switch to Windows 8. Models launched that year included the IdeaPad U330p (Intel i5-4200U) and IdeaPad U430 Touch. A refresh of the 2012 model, the IdeaPad U410 was also released, with the touch enabled IdeaPad U410 Touch (Intel i5-3337U). 2012 U310 U410 2011 The IdeaPad U-series laptops released by Lenovo in 2011 were the U300s, U400, U550 and U460. U300s The U300s was described by Engadget as being "pared-down and tasteful". It was compared to the Macbook Air in terms of design since, like the Air, it was made from a single sheet of aluminum. Also, like the Air, the U300s was indicated to be susceptible to scratches, despite the fact that the metal had been sandblasted and anodized. Engadget also criticized the U300s for the lack of a memory card slot, stating that, "it's the only Ultrabook we know of that doesn't have a memory card slot." The keyboard on the laptop received praise and was described as being sturdy and comfortable to type on. The glass touchpad was also received positively, with the reviewer stating that, "it has the best touchpad of any of the new Ultrabooks we've tested." An innovation in the laptop, as described by Laptop Magazine, was the solid base plate. Air intake was designed to be through the keyboard, with two vents on the side handling expulsion of air. The laptop's display screen was received positively, with the reviewer saying that, "we could make out the lint on Kermit the Frog in a 1080p Muppets trailer, and the entire cast was an explosion of colors." The laptop also offered Intel Wireless Display (WiDi) technology, allowing users to stream video from their laptops to an HDTV. The laptop also offered faster boot and wake-from-sleep times of 34 seconds and 4 seconds respectively. Processor performance was also indicated to be positive, with PCMark Vantage score of 10,174, which was double the average for ultraportables. Graphical capabilities were not received positively, with the U300s scoring 3,398 in 3DMark06. When used to play World of Warcraft, the U300s offered 31fps, with graphical settings on 'Good' and at a resolution of 1366x768. Detailed specifications of the U300s are as follows: Processor: Intel Core up to i7-2677M (2x 1.8 GHz) RAM: up to 4GB Graphics: Intel HD 3000 Storage: 1x SATA (256GB SSD) Display: 13.3" (1366x768) Wireless: Wi-Fi: 802.11 b/g/n, Bluetooth 2.1 + EDR Dimensions: 12.8 x 8.5 x 0.59 inches Weight: U400 PC Mag summed up the IdeaPad U400 by saying "The Lenovo IdeaPad U400 laptop combines solid performance with a design you won't be able to keep your hands off of." The reviewer continues by stating that the U400 was designed with mainstream users in mind, with the sandblasted aluminum chassis and glass touchpad. The design was contrasted with other laptops offered by different manufacturers. Where other, similar laptops were available in clamshell and wedge designs, the U400 laptop was flat, with protruding top and bottom lids, similar to the cover of a book. The U400 was indicated to be "well-equipped", offering Intel Core i5 processors and discrete AMD graphics. The laptop included a 14-inch screen with a maximum resolution of 1366 x 768 pixels. The features of the U400 were described as being on par with the Macbook Air and the Dell XPS 14z, such as the USB ports, a headset jack, and an Ethernet port. The only point which was indicated to be negative was the price. Engadget also reviewed the U400 positively, stating that they were "smitten with the understated design". However, the keyboard received some criticism, with the reviewer stating that the keys could have been larger, with certain keys like Tab, Shift, Backspace, and the arrow keys feeling undersized. In addition, the reviewer stated that, despite this drawback, the keyboard remained comfortable to use. The touchpad also received criticism, which Engadget stated was the result of supplier change from Synaptics to Cypress. The use of Intel Wireless Display was indicated to be a positive point, which allowed laptop users to mirror their display on a HDTV or a monitor using a special-purpose adapter. Detailed specifications of the U400 laptop are as follows: Processor: up to Intel Core i5-2430M RAM: up to 8GB Graphics: Intel HD 3000 AMD Radeon HD 6470M Display: 14" 1366x768 TN Storage: HDD 750GB 7200RPM Weight: U460 Released in June 2010, the U460 laptop offered the following specifications: Processor: up to 2.66 GHz Intel Core i5-480M RAM: up to 4GB DDR3 1066 MHz Graphics: Intel Graphics Media Accelerator HD NVIDIA GeForce 305M U550 Notebook Review indicated that while the U550 was a traditionally designed laptop with no extraordinary design features, it was extremely thin and light for a 15.6-inch notebook. The plastic used was light and of "reasonable quality". Both the palm rest area and the back of the lid did not retain fingerprints or dust. However, the glossy plastic around the screen was described as being "impossible to keep clean". The chassis and the palm rest were reported to exhibit some flex. However, pressure applied to the back of the lid did not result in ripples on the screen, which was reported to be impressive for such a thin laptop. The display hinges were also reported to be strong, since the laptop could be opened without holding down the lower half of the laptop. Both the keyboard and the touchpad received praise. The keyboard was described as having good tactile feedback with appropriate key travel. The touchpad was described as having a matte surface which was easy to use and buttons with good tactile feedback. The multi-touch features were indicated by Notebook Review to "work sporadically at best". Detailed specifications of the U550 laptop are as follows: Processor: Intel Core 2 Duo SU7300 (1.3 GHz, 3MB L2 cache, 800 MHz FSB) RAM: 4GB DDR3 Graphics: Intel GMA 4500MHD ATI Mobility Radeon HD 4330 512MB Storage: 320GB 5400RPM Wireless: Bluetooth 2.1 + EDR, wi-fi Dimensions (W x D x H): 14.8 x 9.9" x 0.9 ~ 1.2 inches 2010 The IdeaPad U-series laptops released by Lenovo in 2010 were U160 and U260. U160 and U165 The U160 was released in May 2010 in the United States and in June in Japan. It was an 11.6 inch laptop with an Intel i7 ultra-low voltage processor. The same laptop was also available with an Intel i5 processor, as a lower end version. The U165 was released at the same time, and was another 11.6 inch laptop. However, the major difference was the use of AMD processors instead of Intel. Engadget said about the U160, “The U160 is without a doubt the most powerful 11.6-inch laptop we've ever toyed with thanks to its 1.20GHz Intel Core i7-640UM processor and 4GB of RAM (the Alienware M11x comes close, but it was then powered by a Core 2 Duo processor).” However, they also added that “the U160 falls in between a standard voltage Core i3 laptop and some of the newer AMD Nile-powered ultraportables on the performance scale”. U260 The U260 notebook was received with high praise from Engadget, with special mention made of its appearance. The reviewer called the notebook “one of the most dapper and svelte laptops we've seen in a long time”. The notebook was commended for its performance with Intel i3 or i5 ultra-low voltage processors, magnesium-aluminum alloy shell, leather palm rest, and brushed glass touchpad. However, the battery life was deemed to be too low, at 3 to 3.5 hours. Engadget also commented on the appearance of the U260, saying that, “The U260 is indeed a total 180 for the company, and it's one of the most dapper and svelte laptops we've seen in a long time − there's no question about it, its magnesium-aluminum alloy shell, leather palm rest, and glass touchpad even give the newest MacBook Airs a run for their money.” 2009 The IdeaPad U-series laptops released in 2009 by Lenovo were the U350, U450p, and U150. U150 The U150 laptop was scheduled for release in November 2009 in the United States. However, as of October 2009, it was already available in Japan. LAPTOP Magazine appreciated both the design and the battery life of the laptop, while criticizing the temperature control and keyboard. Notebook Review indicated that the laptop offered portability and value with enough performance to keep most customers happy, while criticizing the build quality. Detailed specifications of the notebook are as follows: Processor: Intel Core 2 Duo SU7300 (1.30 GHz, 800 MHz FSB, 3MB L2 cache) RAM: 4GB DDR3 (1066 MHz) Storage: 1x SATA (320GB HDD 5400 RPM) Display: 11.6" (glossy, 1366x768) Graphics: Intel GMA 4500MHD Wireless: Intel 5100AGN, Bluetooth 2.1 + EDR Dimensions (inches): 11.4 x 7.5 x 0.5-1.35 Weight: Operating System: Windows 7 Home Premium 64-bit U350 The U350 was released in July 2009 to mixed reviews from different publications. LAPTOP Magazine appreciated the laptop's design and low starting price, but was disappointed by the low battery life. Computer Shopper discounted the laptop's performance but appreciated the light weight and affordable price. Stark Insider appreciated the laptop's price, performance, keyboard, display and speakers. The negative points noted were the fan noise and heat on the left palm rest. Detailed specifications of the laptop are as follows: Processor: 1.3-GHz Intel Core 2 Solo RAM: 4GB Storage: 320GB 5400RPM SATA Display: 13.3" (1366x768) Graphics: Intel GMA 4500MHD Wireless: Wi-Fi: 802.11a/b/g/n, Bluetooth 2.1 + EDR Dimensions (inches): 12.9 x 9.0 x 1.0 Weight: Operating System: Microsoft Windows Vista Home Premium (32-bit) U450p The IdeaPad U450p was launched in August 2009. TechRadar UK praised the laptop for performance, build quality, and inclusion of an optical drive. Although the review stated that “some of the chassis panels flex under moderate pressure”, it was indicated that “realistically this shouldn't prove too much of durability issue, however”. The design was also noted: instead of a glossy design, a mottled, checkered design was used instead, which did not get scratched or dirty easily. 2008 The IdeaPad U-series laptops released in 2008 by Lenovo were the U110 and U330. U110 The IdeaPad U110 was an 11.1 inch laptop, a first for Lenovo in the United States. The most striking feature of the laptop was the red top lid with a flowery pattern on it – another first for a Lenovo laptop. The keyboard was also vastly different from traditional Lenovo keyboards, with glossy keys that were set very close to each other. The advantage of the keyboard was that because of the reduced spacing, keys were far larger than those of similar sized laptop. However, the design itself and the smaller spacebar key required some getting used to, as indicated by Notebook Review. Detailed specifications of the notebook are as follows: Processor: Intel Core 2 Duo (Low Voltage) Display: 11.1" Glossy WXGA (1366x768) Graphics: Intel X3100 Storage: 1x SATA (160GB HDD or 64GB SSD) Webcam: 1.3MP Sound: two speakers, 1.5W Network: 10/100 Ethernet, Intel 4965AGN wireless, Bluetooth Battery: up to 8 hours U330 The U110 was followed by the U330 laptop in November 2008. It retained features like the touch-sensitive media controls, and facial recognition. New features included were an altered keyboard, which LAPTOP Magazine indicated was more comfortable, and switchable graphics. Detailed specifications of the notebook are as follows: Processor: 2 GHz Intel Core 2 Duo RAM: Up to 4GB Storage: 1x SATA (250GB 5400RPM), 1x Optical Drive (8x DVD R/W) Display: 13.3" (1280x800) Graphics:Intel GMA 4500MHD + ATI Mobility Radeon HD 3450 Wireless: Wi-Fi 802.11a/b/g/n Ports: 2 USB, Ethernet, FireWire, HDMI, Headphone, Microphone, Modem, VGA; 6-1 card reader, ExpressCard Dimensions (inches): 12.5 x 9.3 x 0.9 Weight: Operating System: Microsoft Windows Vista Home Premium References External links IdeaPad U Series on Lenovo.com U Computer-related introductions in 2008

laptop Form Factor and Weight

ZenBook ZenBook is a family of ultrabooks – low-bulk laptop computers – produced by Asus. The first ZenBooks were released in October 2011, and the original range of products was amended and expanded during 2012. Models range from 12-inch laptops featuring power efficient components but lacking connectivity and having only integrated graphics processors, to 15-inch laptops with discrete graphics processing units and optical disc drives. Most (though not all) ZenBooks use Intel Core ultra-low-voltage processors and Nvidia GPUs when integrated graphics are not used. Asus introduced new models with touch screens to take advantage of Windows 8 after its release in late 2012. Most models drew comparisons to the Macbook Air. The ZenBook mainly competes against computers such as Acer's Aspire, Dell's Inspiron and XPS, HP's Pavilion, HP Stream and Envy, Lenovo's IdeaPad, Samsung's Sens and Toshiba's Satellite. Asus designed the ZenBooks with brushed aluminium chassis and high rigidity, rather than plastic, the usual laptop construction material. A pattern of concentric circles on the lids is said to represent ripples in water and represent the "zen philosophy" that designers wanted to portray when creating the laptops. ZenBooks have been generally well received due to their chassis design and appearance as well as the high quality screens used in later models. However, the touchpad software was found to be erratic, particularly on the early models and some of the models received criticism for their high prices. Some models (such as the UX32) suffer from lockdown when the lithium polymer battery cell gets drained or discharged below its recommended threshold, for example if the device is left on and unattended. The result is that the charger will fail to recharge the battery even when plugged in, leaving the machine in a near-complete unresponsive off-state. The machine can often be revived by pressing the power-on key for 10 seconds, whereupon it will start recharging. Design In 2009 Asus released the UX50V, a 15-inch laptop that was focused on energy efficiency and had a thin profile. The laptop was rated poorly by reviewers as it under-performed and had mediocre battery life, despite the installed energy efficient hardware. Although not branded as one, it bore the same "UX" product code as many of the later ZenBooks and was an early foray into the ultraportable market. The ZenBook name was proposed by Asus chairman Jonney Shih to reflect the "zen philosophy" applied to the design. The chief designer, Loewy Chen, had wanted to incorporate design elements from luxury watches into his products for a long time. ZenBooks were the first opportunity to put this into practice, the crossover being achieved, he said, by "the unfolding of the laptop from the side recalling the elegance of minute and hour hand movements". The reference to watches is also reflected in the marketing of ZenBooks; Asus published design sketches overlaying an open ZenBook on a watch face, and video advertisements feature similar imagery. The concentric circles on the lid of Zenbooks were intended to look like ripples in water and to reflect "philosophical ideas such as the infinite nature of Zen thinking and self-improvement". The bodies of the ZenBooks are made of aluminium, chosen for its light weight, strength, vibration dampening, appearance and acoustic properties. Both the bodies and lids are CNC milled and brushed for appearance. Reviewers have noted the resulting superior rigidity and complimented the appearance of the ZenBook range. To preserve space, some Zenbooks use two PCBs connected by a communications ribbon so it can have ports on both sides of the device, with a heatsink and fan centred between them. In 2017, Asus debuted ScreenPad with the ZenBook Pro 15 UX580. The ScreenPad replaces the regular touchpad with a colour capactive touchscreen display. This technology was then in 2019 included in the ZenBook 13 (UX334), ZenBook 14 (UX434) and ZenBook 15 (UX534) and offered optionally on the lower end lineup of VivoBook S laptops. In 2019, as a successor the 2018's ZenBook Pro, the ZenBook Duo and ZenBook Pro Duo feature two screens – one at the regular position and the other above keyboard. This second display resulted into the move of the keyboard nearer to the chin and the touchpad to where a numberpad would be similarly to Asus' gaming ROG Zephyrus laptop. Controversy Numerous Zenbook models with resolution specifications of QHD+ (3200 × 1800) and 4K (3840 × 2160) utilize Pentile RG/BW displays, which are regarded by some as a "shady practice" and "sort of cheating". Specifications Reception The first official ZenBooks, the ZenBook UX21E and UX31E drew comparisons to the Macbook Air and it was regarded as an "excellent rival" by CNET reviewer Andrew Hoyle. Other aspects of the laptops that reviewers liked were the Bang and Olufsen speakers, fast boot times due to Asus' BIOS design and the speed of general tasks within the operating system resulting from the SSD and Sandy Bridge processors. However, the screens drew criticism for their poor contrast ratio, colour accuracy and less than perfect viewing angle, although they were praised for their brightness and the sharpness of the UX31's screen. Reviewers also noted the shallow key-press of the metal keyboard and lack of backlighting, a feature that Asus did not have time to implement before shipping. The new screens on the ZenBook Prime were highly praised by reviewers when considering brightness, contrast ratio, viewing angle and colour accuracy, the improvements over previous models being put down to the switch from TN to IPS displays. The keyboard also garnered praise for the increased backlighting and improved key travel while the Intel Wi-Fi controller was found to perform better than the Qualcomm used in the first generation of Zenbooks. The Zenbook Primes still received some criticism: the latest version of the touchpad was acknowledged as an improvement over the original Zenbooks, but still irritating, and the sound quality was found to be worse than that with the first generation. Despite these issues, the overall reaction was positive: the UX31A was called "today's best ultrabook" and "the best ultrabook out there" at the time of release. The ZenBook UX32VD was well received for similar reasons to the Zenbook Prime. The screen, chassis and keyboard again garnered praise although the inclusion of a discrete GPU was noted as a major selling point. The hybrid drive attracted criticism for its slow performance and the same touchpad issues that the Zenbook Prime had were still present. SLR Lounge criticised the slow hybrid drive and 4 GB of RAM, but suggested replacing them as the option is available, noting that it was an option not often offered on ultrabooks. As a cheaper option the ZenBook UX32A was praised by Chris Martin of PC Advisor for being "a more affordable luxury", retaining the "premium feel" of the Zenbook range but at a lower price point. The aluminium chassis, which is identical to the UX32VD to keep costs down, was widely acclaimed for its strength and build quality. By contrast, the Sandy Bridge chip, a previous-generation part at the time of sale, was outlined as a detraction as was the lower battery life compared to the UX31E. Although the screen used was a TN panel and of a lower resolution than the UX32VD or UX31A, it was considered an acceptable compromise for the price. The screen has a matte finish and relatively high brightness which Notebook Check's reviewer, Christian Hepp, found "quite suitable for outdoor use", noting that it had a good contrast ratio but a narrow range of colours. The ZenBook UX42VS and UX52VS drew criticism for its high price and lack of touch screen, but the screen quality, keyboard and system speed were praised. The battery life was considered acceptable taking into account the form-factor and the discrete GPU, despite it being significantly shorter than the UX31A. AnandTech reviewer Jason Inofuentes found the touch screen to be so superior to the touchpad that he stopped using the touchpad altogether in his trial of a Zenbook Touch at the Asus launch event. Chris Griffith of The Australian found that the screen of the UX31A responded well and that the Windows 8 gestures worked predictably, his only criticism being the high price. The ZenBook UX430 is commonly reported to suffer from significant coil whine issues. References External links Asus products Subnotebooks Consumer electronics brands Products introduced in 2011 Ultrabooks

laptop Form Factor and Weight

Toshiba Thrive The Toshiba Thrive (AT100 in the UK and Singapore) was a 10.1" tablet computer running Android 3.2.1. PC World praised its full-sized and versatile SD card slot, HDMI port, and USB ports with host functionality and the ability to handle large external drives (up to 2 TB) as well as standard peripherals like USB Keyboards, printers and cameras. The review concluded that there were minor disadvantages including a bulky form and poor sound quality. CNET's review said "Its grooved back, full HDMI and USB support, full SD card slot, and replaceable battery justify its very bulky design." Features The Toshiba Thrive has a capacitive touch screen, 10.1 inches diagonally measured, with 1280x800 resolution. It comes with one gigabyte of RAM, and 8, 16 or 32 gigabytes of flash NAND memory. Its CPU is the Nvidia Tegra 2 dual-core mobile processor, capable of common tablet tasks like Android games and other apps, e-books, music, and 720p video. There is a 5-megapixel camera on the back, a 2-megapixel camera on the front, and stereo speakers on the bottom. Users can easily remove the Thrive's back cover and replace the battery (which is not the case with many tablets). Though thicker relative to other tablets, the Thrive has rare full-sized USB and HDMI ports, and an SD card slot. There is a mini USB port for communications with a PC, and a port on the bottom edge for Toshiba's proprietary dock. The USB port is popular for external storage (such as flash drives and self-powered hard drives), mice, and keyboards. The Thrive was first available online in the US on July 10, 2011. In early 2012, Toshiba quietly (without any press releases) introduced Thrive tablets (16 or 32 gigabytes of storage) with support for AT&T 4G HSPA+ mobile broadband. This capability added $80 to the standard prices. A Thrive with a 7-inch screen was demonstrated in September 2011 and released in December 2011. It weighs 13.3 ounces and has a smaller form factor, 7.44"x5.04"x0.48". However, the battery is not removable, and unlike the bigger Thrive's connections, it has micro HDMI and mini USB ports, and micro SD slot. It features the same front facing 2-megapixel camera. Upgrades There were official announcements about the availability of an upgrade to Android 4.0 (Ice Cream Sandwich) in early 2012, and in June 2012, it became available for certain Thrive models in the US, Canada and Australia. There have been numerous complaints about the stability of the stock release at the Thrive Forum, however. For other countries, the latest official version of Android available from Toshiba for this device is still 3.2.1. The Thrive is rarely found new from U.S. retail outlets, although refurbished and used units are popular. Toshiba's Excite series of tablets was the successor to the Thrive series, launched on March 6, 2012, with 7.7-inch, 10.1-inch and 13-inch versions. Upgrades to Android 4.0.4 were available in August 2012. The Excite has also been discontinued by Toshiba, with refurbished and used units available from a variety of sources. References External links ToshibaTablet.com www.thetoshibatablet.com/pdf/Toshiba%20PDF_V2.pdf reviews.cnet.com/tablets/toshiba-tablet Toshiba Thrive Tablet Toshiba Android (operating system) devices Tablet computers introduced in 2011 Tablet computers Discontinued products

laptop Form Factor and Weight

IEC 62700 IEC Technical Specification 62700: DC Power supply for notebook computer is an IEC specification of a common standard for external laptop computer AC adapters. Laptops and AC adapters following this standard will have interchangeable power supplies, which will enable easy reuse of used power supplies (thereby reducing electronic waste) and make buying a new compatible power supply for a laptop simpler. The specification was published on 6 February 2014. Alternatives Despite being an industry open organization with open participation, the standard has been criticized by some for not being openly available for review. Some alternatives include: IEEE has a proposed standard Universal Power Adapter for Mobile Devices for laptops and other devices. The USB Promoters Group's USB Power Delivery ("PD") specification supports up to 100 W, and is intended to be able to power laptops. EmPower (aircraft power adapter) is intended for passenger aircraft. See also Common external power supply - EN 62684 / IEC 62684, a widely adopted 2010 European specification standardizing smartphone power supplies on the USB Battery charging specification and USB connectors. References External links IEC/TS 62700 ed1.0 - DC power supply for notebook computers at the IEC Webstore IEC working groups for IEC 62700: Project Maintenance Power supplies 62700 Electronics and the environment

laptop Form Factor and Weight

MacBook Pro The MacBook Pro is a line of Macintosh notebook computers introduced in January 2006 by Apple Inc. It is the higher-end model of the MacBook family, sitting above the consumer-focused MacBook Air, and is currently sold with 13-inch, 14-inch, and 16-inch screens. All models from the current lineup use variants of the Apple-designed M1 system on a chip. The first-generation MacBook Pro used the design of the PowerBook G4, but replaced the PowerPC G4 chips with Intel Core processors, added a webcam, and introduced the MagSafe power connector. The 15-inch model was introduced in January 2006; the 17-inch model in April. Later revisions added Intel Core 2 Duo processors and LED-backlit displays. The second-generation model debuted in October 2008 in 13- and 15-inch variants, with a 17-inch variant added in January 2009. Called the "unibody" model because its case was machined from a single piece of aluminum, it had a thinner flush display, a redesigned trackpad whose entire surface consisted of a single clickable button, and a redesigned keyboard. Updates brought Intel Core i5 and i7 processors and introduced Intel's Thunderbolt. The third-generation MacBook Pro was released in 2012: the 15-inch in June 2012, a 13-inch model in October. It is thinner than its predecessor, made solid-state storage (SSD) standard, added HDMI, and included a high-resolution Retina display. It eliminated Ethernet and FireWire ports and the optical drive. The fourth-generation MacBook Pro, released in October 2016, adopted USB-C for all data ports and power and included a shallower "butterfly"-mechanism keyboard. On all but the base model, the function keys were replaced with a touchscreen strip called the Touch Bar with a Touch ID sensor integrated into the power button. A November 2019 revision to the fourth-generation MacBook Pro introduced the Magic Keyboard, which uses a scissor-switch mechanism. The initial 16-inch model with a screen set in narrower bezels was followed by a 13-inch model in May 2020. Another revision to the fourth generation was released in November 2020; it was the first MacBook Pro to feature an Apple-designed system on a chip, the Apple M1. The fifth-generation MacBook Pro was released in October 2021 in 14- and 16-inch sizes. Powered by either M1 Pro or M1 Max chips, they are the first to be available only with an Apple silicon system on a chip. In addition to being Apple Silicon-only, this generation re-introduced elements from the previous models which were removed at some point, such as MagSafe and function-keys. Intel-based First generation (Aluminum) The first-generation MacBook Pro used the design of the PowerBook G4, but replaced the PowerPC G4 chips with Intel Core processors, added a built-in iSight webcam, and introduced the MagSafe power connector. The optical drive was shrunk to fit into the slimmer MacBook Pro; it runs slower than the optical drive in the PowerBook G4 and cannot write to dual-layer DVDs. The 15-inch model was introduced in January 2006; the 17-inch model in April. Later revisions added Intel Core 2 Duo processors, and LED-backlit displays, the 15-inch in 2007 and 17-inch in 2008. The 2007 revision received new Nvidia Geforce 8600M GT video cards. and the 2008 revision upgraded the processors to "Penryn" cores while adding multi-touch capabilities to the trackpad. Both the original 15- and 17-inch model MacBook Pro computers come with ExpressCard/34 slots, which replace the PC Card slots found in the PowerBook G4. Initial first-generation 15-inch models retains the two USB 2.0 ports and a FireWire 400 port but drops the FireWire 800, until it was readded in a later revision, the 17-inch models have an additional USB 2.0 port, as well as the FireWire 800 port missing from the initial 15-inch models. All models now included 802.11a/b/g. Later models include support for the draft 2.0 specification of 802.11n and Bluetooth 2.1. The original case design was discontinued on October 14, 2008, for the 15-inch, and January 6, 2009, for the 17-inch. Models of the MacBook Pro built from 2007 to early 2008 (15") / late 2008 (17") using the Nvidia 8600M GT chip reportedly exhibited failures in which the GPU die would detach from the chip carrier, or the chip would detach from the logic board. Apple initially ignored reports, before admitting to the fault and replacing logic boards free of charge for up to 4 years after the purchase date. NVIDIA also confirmed the issue, and previously manufactured replacement GPUs, which some users have replaced themselves. Second generation (Unibody) On October 14, 2008, in a press event at company headquarters, Apple officials announced a new 15-inch MacBook Pro featuring a "precision aluminum unibody enclosure" and tapered sides similar to those of the MacBook Air. Designers shifted the MacBook Pro's ports to the left side of the case, and moved the optical disc drive slot from the front to the right side, similar to the MacBook. The new MacBook Pro computers had two video cards that the user could switch between: the Nvidia GeForce 9600M GT with either 256 or 512 MB of dedicated memory and a GeForce 9400M with 256 MB of shared system memory. The FireWire 400 port was removed. The DVI port was replaced with a Mini DisplayPort receptacle. The original unibody MacBook Pro came with a user-removable battery; Apple claimed five hours of use, with one reviewer reporting results closer to four hours on a continuous video battery stress test. Apple said that the battery would hold 80% of its charge after 300 recharges. The unibody-construction MacBook Pro largely follows the styling of the original aluminum iMac and the MacBook Air and is slightly thinner than its predecessor, albeit wider and deeper due to the widescreen display. The screen is high-gloss, covered by an edge-to-edge reflective glass finish, while an anti-glare matte option is available in the 15- and 17-inch models in which the glass panel is removed. The entire trackpad is usable and acts as a clickable button. The trackpad is also larger than that of the first generation, giving more room for scrolling and multi-touch gestures. When the line was updated in April 2010, inertial scrolling was added, making the scrolling experience much like that of the iPhone and iPad. The keys, which are still backlit, are now identical to those of Apple's now-standard sunken keyboard with separated black keys. The physical screen release latch from the previous generation is replaced with a magnetic one. During the MacWorld Expo keynote on January 6, 2009, Phil Schiller announced a 17-inch MacBook Pro with unibody construction. This version diverged from its 15-inch sibling with an anti-glare "matte" screen option (with the glossy finish standard) and a non user-removable lithium polymer battery. Instead of traditional round cells inside the casing, the lithium-ion polymer batteries are shaped and fitted into each notebook to maximally utilize space. Adaptive charging, which uses a chip to optimize the charge flow to reduce wear and tear, extends the battery's overall life. Battery life for the 17-inch version is quoted at eight hours, with 80 percent of this charge remaining after 1,000 charge-discharge cycles. At Apple's Worldwide Developers Conference (WWDC) on June 8, 2009, it was announced that the 13-inch unibody MacBook would be upgraded and re-branded as a MacBook Pro, leaving only the white polycarbonate MacBook in the MacBook line. It was also announced that the entire MacBook Pro line would use the non-user-removable battery first introduced in the 17-inch MacBook Pro. The updated MacBook Pro 13- and the 15-inch would each have up to a claimed 7 hours of battery life, while the 17-inch would keep its 8-hour capacity. Some sources even reported up to eight hours of battery life for the 13- and 15-inch MacBook Pro computers during casual use, while others reported around six hours. Like the 17-inch MacBook Pro, Apple claims that they will last around 1,000 charging cycles while still containing 80% of their capacity. Graphics card options stayed the same from the previous release, although the 13-inch and the base model 15-inch, came with only the GeForce 9400M GPU. The screens were also improved, gaining a claimed 60 percent greater color gamut. All of these mid-2009 models also included a FireWire 800 port and all except the 17-inch models would receive an SD card slot. The 17-inch model would retain its ExpressCard/34 slot. For the 13-inch MacBook Pro, the Kensington lock slot was moved to the right side of the chassis. In August 2009, Apple extended the "matte" anti-glare display option to the 15-inch MacBook Pro. On April 13, 2010, Intel Core i5 and Core i7 CPUs were introduced in the 15- and 17-inch models, while the 13-inch retained the Core 2 Duo with a speed increase. The power brick was redesigned and a high-resolution display (of ) was announced as an option for the 15-inch models. The 13-inch gained an integrated Nvidia GeForce 320M graphics processing unit (GPU) with 256 MB of shared memory, while the 15- and 17-inch models were upgraded to the GeForce GT 330M, with either 256 or 512 MB of dedicated memory. The 15- and 17-inch models also have an integrated Intel GPU that is built into the Core i5 and i7 processors. The 15-inch model also gained . Save for a third USB 2.0 slot, all the ports on the 17-inch MacBook Pro are the same in type and number as on the 15-inch version. All models come with 4 GB of system memory that is upgradeable to 8 GB. Battery life was also extended further in this update, to an estimated 10 hours for the 13-inch and 8–9 hours on the 15- and 17-inch MacBook Pro computers. This was achieved through both greater power efficiency and adding more battery capacity. One reviewer reported about 6 hours of battery life through a continuous video battery stress test in the 15-inch and another, who called the battery life "unbeatable", reported nearer to 8 in the 13-inch through their "highly demanding battery drain test". Thunderbolt technology, Sandy Bridge dual-core Intel Core i5 and i7 (on the 13-inch model) or quad-core i7 (on the 15- and 17-inch models) processors, and a high definition FaceTime camera were added on February 24, 2011. Intel HD Graphics 3000 come integrated with the CPU, while the 15- and 17-inch models also utilize AMD Radeon HD 6490M and Radeon HD 6750M graphics cards. Later editions of these models, following the release of OS X Lion, replaced the Expose (F3) key with a Mission Control key, and the Dashboard (F4) key with a Launchpad key. The chassis bottoms are also engraved differently from the 2010 models. The Thunderbolt serial bus platform can achieve speeds of up to 10 Gbit/s, which is up to twice as fast as the USB 3.0 specification, 20 times faster than the USB 2.0 specification, and up to 12 times faster than FireWire 800. Apple says that Thunderbolt can be used to drive displays or to transfer large quantities of data in a short amount of time. On June 11, 2012, Apple showcased its upgraded Mac notebooks, OS X Mountain Lion, and iOS 6 at the Worldwide Developers Conference (WWDC) in San Francisco. The new MacBook Pro models were updated with Ivy Bridge processors and USB 3.0 ports, and the default RAM on premium models was increased to 8 GB. Following this announcement, the 17-inch model was discontinued. After a media event on October 22, 2013, Apple discontinued all second-generation MacBook Pro computers except for the entry-level 2.5 GHz 13-inch model. Apple discontinued the 13-inch second-generation MacBook Pro on October 27, 2016. Prior to its discontinuation it was Apple's only product to still include an optical drive and a FireWire port, and only notebook with a hard disk drive and Ethernet port. It is also the only MacBook Pro to support 9 versions of MacOS X/MacOS, from Mac OS X Lion 10.7 through MacOS Catalina 10.15. Early and late 2011 models with a GPU; 15" & 17"; reportedly suffer from manufacturing problems leading to overheating, graphical problems, and eventually complete GPU and logic board failure. A similar but nonidentical problem affected iMac GPUs which were later recalled by Apple. The problem was covered by many articles in Mac-focused magazines, starting late 2013 throughout 2014. In August 2014 the law firm Whitfield Bryson & Mason LLP had begun investigating the problem to determine if any legal claim exists. On October 28, 2014, the firm announced that it has filed a class-action lawsuit in a California federal court against Apple. The lawsuit will cover residents residing in both California and Florida who have purchased a 2011 MacBook Pro notebook with an AMD graphics card. The firm is also investigating similar cases across the United States. On February 20, 2015, Apple instituted the This "will repair affected MacBook Pro systems, free of charge". The program covered affected MacBook Pro models until December 31, 2016, or four years from original date of sale. Third generation (Retina) The third-generation MacBook Pro was released in 2012, marketed as the "MacBook Pro with Retina display" to differentiate it from the previous model: the 15-inch in June 2012, a 13-inch model in October. It made solid-state storage (SSD) standard, upgraded to USB 3.0, added an additional Thunderbolt port, added HDMI, and included a high-resolution Retina display. The 15-inch model is 25% thinner than its predecessor. The model name is no longer placed at the bottom of the screen bezel; instead, it is found on the underside of the chassis, similar to an iOS device and is the first Macintosh notebook to not have its model name visible during normal use. It eliminated Ethernet, FireWire 800 ports, but Thunderbolt adapters were available for purchase,, Kensington lock slot, the battery indicator button and light on the side of the chassis, and the optical drive, being the first professional notebook since the PowerBook 2400c, but brought a new MagSafe port, dubbed the "MagSafe 2". Apple also claims improved speakers and microphones and a new system for cooling the notebook with improved fans. The Retina models also have fewer user-accessible upgrade or replacement options than previous MacBooks. Unlike in previous generations, the memory is soldered onto the logic board and is therefore not upgradable. The solid state drive is not soldered and can be replaced by users, although it has a proprietary connector and form factor. The battery is glued into place; attempts to remove it may destroy the battery and/or trackpad. The entire case uses proprietary pentalobe screws and cannot be disassembled with standard tools. While the battery is glued in, recycling companies have stated that the design is only "mildly inconvenient" and does not hamper the recycling process. The initial revision includes Intel's third-generation Core i7 processors (Ivy Bridge microarchitecture). Apple updated the line, on October 22, 2013, with Intel's Haswell processors and Iris Graphics, and 802.11ac Wi-Fi. The chassis of the 13-inch version was slightly slimmed to to match the 15-inch model. The lower-end 15-inch model only included integrated graphics while the higher-end model continued to include a discrete Nvidia graphics card in addition to integrated graphics. Support for 4K video output via HDMI was added but limited the maximum number of external displays from three to two. On March 9, 2015, the 13-inch model was updated with Intel Broadwell processors, Iris 6100 graphics, faster flash storage (based on PCIe 2.0 × 4 technology), faster RAM (upgraded from 1600MHZ to 1866MHZ), increased battery life (extended to 10 hours), and a Force Touch trackpad. On May 19, 2015, 15-inch model added Force Touch and changed the GPU to AMD Radeon R9 M370X, SSD based on PCIe 3.0 × 4 technology, the battery life was extended to 9 hours, and the rest of the configuration remained unchanged. The higher-end 15-inch model also added support for dual-cable output to displays. The 15-inch models were released with the same Intel Haswell processors and Iris Pro graphics as the 2014 models due to a delay in shipment of newer Broadwell quad-core processors. Apple continued to sell the 2015 15-inch model until July 2018. In June 2019, Apple announced a worldwide recall for certain 2015 15" MacBook Pro computers after receiving at least 26 reports of batteries becoming hot enough to produce smoke and inflict minor burns or property damage. The problem affected some 432,000 computers, mostly sold between September 2015 and February 2017. The company asked customers to stop using their computers until Apple could replace the batteries. In September 2019, India's Directorate General of Civil Aviation said MacBook Pro computers could dangerously overheat, leading the national carrier Air India to ban the model on its flights. Fourth generation (Touch Bar) Apple unveiled fourth-generation 13- and 15-inch MacBook Pro models during a press event at their headquarters on October 27, 2016. All models, except for the baseline 13-inch model, featured the Touch Bar, a new multi-touch-enabled OLED strip built into the top of the keyboard in place of the function keys. The Touch Bar is abutted on its right by a sapphire-glass button that doubles as a Touch ID sensor and a power button. The models also introduced a "second-generation" butterfly-mechanism keyboard whose keys have more travel than the first iteration in the Retina MacBook. The 13-inch model has a trackpad that is 46% larger than its predecessor while the 15-inch model has a trackpad twice as large as the previous generation. All ports have been replaced with either two or four combination Thunderbolt 3 ports that support USB-C 3.1 Gen 2 and dual DisplayPort 1.2 signals, any of which can be used for charging. The MacBook Pro is incompatible with some older Thunderbolt 3-certified peripherals, including Intel's own reference design for Thunderbolt 3 devices. Furthermore, macOS on MacBook Pro blacklists (prevents from working) certain classes of Thunderbolt 3-compatible devices. Support for Thunderbolt 3 external graphics processing units (eGPU) was added in macOS High Sierra 10.13.4. Devices using HDMI, previous-generation Thunderbolt, and USB need an adapter to connect to the MacBook Pro. The models come with a 3.5 mm headphone jack; the TOSLINK functionality of older-generation MacBook Pro computers has been removed. Other updates to the MacBook Pro include dual- and quad-core Intel "Skylake" Core i5 and i7 processors, improved graphics, and displays that offer a 25% wider color gamut, 67% more brightness, and 67% more contrast. All versions can output to a 5K display; the 15-inch models can drive two such displays. The 15-inch models include a discrete Radeon Pro 450, 455 or 460 graphics card in addition to the integrated Intel graphics. The base 13-inch model has function keys instead of the Touch Bar, and just two USB-C ports. The flash storage in the Touch Bar models is soldered to the logic board and is not upgradeable, while in the 13-inch model without Touch Bar, it is removable, but difficult to replace, as it is a proprietary format of SSD storage. On June 5, 2017, Apple updated the line with Intel Kaby Lake processors and newer graphics cards. A 128 GB storage option was added for the base 13-inch model, down from the base 256 GB storage. New symbols were introduced to the control and option keys. On July 12, 2018, Apple updated the Touch Bar models with Intel Coffee Lake quad-core processors in 13-inch models and six-core processors in 15-inch models, updated graphics cards, third-generation butterfly keyboards that introduced new symbols for the control and option keys, Bluetooth 5, T2 SoC Chip, True Tone display technology, and larger-capacity batteries. The 15-inch model can also be configured with up to 4 TB of storage, 32 GB of DDR4 memory and a Core i9 processor. In late November the higher-end 15-inch model could be configured with Radeon Pro Vega graphics. On May 21, 2019, Apple announced updated Touch Bar models with newer processors, with an eight-core Core i9 standard for the higher-end 15-inch model, and an updated keyboard manufactured with "new materials" across the line. On July 9, 2019, Apple updated the 13-inch model with two Thunderbolt ports with newer quad-core eighth-generation processors and Intel Iris Plus graphics, True Tone display technology, and replaced the function keys with the Touch Bar. macOS Catalina added support for Dolby Atmos, Dolby Vision, and HDR10 on 2018 and newer models. macOS Catalina 10.15.2 added support for 6016x3384 output on 15-inch 2018 and newer models to run the Pro Display XDR at full resolution. The 2019 MacBook Pro was the final model that could run macOS Mojave 10.14, the final MacOS version that can run 32-bit applications such as Microsoft Office for Mac 2011. Design and usability The fourth-generation MacBook Pro follows the design of the previous two generations, with an all-metal unibody enclosure and separated black keys. A few of the apparent design changes include a thinner chassis and screen bezel, a larger trackpad, the OLED Touch Bar, and the shallower butterfly-mechanism keyboard with less key separation than the previous models. The speaker grilles have been relocated to the sides of the keyboard on the 13-inch variant. Tear downs show that the speaker grilles on the 13-inch model with Touch Bar are "largely cosmetic", and that sound output mostly comes through the side vents. The fourth generation MacBook Pro comes in two finishes, the traditional silver color and a darker "space gray" color. The MacBook Pro model name returns to the bottom of the screen bezel in Apple's San Francisco font after being absent from the second generation with Retina display. As with the Retina MacBook, the new models replace the backlit white Apple logo on the rear of the screen, a feature dating back to the 1999 PowerBook G3, with a glossy metal version. MagSafe, a magnetic charging connector, has been replaced with USB-C charging. Unlike MagSafe, which provided an indicator light within the user's field of view to indicate the device's charging status, the USB-C charger has no visual indicator. Instead, the MacBook Pro emits a chime when connected to power. The Macintosh startup chime that has been used since the first Macintosh in 1984 is now disabled by default. The notebook now boots automatically when the lid is opened. Battery life The battery life of the new models also got a mixed reception, with outlets reporting inconsistent battery life and inaccurate estimates of time remaining on battery by the operating system. After the latter reports, Apple used a macOS update to hide the display of estimated battery time. Consumer Reports did not initially recommend the 2016 MacBook Pro models, citing inconsistent and unpredictable battery life in its lab testing (which involves the consecutive loading of multiple websites). However, Apple and Consumer Reports found that the results had been affected by a bug caused by disabling caching in Safari's developer tools. Consumer Reports performed the tests again with a patched macOS, and retracted its original assessment. Repairability iFixit scored the models 1 out of 10 for repairability, noting that memory, the processor, and flash storage are soldered to the logic board, while the battery is glued to the case. The entire assembly uses proprietary pentalobe screws and cannot be disassembled with standard tools. Keyboard reliability A report by AppleInsider has claimed that the updated "Butterfly" keyboard fails twice as often as previous models, often due to particles stuck beneath the keys. Repairs for stuck keys have been estimated to cost more than $700. In May 2018, two class action lawsuits were filed against Apple regarding the keyboard problem; one alleged a "constant threat of nonresponsive keys and accompanying keyboard failure" and accusing Apple of not alerting consumers to the problem. In June 2018, Apple announced a Service Program to "service eligible MacBook and MacBook Pro keyboards, free of charge". The 2018 models added a membrane underneath keys to prevent malfunction from dust. As of early 2019, there were reports of problems with the same type of keyboards in the 2018 MacBook Air. In May 2019, Apple modified the keyboard for the fourth time and promised that any MacBook keyboard with butterfly switches would be repaired or replaced free of charge for a period of four years after the date of sale. Thermal throttling PC Magazine said "the Core i9 processor Apple chose to use inside the MacBook Pro (i9-8950K) has a base clock frequency of 2.9GHz, which is capable of bursting up to 4.8GHz when necessary. However, testing carried out by YouTuber Dave Lee showed that the Core i9 couldn't even maintain 2.9GHz, let alone 4.8GHz. And it ended up running at 2.2GHz due to the heat generated inside the chassis forcing it to throttle. Lee found the 2018 i9 MacBook Pro was slower than the 2017 MacBook Pro and stated, "This isn't a problem with Intel's Core i9, it's Apple's thermal solution." When Lee put the i9 MacBook Pro inside a freezer, the render times were over 30% faster. On July 24, 2018, Apple released a software fix for the new 2018 MacBook Pro computers which addressed the thermal throttling problem. Apple said "there is a missing digital key in the firmware that impacts the thermal management system and could drive clock speeds down under heavy thermal loads on the new MacBook Pro". Other problems A "limited number" of 13-inch MacBook Pro units without Touch Bar, manufactured between October 2016 and October 2017, saw the built-in battery swell. Apple created a free replacement program for eligible units. A "limited number" of 128 and 256 GB solid-state drives used in 13-inch MacBook Pro (non-Touch Bar) units can lose data and fail. 13-inch MacBook Pro units with affected drives were sold between June 2017 and June 2018. This resulted in Apple launching a repair program for those affected – the repair involves the update of firmware. Some users are reporting kernel panics on 2018 models, because of the T2 chip. Apple is already aware of the problem and performing an investigation. There are also user reports about the speaker crackling problems on the 2018 models. Users have reported malfunctioning display cables, causing uneven lighting at the bottom of the screen and ultimately display failure. Customers of Apple have named this issue "Flexgate". The problem has been tracked to a cable, stressed from opening and closing the notebook. The entire display needs to be replaced in affected units. In May 2019 Apple initiated a program to replace the display on affected 13-inch models made in 2016 for free, and the cable on the 2018 models and onwards was made 2 mm longer than on prior models, thus reducing the likelihood of display failure . Apple has been criticized for not extending the replacement program to the 15-inch models which are also affected by this issue. Reception The fourth-generation MacBook Pro received mixed reviews. The display, build quality, and audio quality were praised but many complained about the butterfly keyboard; the little-used Touch Bar; and the absence of USB-A ports, HDMI port, and SD card slot. Ars Technica noted that the second-generation keyboard with firm keys was a "drastic departure" from previous Retina MacBook keyboards. It further noted that resting palms may brush the trackpad occasionally, causing inadvertent cursor jumps onscreen as the notebook interprets this as input, without one's hands or wrists actually resting on it. Bandwidth increased; the flash storage was about 40 percent faster. Engadget praised the thinner, lighter design; improved display and audio; and increased speed of the graphics and flash storage, but criticized the lack of ports and the price. Wired praised the display, calling it "the best laptop display I've ever seen", as well as praising the Touch Bar, though it criticized the need of adapters for many common connectors. Likewise, The Verge concluded that "using [the new MacBook] is alienating to anyone living in the present. I agree with Apple's vision of the future. I'm just not buying it today." Engadget voiced their concerns that "by doing things like removing full-sized USB ports, the memory card reader and even the Function row, Apple seems to have forgotten how many of us actually work". Heavy keyboard users criticized the Touch Bar, noting that command-line tools like Vim rely on keyboard usage, and the Touch Bar does not provide the tactile feedback necessary for "blind" usage of Function keys. Miriam Nielsen from The Verge said: "When I tried to intentionally use the Touch Bar, I felt like a kid learning how to type again. I had to keep looking down at the bar instead of looking at the images I was actually trying to edit." She also said that after learning the Touch Bar one cannot work as efficiently on any other computer. Developers have their share of headaches because they cannot rely on the Touch Bar being present on every machine that runs their software. Even if Apple makes the Touch Bar an integral part of macOS, it will take "many years" for it to become ubiquitous, in the meantime, anything in the Bar needs to be available through another part of the interface. Also criticized were non-compatibility between Thunderbolt 2 and 3 devices. Some found unpleasant the fan whine on the 15" model, where the two integrated fans run all the time by default, thanks to the coprocessor powering the Touch Bar and higher TDP of the stronger CPU models. In 2016 and 2017, the Touch Bar caused concern among American state bars that the predictive text could be used to cheat on bar exams. The responses varied state by state: New York State Bar Association banned the use of the MacBook Pro on bar exams; while North Carolina Bar Association allowed students to take the state bar exam with the computer once a proctor verified that the predictive text feature had been disabled. Magic Keyboard revision Apple unveiled the fifth revision of the fourth generation MacBook Pro in 2020, the 16-inch MacBook Pro on November 13, 2019, replacing the 15-inch model. Similar in size to the 15-inch model, it has a larger 16-inch 3072x1920 Retina display set in a narrower bezel, the largest MacBook screen since the 17-inch unibody MacBook Pro that was discontinued in 2012. It has a physical Escape key, a Touch Bar, and a now-separate sapphire-glass-covered Touch ID sensor at the right end of the Touch Bar that doubles as a power button. It uses a scissor mechanism keyboard almost identical to Apple's wireless Magic Keyboard, providing more travel than the previous revision's "Butterfly" keyboard. Like its predecessor, the 16-inch MacBook Pro has four combined Thunderbolt 3 ports that support USB-C 3.1 Gen 2 and dual DisplayPort 1.4 signals, providing 6016×3384 output to run the Pro Display XDR at full resolution. Any port can be used for charging, it includes a 96 W USB-C power adapter. At launch only the included adapter and the Pro Display XDR provide full host power. Peripherals that delivered 87 W for the 15-inch model, such as LG Ultrafine displays, are recommended to be used with a separate power supply. It also has a 3.5 mm headphone jack. It uses the same Coffee Lake CPUs as the 2019 15-inch model. Purchasers can choose between AMD Radeon Pro 5300M or 5500M GPUs with up to 8 GB of GDDR6 memory (or from June 2020 onwards, a 5600M GPU with 8 GB of HBM2 memory), up to 64 GB of 2667 MHz DDR4 memory, and up to 8 TB of SSD storage. It includes better speakers, a better three-microphone array, and a 100 Wh battery, the largest that can be easily carried onto a commercial airliner under U.S. Transportation Security Administration rules. On May 4, 2020, Apple announced an updated 13-inch model with the Magic Keyboard. The four Thunderbolt port version comes with Ice Lake processors, updated graphics, up to 32 GB of memory and 4 TB of storage, and supports 6K output to run the Pro Display XDR. The two Thunderbolt port version has the same Coffee Lake processors, graphics, and maximum storage and memory as the 2019 two Thunderbolt port models. The 2020 13-inch models also gain 0.02 inches (0.6 mm) in thickness over the 2019 models. Reception Reception to the 16-inch MacBook Pro was generally positive. LaptopMag called the keyboard "much-improved". The Verge praised the new keyboard, microphones, and speakers, but criticized the lack of peripherals such as an SD card slot. 9to5Mac criticized the use of a 720p webcam and older 802.11ac Wi-Fi standard, noting that Apple's iPhone 11 family included a 4K front-facing camera and faster Wi-Fi 6. MacWorld also noted the lack of Face ID. Another review noted that the 2020 two Thunderbolt port 13-inch model is unable to run Apple's Pro Display XDR at full resolution, while the lower-priced 2020 MacBook Air can. There are numerous reports of cracked screens caused by closing the unit with a third-party physical webcam cover due to reduced clearance compared to previous models. Apple silicon Fourth generation (Touch Bar, Apple silicon revision) On November 10, 2020, Apple introduced a new generation of two-port 13-inch MacBook Pro with a brand new Apple-designed Apple M1 processor, launched alongside an updated MacBook Air and Mac Mini as the first Macs with Apple's new line of custom ARM-based Apple silicon processors. The MacBook Pro with Apple silicon retains the same form factor/ design while adding support for Wi-Fi 6, USB4, and 6K output to run the Pro Display XDR. The number of supported external displays was reduced to one, as the previous generation Intel-based models supported two 4K displays. The FaceTime camera remains 720p but Apple advertises an improved image signal processor for higher quality video. Fifth generation (M1 Pro and M1 Max) Apple announced a new 14-inch MacBook Pro, replacing the high-end 13-inch Intel MacBook Pro, and a redesigned 16-inch MacBook Pro during an online event on October 18, 2021. They are equipped with the new Apple Silicon chips, M1 Pro and M1 Max, Apple's second ARM-based systems on a chip and their first professional-focused chips. This release addressed many criticisms of the previous generation by reintroducing hard function keys in place of the Touch Bar, an HDMI 2.0 port, a SDXC reader and MagSafe charging. Other additions include a Liquid Retina XDR display with thinner bezels and an iPhone-like notch, ProMotion supporting 120 Hz variable refresh rate, a 1080p webcam, Wi-Fi 6, 3 Thunderbolt 4 ports, and a six-speaker sound system supporting Dolby Atmos. The M1 Pro chip supports up to two external displays, both at 6K resolution, while the M1 Max chip supports up to four displays: three at 6K resolution, and one at 4K resolution. The 16-inch version is bundled with a 140 W GaN power supply that supports USB-C Power Delivery 3.1, though only MagSafe supports full-speed charging as the machine's USB-C ports are limited to 100 W. The M1 Pro and M1 Max MacBook Pro models feature a thicker and more-squared design than their immediate Intel-based predecessors. The keyboard features full-sized function keys, with the keyboard set in a "double anodized" black well. The MacBook Pro branding has been removed from the bottom of the display bezel and is engraved on the underside of the chassis instead. The models' appearance has been compared to the Titanium PowerBook G4 produced from 2001 to 2003. The choice between silver or space gray color introduced in the fourth generation continues in the fifth. See also Comparison of Macintosh models MacBook (12-inch) MacBook Air Notes References External links – official site Computer-related introductions in 2006 MacBook X86 Macintosh computers ARM Macintosh computers

laptop Form Factor and Weight

Homebuilt computer A custom-built or homebuilt computer is a computer assembled from available components, usually commercial off-the-shelf (COTS) components, rather than purchased as a complete system from a computer system supplier, also known as pre-built systems. Custom-built or homebuilt computer is usually considered cheaper to assemble as compared to buying a pre-built computer, since it excludes the labour associated with building a computer, and instead the labor is done by the end-user in assembling their own homebuilt computer. Homebuilt computers are almost always used at home, like home computers, but home computers were traditionally purchased already assembled by the manufacturer. However, there were kits that were both home computers and homebuilt computers, like the Newbear 77-68, which the owner was expected to assemble and use in his or her home. History Computers have been built at home for a long time, starting with the Victorian era pioneer Charles Babbage in the 1820s. A century later, Konrad Zuse built his own machine when electromechanical relay technology was widely available. In 1965, electronics engineer James Sutherland started building a computer out of surplus parts from his job at Westinghouse. The hobby really took off with the early development of microprocessors, and since then many enthusiasts have constructed their own computers. Early examples include the Altair 8800 from the United States and the later British Newbear 77-68 and Nascom designs from the late 70's and early 80's. Some were made from kits of components, or simply distributed as board designs like the Ferguson Big Board. The Altair 8800 pioneered the S-100 bus which somewhat simplified the process. Ultimately, the development of home computers, the IBM PC (and its derivatives and clones), and the industry of specialized component suppliers that grew up around this market in the mid 80's have made building computers much easier. Computer building is no longer limited to specialists. Computers based on Apple Macintosh and Amiga computer platforms often can not be built in general by users legally because of patents and licenses for their hardware, firmware, and software. Development as a hobby At one time building desktop PCs was a popular hobby. Not only could someone build a desktop that outperformed pre-built models selling in retail stores, but someone building their own computer may add whatever components they want, from multiple hard drives, case mods, high-performance graphics cards, liquid cooling, multi-head high-resolution monitor configurations, or using alternative operating systems without paying the "Microsoft tax". As pre-built computers improved in quality and performance, and manufacturers offered more options, it became less cost-effective for most users to build their own computers, and the hobby declined. The growing popularity of laptops and tablets led to a mobile first design methodology that is difficult for home builders to duplicate economically. Recently PC parts have become cheaper, and people are starting to build computers again. With the rise of virtual reality headsets (VR) such as the HTC Vive, the demand for high performance has risen. Competitive games with their own dedicated tournaments have brought about more builders due to more effective customization in performance. Standardization Practically all PCs and some laptops are built from readily interchangeable standard parts. Even in the more specialized laptop market, a considerable degree of standardization exists in the basic design, although it may not be easily accessible to end-users. Although motherboards are specialized to work only with either Intel or AMD processors, all other parts like Graphic Processors, RAM, Chassis/Computer cases have been standardized to fit any setup. The availability of standard PC components has led to the development of small scale custom PC assembly. So-called white box PC manufacturers and commercial "build to order" services range in size from small local supply operations to large international operations. Kits and barebones systems Computer kits include all of the hardware (and sometimes the operating system software, as well) needed to build a complete computer. Because the components are pre-selected by the vendor, the planning and design stages of the computer-building project are eliminated, and the builder's experience will consist solely of assembling the computer and installing the operating system. The kit supplier should also have tested the components to assure that they are compatible. A barebones computer is a variation on the kit concept. A barebones system typically consists of a computer case with a power supply, motherboard, processor, and processor cooler. A wide variety of other combinations are also possible: some barebones systems come with just the case and the motherboard, while other systems are virtually complete. In either case, the purchaser will need to obtain and install whatever parts are not included in the barebones kit (typically the hard drive, Random Access Memory, peripheral devices, and operating system). Like mass-produced computers, barebones systems and computer kits are often targeted to particular types of users, and even different age groups. Because many home computer builders are gamers, for example, and because gamers are often young people, barebones computers marketed as "gaming systems" often include features such as neon lights and brightly coloured cases, as well as features more directly related to performance such as a fast processor, a generous amount of RAM, and a powerful video card. Other kits and barebones systems may be specifically marketed to users of a free software operating system such as Linux or one of the BSD variants, with components guaranteed for compatibility and performance with that operating system. Scavenged and "cannibalized" systems Many amateur-built computers are built primarily from used or "spare" parts. It's sometimes necessary to build a computer that will run an obsolete operating system or proprietary software for which updates are no longer available, and which will not run properly on a current platform. Economic reasons may also require an individual to build a new computer from used parts, especially among youth or in developing countries where the cost of new equipment places it out of reach of average people. Advantages and disadvantages Building one's own computer affords tangible benefits compared to purchasing a mass-produced model, such as: To make a computer customized to fit the user's needs in regard to quality, price, and availability. To recycle an older computer, or to upgrade internal components such as the motherboard, CPU, video card, etc. To build a high end computer using only top-quality parts for gaming, multimedia, or other demanding tasks. To avoid trial software and other commission-driven additions that are made to mass-market computers prior to their being shipped. To ensure the use of industry-standard parts for operating system compatibility or to upgrade the original build at a later date with little hassle. To ensure that one has all the individual driver and OS discs - many manufactured computers only come with one or two discs, one containing the OS, and another containing the drivers required, plus all the shovelware that was initially installed. Enjoyment, personal satisfaction, and educational experience. Tend to use higher quality parts as OEM's tend to user cheaper and lower quality parts. In most cases, building a computer themselves is much cheaper when they compare the specifications. There are drawbacks to building one's own PC: A poorly designed system may have flaws that would be exposed during a manufacturer's testing. A case chosen on the basis of looks may have poor ventilation if the CPU is overclocked. Someone assembling a PC must educate themselves on how all the components work and how they interact, things like air flow, compatibility of each component with other components, space constraints inside the computer case, PCIe lanes and slots are some of the major points to educate themselves on before building a computer. Studying a guide on building and buying computer components is advised. The lack of technical support and warranty protection other than what may be provided by the individual component and software vendors. However, a person assembling a PC likely has the expertise to maintain the system, and would require little assistance from manufacturers. Finding certain components and knowing whether components are compatible or not without prior knowledge on PC parts. Custom-built computers and alternative operating systems Because almost all mass-manufactured PCs ship with some version of Microsoft Windows pre-installed, individuals who wish to use operating systems other than Windows (for example, Linux or BSD) often choose to build their own computers. Their reason for doing so is not always related to saving money on an operating system. Because Microsoft Windows is the de facto standard operating system for PCs, hardware device drivers of different qualities can readily be found that will enable virtually any component designed for the PC architecture to function on a Windows platform. However, the same isn't true for alternative operating systems like Linux and BSD, so these system users have to be careful to avoid hardware that is incompatible with their choice of operating system. Even among hardware devices that technically will "work" with these alternative operating systems, some will work better than others. Therefore, many users of non-Microsoft operating systems choose to build their own computers from components known to work particularly well with their preferred platforms. A less common but still relevant option for people who choose to go another route when building their own PC and choosing their operating system may choose to configure what is called a Hackintosh system. This means that the user of the computer builds the computer specifically with the Mac OS in mind. This can often be a very tedious process as Apple has strict standards of what hardware they choose works with their software or not. Following previously built systems that worked is very important for success in this area. This is not generally a recommended route, but this hasn't stopped curious enthusiasts from achieving success. Custom-built computers and high-performance systems Most mainstream manufactured computers use common or inexpensive parts such as onboard graphics and audio. While integrated accessories offer dramatic economic savings (and satisfy many users), these options generally do not perform as well as dedicated hardware under high demand situations such as current games, CAD and media production. Homebuilt computers are most common among gamers, engineers, or other people who demand more performance from a specific component than the average user. An example would be a gamer using a slightly behind-the-curve CPU and disk drive, spending the difference on a more capable dedicated graphics card. Additionally, those with more specific computer needs usually appreciate being able to upgrade certain components to fit their needs and the evolving needs of the software being used; in a typical manufactured PC the support components (such as power supply unit, motherboard, or even the chassis) are unfit for accepting high-performance add-in components. Constructing a system with future expansion in mind allows for such upgrades, which in turn are much cheaper than buying a brand new computer every time individual components become obsolete or insufficient to meet the needs of the user. High-end PCs most often fall in the realm of heavy processor and/or memory usage applications such as a multimedia PC, home theater PC, music production, engineering, and many more. Generally a high-end system is capable of meeting the demands of gaming and can be used as such. A major difference between a high-end PC and a gaming PC is likely to only be the choice in video card since they will share a majority of other components. While a general-purpose high-end computer may be put to use in a render farm or as a file server, and be provisioned with components targeted at this use (such as a fast GPU for rendering or high-performance storage for serving files), most gaming takes place in real time so with a gaming PC all the components matter in creating a flawless and seamless experience. A less-intensive type of build satisfies or exceeds the needs of most computer users. See also White box (computer hardware) Hackintosh Barebone computer Enthusiast computing References External links Personal computers DIY culture

laptop Form Factor and Weight

Osborne 1 The Osborne 1 is the first commercially successful portable computer, released on April 3, 1981 by Osborne Computer Corporation. It weighs , cost US$1,795, and runs the CP/M 2.2 operating system. It is powered from a wall socket, as it has no on-board battery, but it is still classed as a portable device since it can be hand-carried when the keyboard is closed. The computer shipped with a large bundle of software that was almost equivalent in value to the machine itself, a practice adopted by other CP/M computer vendors. Competitors quickly appeared, such as the Kaypro II. History The Osborne 1 was developed by Adam Osborne and designed by Lee Felsenstein, first announced in early 1981. Osborne, an author of computer books decided that he wanted to break the price of computers. The computer's design was based largely on the Xerox NoteTaker, a prototype developed at Xerox PARC in 1976 by Alan Kay. It was designed to be portable, with a rugged ABS plastic case and a handle. The Osborne 1 is about the size and weight of a sewing machine and was advertised as the only computer that would fit underneath an airline seat. It is now classified as a "luggable" computer when compared to those later "laptop" designs such as the Epson HX-20. The Osborne 1 was described as "a cross between a World War II field radio and a shrunken instrument panel of a DC-3", and Felstenstein admitted that carrying two of them to a trade show "nearly pulled my arms out of their sockets". The computer nonetheless amazed observers; InfoWorld reported that "By far the most frequently asked question at" the West Coast Computer Faire "was, 'What do you think of the new Osborne computer?'" BYTE Magazine wrote: "(1) it will cost $1795, and (2) it's portable!" The word processing, spreadsheet, and other bundled software alone was worth $1,500; as InfoWorld stated in an April 1981 front-page article on the new computer after listing the included software, "In case you think the price printed above was a mistake, we'll repeat it: $1795". West Coast Computer Faire attendees stated, InfoWorld said, that the Osborne 1 "represented an advancement of the price/performance ratio for microcomputers". Adam Osborne agreed but emphasized the price, stating that its performance was "merely adequate": "It is not the fastest microcomputer, it doesn't have huge amounts of disk storage space, and it is not especially expandable." Beyond the price, advertisements emphasized the computer's portability and bundled software. The company sold 11,000 units in the first eight months of sales, and sales at their peak reached 10,000 units per month. The Osborne 1's principal deficiencies are a tiny display screen, use of single-sided, single-density floppy disk drives which store 90 kB per disk, and considerable unit weight. Adam Osborne decided to use single-sided disk drives out of concern about double-sided drives suffering head damage from rough handling. A single-density disk controller was used to keep costs down. In September 1981, Osborne Computer Company had its first $1 million sales month. Sales were hurt by the company's premature announcement of superior successor machines such as the Osborne Executive, which replaced the Osborne 1's 52 character screen with an 80 character screen. This phenomenon was later called the Osborne effect. From 1982 to 1985, the company published The Portable Companion, a magazine for Osborne users. Early production The company initially had ten prototypes produced, as described in an email by Felstenstein: Competition The computer was widely imitated as several other computer companies began offering low-priced portable computers with bundled software. The Osborne's popularity was surpassed by the similar Kaypro II which has a larger, CRT that can display 80 characters on 24 lines, and double density floppies that can store twice as much data. Osborne Computer Corporation was unable to effectively respond to Kaypro until after 8-bit, CP/M-based computers were obsolete. In 1981, IBM released the IBM PC which is significantly more powerful and expandable. Following the release of the IBM-compatible Compaq Portable in 1983, the market for CP/M computers shrank and Osborne was unable to compete. Architecture The 64 KB main memory is made of four rows of eight type 4116 dynamic RAM chips, each with 16,384 bits. Memory is shared, with 60 KB available for software and 4 KB reserved for video memory. No parity is provided and no provision for memory expansion exists on the motherboard. The boot program loader and significant parts of the BIOS are stored in a 4 kilobyte EPROM, which is bank-switched. A second EPROM is used as a fixed character generator, providing 96 upper and lower case ASCII characters and 32 graphic symbols; the character generator is not accessible to the CPU. The eighth bit of an ASCII character is used to select underlined characters. Serial communications is through a memory-mapped Motorola MC6850 Asynchronous Communications Interface Adapter (ACIA); a jumper on the motherboard allows the MC6850 to be set for either 300 and 1200 baud or 600 and 2400 baud communications, but other bit rates are not available. The floppy disk drives are interfaced through a Fujitsu 8877 disk controller integrated circuit, a second-source of the Western Digital 1793. The parallel port is connected through a memory-mapped Motorola MC6821 Peripheral Interface Adapter (PIA) which allows the port to be fully bidirectional; the Osborne manuals claim that the port implemented the IEEE-488 interface bus but this is rarely used. The parallel port use a card-edge connector etched on the main board, exposed through a hole in the case; any IEEE-488 or printer cable has to be modified for the Osborne. The diskette drives installed in the Osborne 1 are Siemens FDD 100-5s (MPI drives were also used later), which were actually manufactured in California by GSI, a drive manufacturer that the German firm had purchased. They utilize a custom controller board that Osborne produced, which among other things has a single connector for the power and data lines. The FDD 100-5 was trouble-prone as Osborne's quality control was lacking, and many of the controller boards have soldering defects. In addition, the drive cable is not keyed and can be easily installed upside-down, which shorts out components in the computer. There are also problems with the drive head going past track 0 and getting stuck in place. The combo power/data cable also has a tendency of overheating. The video system use part of the main memory and TTL logic to provide video and sync to an internal 5-inch monochrome monitor. The same signals are provided on a card edge connector for an external monitor; both internal and external monitor display the same video format. The internal monitor is specified as 3.55" horizontal, and 2.63" vertical making the actual viewing size even smaller at 4.42". Osborne also provided a 12" GM-12 external monitor. The processor, memory, floppy controller, PIA, ACIA and EPROMs are interconnected with standard TTL devices. The Osborne 1 has bank switched memory. Unusually for a system based on the Z80, all I/O is memory mapped, and the Z80 I/O instructions are only used to select memory banks. Bank 1 is "normal" mode, where user programs ran; this includes a 4 kB area at the top of the address space which is video memory. Bank 2 is called "shadow". The first 4 kB of this address space is the ROM, and 4 kB is reserved for the on-board I/O ports: The disk controller, the keyboard, the parallel port PIA, the serial port ACIA, and a second PIA chip used for the video system. All memory above the first 16 KB is the same memory as Bank 1. This is the mode of the system on power up, because this is where the boot ROM was mapped. Bank 3 has only 4 kb by 1 bit of memory, used solely to hold the "dim" attribute of the video system. Operating system The computer runs on the CP/M 2.2 operating system. A complete listing of the ROM BIOS is in the Osborne technical manual. Software The Osborne 1 came with a bundle of application software with a retail value of more than US$1500, including the WordStar word processor, SuperCalc spreadsheet, and the CBASIC and MBASIC programming languages. The exact contents of the bundled software varied depending on the time of purchase; for example, dBASE II was not included with the first systems sold. Hardware Dual 5¼-inch, single-sided, single-density 40 track floppy disk drives ("dual-density" upgrade available) 4 MHz Z80 CPU 64 KB main memory Fold-down 69 key detachable keyboard doubling as the computer case's lid 5-inch, 52 character × 24 line monochrome CRT display, mapped as a window on 128 × 32 character display memory Parallel printer port configurable as an IEEE-488 port RS-232 compatible 1200 or 300 baud Serial port for use with external modems or serial printers The Osborne 1 is powered by a wall plug with a switched-mode power supply, and has no internal battery. An aftermarket battery pack offering 1-hour run-time is available, and connected to the system through a front panel socket. OCC also sold the POWR-PAC inverter that allows running an Osborne from a 12 volt car cigarette lighter. Early models (tan case) are wired for 120 V or 240 V only. Later models (blue case, AKA Osborne 1A/1B, shipping after May 1982) can be switched by the user to run on either 120 V or 230 V, 50 or 60 Hz. There is no internal fan; a hatch at the top of the Osborne 1A/1B (blue case) can be slid open for ventilation. Peripherals Osborne and other companies produced many Osborne 1 accessories: External Monochrome display. This uses separate monochrome synch and video connections driven by the motherboard video circuitry. Parallel Dot matrix printer. Manufactured by Star. "Osborne DATACOM" 300 baud modem. Fits into the left diskette storage pocket and powered from the motherboard. Sold by OCC as the COMM-PAC which also included the AMCALL software. Aftermarket vendors offered several other upgrades to the basic model, including third-party double density disk drives, external hard disks, and a battery-backed RAM disk that fits in a disk storage compartment. Osborne Computer Corporation offered a "Screen-Pac" column upgrade that could be switched between original 52 column, 80 column and 104 column modes. Osborne 1 systems with the Screen-Pac upgrade have an RCA jack installed on the front panel to allow users to connect an external composite video monitor. This modification was developed in Australia by Geoff Cohen and Stuart Ritchie, and taken to the US by Stuart who turned up unannounced and sat outside Adam Osborne's office for two days. Osborne bought the mod and both of them worked with the company to implement the mod. As a nod toward where it came from, it was called the "Koala Project". Geoff developed other upgrades for Osborne's and was regarded as the Australian expert on the computers. Games Since, like most CP/M systems, the display of the Osborne does not support bit-mapped graphics, games are typically character based games, like Hamurabi or text adventures (the 1982 game Deadline, for example, packaged in a dossier type folder and came on two 5" diskettes.). Compiled and MBASIC interpreted versions of Colossal Cave Adventure are available for the Osborne. Some type in games use the Osborne's character-mode graphics. Reception InfoWorld reported that Osborne's booth at the April 1981 West Coast Computer Faire "was packed for the entire show". Although attendees' opinions were divided—some praised the computer, while others said that the screen was too small—many agreed "that the Osborne 1 represented an advancement of the price/performance ratio for microcomputers", the magazine said. Jerry Pournelle wrote that the small size of the Osborne's screen surprised him by not being a problem, and stated that after using it at Caltech when Voyager 1 arrived at Saturn, "a dozen science writers were ready to go buy an Osborne 1". He added, "I was able to type ... without disrupting the meeting at all. The Osborne 1 is quiet and efficient and not at all distracting ... You can't beat it for the price, under $2000 bucks with over a thousand dollars' worth of software. An Osborne and an Epson printer will put you in the computing/word-processing business cheaper than anything I can think of". BYTE stated "If you need a solid, well-supported, well-documented business system at a reasonable price, you should give [the Osborne 1] a great deal of consideration". The reviewer calculated that after subtracting $1530 for the retail price of the bundled software the price of the computer was "only $265 ... in a way you are getting a software package with a computer thrown in for (almost) free". He praised the quality of the documentation, and agreed with Pournelle that the screen's size did not cause difficulty. James Fallows agreed that the screen, although "the size of a postcard ... is much easier to read than that would suggest", and described the computer as "the best bargain on computer power in the business". In 1981, the daily Israeli newspaper Maariv, provided several Osborne 1 to its reporters. The computers were equipped with acoustic couplers. This configuration allowed a reporter to submit an article digitally directly from the field to the newsroom. Maariv used a localized version of Osborne 1 that supported Hebrew. Freelance journalist David Kline praised the Osborne 1's durability, reporting in 1982 that the "damage inflicted by arrogant customs officers, airport police, vengeful Paris bellhops and opium-fogged Pakistani cabbies were entirely cosmetic". Stating that a computer that weighs 30 pounds "really isn't very portable", Creative Computing in 1984 concluded that "the main reason that the Osborne was a success was not that it was transportable, but that it came with a pile of bundled software". References Further reading External links Osborne 1 At the Old Computer Museum Portable computers Personal computers Products introduced in 1981 Z80-based home computers Computer-related introductions in 1981

laptop Form Factor and Weight

Samsung Ativ Q The Samsung Ativ Q was a 13.3-inch convertible laptop to be manufactured by Samsung. Unveiled at a Samsung Premiere event on June 20, 2013, the tablet was to run Windows 8, but also shipped with software that also allowed it to run the Android operating system. The Ativ Q's hardware was also distinguished by multiple folding states and a high resolution display. Samsung announced that the Ativ Q would be released in the third quarter of 2013, with a representative indicating that it would be out in time for the back to school season. However, in August 2013, the South Korean edition of ZDNet reported that the release of the device would be indefinitely delayed due to patent issues relating to its Android emulation system: Samsung has not made any statements regarding the Ativ Q's release since. Specifications Hardware The Ativ Q's design incorporates a unique, rugged hinge (which also houses the CPU) that can be used to tilt the screen into a number of different positions, such as flipping it over entirely to use it like a stand, having it "float" above the keyboard on an angle, or in a traditional laptop-styled position. Due to the lack of space, a pointing stick is offered instead of a trackpad. The Ativ Q uses a 4th generation (Haswell), 2.6 GHz Intel Core i5 4200U processor with 4 GB of RAM. The device features at 13.3-inch capacitive touchscreen with a resolution of 3200×1800 at 275 ppi, and will also ship with an S Pen stylus. Software While Samsung's presentation showcased the Ativ Q running Windows 8.1, demo units of the Ativ Q at its launch event ran Windows 8. The Ativ Q was to ship with a stock version of Android 4.2.2 running inside a virtual machine, accessible from within the Windows environment. Shortcuts and a keyboard button are provided for switching to the Android environment, files can be shared between the two environments, and Android apps can also be pinned to the Windows Start screen. The Ativ Q is also bundled with Samsung's "SideSync" software for linking to and controlling other Samsung smartphones and tablets with Android. Release Although Samsung initially announced a late-2013 release in time for the back to school season, the South Korean edition of ZDNet reported in August 2013 that the Ativ Q's release would be delayed or cancelled due to patent issues surrounding its dual-OS functionality. In March 2014, it was reported that both Microsoft and Google were restricting devices from being shipped with both of their operating systems at once in order to protect their respective market shares and application ecosystems. Pressure from the companies had reportedly resulted in Asus discontinuing its line of similar Windows/Android dual-boot products, including the Transformer Book Duet, which was similarly left in a vaporware state. See also Vaporware References Ativ Q Tablet computers Convertible laptops Products introduced in 2013 Vaporware

laptop Form Factor and Weight

IdeaPad S series The IdeaPad S Series is a series of notebook computers launched by Lenovo in October 2008. The IdeaPad S10 was initially scheduled for launch in September, but its release was delayed in the United States until October. The S series began with the IdeaPad S10, the lowest cost model, powered by an Intel Atom processor in a 10.2-inch subnotebook. Later, more expensive laptops in the S-series also powered by Intel Atoms were released. Once the Atom CPU line was discontinued, the main line of lightweight S series laptops switched to alternatives, such as the low-power AMD A-series, Intel Celeron, Pentium, and low-cost versions of Y-series CPUs. 2008 The IdeaPad S10, the first laptop in the IdeaPad S Series of netbooks, was released in 2008. S10 The IdeaPad S10 was Lenovo's first netbook. While Engadget found the design unremarkable, the low starting price was well-received. The S10 featured a TFT active matrix 1024×576 or 1024×600 display with an 80 or 160 GB hard disk drive and 512 MB or 1 GB DDR2 Random Access Memory, both of which could be upgraded via a trap door on the bottom of the netbook. The initial S10 featured 512 MB of RAM soldered to system board with an expansion SO-DIMM slot for further upgrades to 2 or 2.5 GB (2.5 GB was only usable with an operating system with support for sparse memory regions). The processor was an Intel Atom that ran at 1.6 GHz. The S10 supported IEEE 802.11 b/g wireless networking and had two USB ports, an ExpressCard expansion slot, a 4-in-1 media reader, and a VGA output. These computers received positive consumer reviews and a 9/10 rating from Wired magazine. In May 2009 Lenovo introduced the S10-2. While the S10-2 shared many traits with the S10/S10e, it omitted the ExpressCard34 slot, featured a new physical design, added an additional USB port, and enlarged the keyboard, touchpad, and sizes of the hard drive and SSD. 2009 The IdeaPad S Series netbooks released by Lenovo in 2009 were the S10e, S10-2, and the S12. S10e The IdeaPad S10e was a re-launch of the IdeaPad S10, with features updated for the education market. The netbook included a quick start operating system and 5 hours of battery life at a low starting price. It weighed 2.8 lbs, with a form factor of 9.8 x 7.7 x 0.9–1.4-inches. The netbook offered a wide keyboard occupying almost the entire width of the chassis, and LAPTOP Magazine reported that it was easy for even adults to type on. S10-2 The IdeaPad S10-2 was a 10-inch netbook with a 1.6 GHz Intel Atom processor, 1GB RAM, a 6-cell battery, and Intel GMA Integrated Graphics. Notebook Review reported that the netbook's design offered "a cleaner and smoother appearance all around". The specifications of the netbook are as follows: Processor: Intel Atom N270 1.6 GHz or Intel Atom N280 1.66 GHz and Hyper-Threading RAM: 1GB DDR2 667 MHz Display: 10.1" (WSVGA, Glossy, LED-backlit, 1024x600) Storage: 160GB 5400rpm Graphics: Intel GMA 950 Integrated Wi-Fi: Broadcom 802.11b/g Card reader: 4-in-1 Dimensions: 10.2 x 7.6 x 0.7-1.8 (inches) Operating system: Windows XP Home Edition (SP3) S12 The IdeaPad S12 received a fairly positive review from PCMagazine. Its features that were well-received included the 12 inch widescreen with a 1280 x 800 resolution, keyboard, express card slot, and battery life. However, the netbook's price and weight were poorly received by the reviewers. The specifications of the netbook are as follows: Processor: Intel Atom N270 1.6 GHz RAM: 1GB (up to 3 GB) DDR2-667 Storage: 160GB 5400rpm SATA Display: 12.1" (1280x800) Graphics: Intel GMA 950 Wi-Fi: 802.11b/g Dimensions: 11.5 x 9.0 x 1.4 (inches) Weight: Operating system: MS Windows XP Home 2010 The IdeaPad netbooks released in 2010 were the S10-3, S10-3t, and S10-3s. S10-3 The IdeaPad S10-3 netbook was praised for its full-size keyboard, design, light chassis, and low price. It was criticized for its navigation experience, touchpad, low capacity hard drive, and the lack of options for customization. Michael Prospero from LAPTOP Magazine indicated in his review that Lenovo had addressed some of the issues raised about the S10-2 netbook and praised the keyboard and the design. He also indicated that the storage capacity was not on par with competitor offerings and that the touchpad could have been improved. S10-3t The IdeaPad S10-3t was a netbook that was also a convertible tablet. The S10-3t netbook was among the first computers to use the 1.83 GHz Intel Atom N470 processor. The software BumpTop was preloaded and offered a desk-like view of the desktop in 3D for ease of use. S10-3s The IdeaPad S10-3s was roughly an inch narrower than the S10-2, with a form factor of 10.6 x 6.6 x 1.4 inches. The netbook was also slightly lighter than similar netbooks and weighed 2.6 lbs. The netbook offered the following specifications: Processor: Intel Atom N450 1.66 GHz RAM: 1GB DDR2 Graphics: Intel GMA 3150 Storage: 160GB 5400RPM SATA Display: 10.1" (maximum resolution of 1024x600) 2011 The IdeaPad S Series netbooks released in 2011 were the S205 and the S215. S205 The S205 had an AMD Fusion E350 dual core processor, 11.6" widescreen display with a 16:9 aspect ratio, and ATI Mobility Radeon 6310M graphics. The specifications of the S205 are as follows: Processor: Up to 1.60 GHz AMD Dual-Core E-350 RAM: Up to 4GB DDR3 1066 MHz Graphics: Up to AMD Radeon HD 6310M (512 MB graphics memory) Dimensions (mm): 290 x 18~26.3 x 193 Weight: starting at 1.35 kg S215 The Lenovo IdeaPad S215 contained 500 GB, 5,400 RPM traditional HDD and 8 GB of solid-state storage. 2012 S300 Detailed specifications of the netbooks are as follows: Processor: several (ie: Celeron 887) RAM: 4GB Storage: SATA 500GB HDD Display: 14" Graphics: Intel GMA 950 Operating system: MS Windows 7 References External links IdeaPad S Series on Lenovo S

laptop Form Factor and Weight

Toshiba Pasopia 7 Toshiba Pasopia 7 (also known as PA7007) is a computer from manufacturer Toshiba, released in 1983 and only available in Japan. It was intended as the successor of the Toshiba Pasopia, offering improved sound and graphics. Graphic memory is increased to 48kb and two SN76489 sound chips are available, producing six five octave channels and two noise channels. The machine is partially compatible with the original Pasopia, and supports connecting cartridge-type peripherals. A new version of the operating system - T-BASIC7, is also available. This version is based on Microsoft BASIC and adds specific commands for this model, such as higher numerical precision or support for extra colors. Available peripherals for this model are a 5" disk drive, a Chinese characters ROM, a RS-232 interface and a printer. The keyboard is a full-stroke keyboard, JIS standard with a separated numeric keypad and some function keys. A latter model, Pasopia 700, is based on the Pasopia 7 and indented for a home learning system developed by Toshiba and Obunsha. Two disk-drives were added to the side of the main unit and the keyboard was separate. This machine was two cartridge slots (one at the front). Color palette The Pasopia 7 uses hardware dithering to simulate intermediate color intensities, based on a mix of the full intensity RGB primaries. This allows the machine to display 27 colors (3-level RGB). See also Toshiba Pasopia Toshiba Pasopia 5 Toshiba Pasopia IQ Toshiba Pasopia 16 References Pasopia Z80-based home computers Computer-related introductions in 1983

laptop Form Factor and Weight

BatteryMAX BatteryMAX is an idle detection system used for computer power management under operating system control developed at Digital Research, Inc.'s European Development Centre (EDC) in Hungerford, UK. It was created to address the new genre of portable personal computers (laptops) which ran from battery power. As such, it was also an integral part of Novell's PalmDOS 1.0 operating system tailored for early palmtops in 1992. Description Power saving in laptop computers traditionally relied on hardware inactivity timers to determine whether a computer was idle. It would typically take several minutes before the computer could identify idle behavior and switch to a lower power consumption state. By monitoring software applications from within the operating system, BatteryMAX is able to reduce the time taken to detect idle behavior from minutes to microseconds. Moreover, it can switch power states around 18 times a second between a user's keystrokes. The technique was named Dynamic Idle Detection and includes halting, or stopping the CPU for periods of just a few microseconds until a hardware event occurs to restart it. DR DOS 5.0 in 1990 was the first personal computer operating system to incorporate an idle detection system for power management. It was invented by British engineers Roger Alan Gross and John P. Constant in August 1989. A US patent describing the idle detection system was filed on 9 March 1990 and granted on 11 October 1994. Despite taking an early lead and having the protection of a patent, BatteryMAX did not enjoy significant commercial success having been sidelined after the disarray that followed the integration of Digital Research into Novell, Inc. in 1991. It was not until 1992, some three years after the invention, that software power management under operating system control became ubiquitous following the launch of Advanced Power Management (APM) by Microsoft and Intel. Functional overview BatteryMAX uses the technique of dynamic idle detection to provide power savings by detecting what the application is doing (whether it is idle), and switching power states (entering low power mode) therefore extending the battery life of the product. BatteryMAX employs a layered model of detection software encapsulated into an DOS character device driver called $IDLE$ that contains all the hardware-dependent code to support dynamic idle detection. It can either be linked into the DR-DOS operating system BIOS or loaded dynamically using the CONFIG.SYS DEVICE directive, overloading the built-in default driver. All versions of DR-DOS since version 5.0 have contained dynamic idle detection support inside the operating system kernel. When the operating system believes an application is idle, it calls the $IDLE$ BIOS/driver layer, which executes custom code written by the computer manufacturer or third parties to verify the request and switch power states. Using the device driver concept, BatteryMAX can be integrated with hardware-related power management facilities, which might be provided by the underlying hardware, including interfacing with APM or ACPI system BIOSes. Power states are computer dependent and will vary from manufacturer to manufacturer. Power savings can be made in a number of ways including slowing/stopping the processor clock speed or shutting off power to complete sub-systems. Before switching power states, the $IDLE$ driver uses any available hardware assistance to detect if the application has been accessing other components in the system. For example, the application may be polling a serial port, or updating a graphics screen. If this is the case, the device driver determines that the application is not in fact idle and overrides the kernel's call to switch power states by passing information back up the layers and allowing application execution to resume. COMMAND.COM in DR DOS 5.0 and higher implements an internal command IDLE taking ON|OFF parameters to enable or disable the dynamic idle detection. Detecting when an application is idle An application is idle if it is waiting for some external event to occur, for example for a keystroke or a mouse movement, or for a fixed amount of time to pass. The DR-DOS kernel monitors all DOS API calls building up a profile of the applications behavior. Certain combinations of API calls suggest that the application is idle. The $IDLE$ driver is able to make the subtle distinction between a program that is genuinely idle, for instance one that is polling the keyboard in a tight loop, and one that is active but also polling the keyboard, to test for an abort key to be pressed. The driver makes this distinction by monitoring the time taken to go idle. If the time is within a specified period, the driver assumes that the program is idle, e.g. polling in a tight loop for a key to be pressed. If the time is outside the specified limit, the driver assumes that some processing has occurred in between polling the keyboard, and allows application execution to resume without switching power states. A local variable, IDLE_CNTDN, specifies the time against which the actual time taken to go idle is compared. The value for this variable is dynamically calculated at initialization and recalculated periodically. Origins of BatteryMAX The idle detection technique was first used to improve multi-tasking of single-tasking DOS applications in Digital Research's multi-tasking/multi-user Concurrent DOS 386 (CDOS386) operating system. Programs written for single-tasking operating systems such as MS-DOS/PC DOS can go into endless loops until interrupted; for example when waiting for a user to press a key. Whilst this is not a problem where there is no other process waiting to run, it wastes valuable processor time that could be used by other programs in a multi-tasking/multi-user environment like CDOS386. Applications designed for a multi-tasking environment use API calls to "sleep" when they are idle for a period of time but normal DOS applications do not do this so idle detection must be used. The Concurrent DOS 386 release included an Idle Detection function in the operating system kernel which monitored DOS API calls to determine whether the application was doing useful work or in fact idle. If it was idle, the process was suspended allowing the dispatcher to schedule another process for execution. Patent litigation BatteryMAX and the "idle detection" patent played an important role in an alleged patent infringement relating to software power management under operating system control. On 15 May 2009, St. Clair Intellectual Property Consultants. filed civil action No. 09-354 in the United States District Court D. Delaware, against defendants Acer, Dell, Gateway and Lenovo and on 18 September 2009 filed civil action No. 09-704 against Apple, and Toshiba The actions alleged infringement of several U.S. patents that they owned relating to software power management under operating system control. St. Clair asserted that Henry Fung had invented software power management under operating system control and alleged that these companies had infringed St. Clair's patents and therefore owed St. Clair royalty payments. Microsoft intervened on behalf of the defendants and filed a declaratory judgment against St. Clair on 7 April 2010, seeking judgments of non-infringement and invalidity of the Fung patents. (D.I. 1, C.A. No. 10-282). Intel filed an intervention on behalf of the defendants and this was granted on 4 June 2010 (D.I. 178, C.A. No. 09-354). Seattle law firm Perkins Coie, acting for the defendants, discovered BatteryMAX and Gross's idle detection patent during a prior art search. Gross's patent had an earlier priority date than Fung's patents which if proven would undermine St. Clair's case. On 28 February 2011, Gross was hired by Intel as a subject matter expert to provide expert witness testimony for the defendants in the case. Gross provided evidence in his expert report that he, not Fung, had invented software power management under operating system control and sited the Idle Detection patent and the existence of BatteryMAX as proof of this. St. Clair filed a motion to exclude opinions concerning BatteryMAX, in an attempt to have Gross's expert report dismissed, but on 29 March 2013, the district court denied St. Clair's motion declaring Gross's testimony for the defendants as admissible, stating that "The Court agrees with Defendants that there is sufficient corroborating evidence that BatteryMAX was available to the public prior to the Fung patents' priority date. Further, the Court concludes that even if BatteryMAX did not predate the Fung patents, Mr. Gross's testimony […] would be relevant and helpful to the fact finder in an obviousness inquiry”. See also Advanced Power Management (APM) Advanced Configuration and Power Interface (ACPI) References External links DOS technology Digital Research Battery (electricity)

laptop Battery Life

Smart battery A smart battery or a smart battery pack is a rechargeable battery pack with a built-in battery management system (BMS), usually designed for use in a portable computer such as a laptop. In addition to the usual positive and negative terminals, a smart battery has two or more terminals to connect to the BMS; typically the negative terminal is also used as BMS "ground". BMS interface examples are: SMBus, PMBus, EIA-232, EIA-485, and Local Interconnect Network. Internally, a smart battery can measure voltage and current, and deduce charge level and SoH (State of Health) parameters, indicating the state of the cells. Externally, a smart battery can communicate with a smart battery charger and a "smart energy user" via the bus interface. A smart battery can demand that the charging stop, request charging, or demand that the smart energy user stop using power from this battery. There are standard specifications for smart batteries: Smart Battery System, MIPI BIF and many ad-hoc specifications. Charging A smart battery charger is mainly a switch mode power supply (also known as high frequency charger) that has the ability to communicate with a smart battery pack's battery management system (BMS) in order to control and monitor the charging process. This communication may be by a standard bus such as CAN bus in automobiles or System Management Bus (SMBus) in computers. The charge process is controlled by the BMS and not by the charger, thus increasing security in the system. Not all chargers have this type of communication which is commonly used for lithium batteries. Besides the usual plus (positive) and minus (negative) terminals, a smart battery charger also has multiple terminals to connect to the smart battery pack's BMS. The Smart Battery System standard is commonly used to define this connection, which includes the data bus and the communications protocol between the charger and battery. There are other ad-hoc specifications also used. Hardware Smart battery controller integrated circuits are available. For example, Linear Technology manufactures the LTC4100 and the LTC4101 Smart Battery System-compatible products. Microchip Technology provides an application note for a smart battery charger based on the PIC16C73. The PIC16C73 source code is available for this application. See also Battery charger CMOS battery Rechargeable battery References Smart devices Rechargeable batteries Battery charging

laptop Battery Life

Acer Aspire Timeline Aspire Timeline is a series of notebook computers manufactured by Acer Inc. designed to achieve battery life in excess of eight hours with ultrathin designs. The first generation Acer Timeline models use Intel's ultra low voltage (ULV) processors and Intel's Laminar Wall Jet technology. Aspire Timeline There are six Aspire Timeline models: Aspire 1810T, Aspire 1810 Olympic Edition, Aspire 3810T, Aspire 4810T, Aspire 4810 Olympic Edition, Aspire 5810T. Aspire TimelineX In 2010, Acer launched a new Aspire TimelineX series that employ Intel Core processors. The nine – cell battery model is claimed by the company to last up to 12 hours. Aspire TimelineX (2010) models: Aspire 3820T Aspire 4820T Aspire 5820T Aspire 3820TG Aspire 4820TG Aspire 5820TG In April 2011, Acer released the third generation of Timeline models in Taiwan which sport the Intel's Sandy Bridge processor. ''Aspire Timeline X (2011) lineup: 3830T The 3830T has two versions: a Core i3-2310M and Core i5-2430M. It measures 13.3 inches and has a 1366×768 LED backlit LCD, Intel HD Graphics 2000/3000, 500/750GB hard drive for storage, 4/6GB DDR3 RAM and 3 USB ports, and weighs 4.08 pounds. 4830T The 4830T contains the Core i5-2430M. It measures 14 inches and has a 1366×768 LED backlit LCD, Intel HD Graphics 3000, 640GB hard drive for storage, 4/6GB DDR3 RAM and 3 USB ports, and weighs 4.78 pounds. 5830T The 5830T contains the Core i5-2450M. It measures 15.6 inches and has a 1366×768 LED backlit LCD, Intel HD Graphics 3000, 750GB hard drive for storage, 6GB DDR3 RAM and 3 USB ports, and weighs 5.49 pounds. 3830TG The 3830TG has several versions: a Core i3-2330M, a core i5-2410m, a Core i5-2430M and a Core i7-2620m. It measures 13.3 inches and has a 1366×768 LED backlit LCD, NVIDIA GeForce GT540M graphics and an Intel Hd 2000/3000, it switches between the two using Nvidia's Optimus technique. A 500GB hard drive for storage, 4GB DDR3 RAM and 3 USB 2.0 ports, of which are USB 2.0 and one of them being a 3.0 port that can be used to charge external devices when the laptop is turned off. It also features Kenwood's Dolby Home Theater speakers and weighs 4.12 pounds. 4830TG The 4830TG same specification as above (except for Core i3-2330M). It measures 14 inches and weighs 4.67 pounds, contains DVD super multi DL drive (this is not present in the 3830TG). It has a 640GB hard drive for storage. For connectivity and port, you'll find Bluetooth® 2.1+EDR, one faster USB3 port, microphone in, 3.5mm audio jacks for headphone out, memory card reader ( SD Card, Memory Stick, Memory Stick PRO, MultiMediaCard, xD-Picture Card, SDXC Memory Card ), HDMI port, VGA port, Gigabit Ethernet LAN with RJ connector and 802.11 b/g/n wireless for internet connections. 5830TG The 5830TG has the same specification as above (except for the 3830TG version which runs on Core i3-2330M). Its screen is 15.6 inches and weighs 5.49 pounds, It contains DVD super multi DL drive (this is not present in the 3830TG). Acer Aspire Timeline Ultra family In 2012, Acer introduced the new Aspire M3 of the Timeline Ultra family The Acer Aspire Timeline Ultra series is slim and light, just 20 mm thin. It has a 15.6-inch display and weighs less than five pounds. It was first shown at the Consumer Electronics Show (CES) in Las Vegas in January 2012, then in March at the CeBIT tradeshow in Hannover, Germany. The Aspire Timeline Ultra M3-581TG contains an Intel Core i7-2637M ULV processor, up to 6GB of RAM. Reception The Acer Aspire line was generally well received. Some models such as the Aspire 3820T were awarded by the international press. See also Acer Aspire Acer TravelMate References External links Acer Timeline Official Website Acer Inc. laptops

laptop Battery Life

PowerTOP PowerTOP is a software utility designed to measure, explain and minimise a computer's electrical power consumption. It was released by Intel in 2007 under the GPLv2 license. It works for Intel, AMD, ARM and UltraSPARC processors. PowerTOP analyzes the programs, device drivers, and kernel options running on a computer based on the Linux and Solaris operating systems, and estimates the power consumption resulting from their use. This information may be used to pinpoint software that results in excessive power use. This is particularly useful for laptop computer users who wish to prolong battery life, and data center operators, for whom electrical and cooling costs are a major expenditure. Usage The original focus was on CPU sleep states, and showing the programs or drivers responsible for "wakeups" which prevent CPUs entering sleep states. A database of known problems automatically provides more user friendly "tips" for specific sources of wakeups. However, it also shows information on CPU frequency scaling. Over time the database has been expanded to include tips on a wide range of power consumption issues. Hardware It is most effective on laptop computers. Laptops are specifically designed to allow power use to be both monitored and controlled. In particular, many laptop computers can measure the rate of battery use (when not connected to mains power). PowerTOP uses this feature to estimate power usage in watts and battery life. This provides immediate feedback on changes made e.g. disabling wireless networking when not used. Project activity The latest release of PowerTOP (version 2.14) was made public on April 15, 2021. The project is hosted on GitHub. See also Power management Green computing LatencyTOP top (software) Run-time estimation of system and sub-system level power consumption References External links Version Control Repository Powertop for OpenSolaris – part of Project Tesla Linux process- and task-management-related software Computers and the environment

laptop Battery Life

Notebook processor A notebook processor is a CPU optimized for laptops. One of the main characteristics differentiating notebook processors from other CPUs is low-power consumption, however, they are not without tradeoffs; they also tend to not perform as well as their desktop counterparts. The notebook processor is becoming an increasingly important market segment in the semiconductor industry. Notebook computers are an increasingly popular format of the broader category of mobile computers. The objective of a notebook computer is to provide the performance and functionality of a desktop computer in a portable size and weight. Cell phones and PDAs use "system on a chip" integrated circuits that use less power than most notebook processors. While it is possible to use desktop processors in laptops, this practice is generally not recommended, as desktop processors heat faster than notebook processors and drain batteries faster. Models Current ARM architecture (used in Chromebooks, Windows 10 laptops, Linux netbooks and recent Macs) Apple M series MediaTek Nvidia: Tegra Qualcomm: Snapdragon Rockchip Samsung Electronics: Exynos x86 AMD: Ryzen, Athlon, and A-Series APU Intel: Xeon mobile, Core, Pentium, and Celeron Former PowerPC Motorola and Freescale Semiconductor made PowerPC G4 processors for the pre-Intel Apple Computer notebooks. x86 Transmeta: Crusoe and Efficeon Intel: Pentium M AMD: Mobile Athlon II, Mobile Athlon 64, Mobile Sempron Image gallery See also Computer architecture Microprocessor Personal computing References Laptops Microprocessors Mobile computers

laptop Battery Life

Run-time estimation of system and sub-system level power consumption Electronic systems’ power consumption has been a real challenge for Hardware and Software designers as well as users especially in portable devices like cell phones and laptop computers. Power consumption also has been an issue for many industries that use computer systems heavily such as Internet service providers using servers or companies with many employees using computers and other computational devices. Many different approaches (during design of HW, SW or real-time estimation) have been discovered by researchers to estimate power consumption efficiently. This survey paper focuses on the different methods where power consumption can be estimated or measured in real-time. Measuring real time power dissipation is critical in thermal analysis of a new design of HW like processors (CPU) just as it is important for OS programmers writing process schedulers. Researchers discovered that knowing the real-time power consumption on a subsystem level like CPU, hard drives, memory and other devices can help power optimizations in applications such as storage encryption, virtualization, and application sandboxing, as well as application tradeoffs. Different technologies have been discovered that can enable measuring power consumption in real-time. They can be ranked in two main categories: direct measurement using subsystem power sensors and meters or indirect estimation based on provided information like temperature or performance counters. There are also different methods within each category; for example, different models are discovered to use performance counters for power estimation. Each one of these methods has its own benefits and disadvantages. The goal of this paper is to survey that different methods in each category. Run-time Estimation of System and Sub-system Level Power Consumption Power consumption can be different for the same type of system because of differences in manufacturing of Hardware and in temperature conditions in which the device is going to operate. Real-Time power management can be used to optimize the system or subsystems to minimize the energy consumption which may, for example, extend the battery lifetime of mobile devices or result in energy savings for Internet companies operating with many computer servers. The following sections are technologies discovered to enable real-time power estimation. Indirect Power measurement Indirect power measurement such as using a CPU performance monitoring unit (PMU), or performance counters to estimate run-time CPU and memory power consumption are widely used for their low cost. Performance counters Hardware performance counters (HPCs) are a set of special purpose registers built into modern microprocessors to store the counts of hardware-related activities for hardware and software related events. Different models of processors have limited numbers of hardware counters with different events that will satisfy the CPU requirement. These performance counters are usually accurate and provide important detailed information about processor performance at the clock cycle granularity. Researchers were able to create different models that use the HPCs event to estimate the system power consumption in real-time. First-order, linear power estimation model using performance counters The first-order linear model was developed by G. Contreras and M. Martonosi at Princeton University using Intel PXA255 processor to estimate CPU and memory power consumption. This is distinct from previous work that uses HPCs to estimate power because the Intel PXA255 processor power requirement was tighter and it offered fewer available performance events compared to mid and high-end processors. This method is also not tied to specific processor technology and HPCs layout for power estimation but rather can be used for any type of processor with HPCs. This linear power model uses five performance events as follows: Instruction Executed, Data Dependencies, Instruction Cache Miss, Data TLB Misses, and Instruction TLB Misses. A linear model expression is derived (equation 1) as follows assuming a linear correlation between performance counters values and power consumption. (1) Where, are power weights and is a constant for processor power consumption during idle time. One can also estimate power consumption of memory (external RAM) by tracking the performance events if they are available on the designed processor. PXA255 processor, for example, does not have direct performance events accounting for external RAM but Instruction Cache Miss, Data Cache Miss, and Number of Data Dependencies on processor can be used to estimate the memory power consumption. Again, a linear model is derived from the given information (equation 2) to estimate the memory power consumption. (2) Where, are power weights and is a power consumption constant during idle time. The main challenging issue with this method is computing the power weights using a mathematical model (ordinary Least Squares Estimation) at different voltage/frequency points. These constant values in equations 1 and 2 are voltage and frequency depends and they must be computed during benchmark testing. After building such a table for the power weights parameters, then the table can be implemented in software or hardware to estimate the real-time power. The other challenge is in accessing HPCs; for example, in this case they are being read at the beginning of the main OS timer interrupt which requires a software modification. A software program can be written using the equations 1 and 2 and the estimated power weights derived from the table to estimate the power consumption at run-time. For equation 1 the program also needs 5 samples of HPCs but in this example the PXA255 processor can only sample 2 events at any given time therefore multiple code execution is required as well as aligning the data. In summary, the main benefits of this approach are that it is easy to implement, low cost, and does not require special hardware modification. Software designers can benefit from this model by having a quick power estimate for their applications without any extra hardware requirement. The main disadvantage of this method is that: real world processors are not perfect and this model does not account for non-linear relationships in those processors. Another issue is also the software overhead running on the processor that consumes power. This approach also does not provide detailed information about power consumption in each architectural functional unit so designers can not see the difference between each module by executing different parts of the software. This method can not be used by OS scheduler or software developers executing multi threaded programs because it needs to gather data by running benchmarks several times. This work is also good for single core processors but not multi-core processors. Piece-wise linear power estimation model using performance counters The piece-wise model was developed to estimate power consumption accurately using performance counters. This method was developed by K.Singh, M.Bhadauria at Cornell University and S.A.McKee at Chalmers University of Technology independently of program behavior for SPEC 2006, SPEC-OMP and NAS benchmark suits. This method was developed to analyze the effects of shared resources and temperature on power consumption for chip multiprocessors. This method used 4 performance counters of AMD Phenom processor. The performance counters are as follows: : L2_CACHE_MISS: ALL, : RETRIED_UOPS, : RETIRED_MMX_AND_FP_INSTRUCTIONS: ALL, : DISPATCH_STALLS. These performance counters are architecturally specific to AMD Phenom and may be different for other processors. AMD allows collecting data from those four HPCs simultaneously. A microbenchmarks, which is a small program, attempts to collect data from the above selected HPCs. Collected data on each processor core are used in the following equation. (3) Where (4) Equation 4 transformation can be linear, inverse, logarithmic, exponential, or square root; it depends on what makes the power predication more accurate. Piece wise linear function was chosen to analyze equation 4 from collected data because it will capture more detail about each processor core power. Finally, analyzing the collected HPCs data with piece wise linear method gives the detailed power consumption (for example, L2 cache misses has the highest contribution in power consumption versus L3). The above method was used to schedule each AMD Phenom processor core in a defined power envelope. The processors core gets suspended when the core exceeds the available power envelope and it becomes available again when enough power becomes available. There are some restrictions and issues with this method; for example, this method does not account for temperature effect. There is a direct relationship between temperature and total power consumption (because as temperature increases the leakage power goes up) that this model does not account for because AMD Phenom does not have per-core temperature sensors. A second disadvantage is that mictobenchmarks is not complete to get a better power estimate (for instance, it does not cover the DISPATCH_STALLS HPC). A more complete microbenchmark will cause timing issues. Future work needs to be done to incorporate thermal data into the model and thread scheduling strategies as well as to reduce frequency (DVFS) of each core versus suspending the core. This method only covers processors but there are other subsystems, like memory, and disks, that also need to be considered in total power. This method is different from many other methods using performance counters because all the cores in multi core processors are considered, the performance counters being used do not individually have high effect with power consumption and it estimates the power consumption for each core that can be used for real time scheduling of each core to be under power envelope. Adaptive power estimation model using performance counters Most models like the above do not have the capability to measure power consumption at a component or subsystem level. DiPART (Disaggregated Power Analysis in Real Time) developed by Professor M. Srivastava, Y. Sun, and L. Wanner at University of California, Los Angeles enables this capability to estimate power consumption based on hardware performance counters and using only one power sensor for the whole system. Models are required to estimate power consumption based on performance counters. These models correlate the data for different performance counters with power consumption and static models like above examples (First-order and Piece-wise linear) have different estimation errors due to variations across identical hardware. DiPART is a solution to this problem because it is a self-adaptive model that can be calibrated once and be applied across different platforms. The linear estimation model for DiPART requires a power sensor capable of acquiring dissipated power consumption and current measurement at run time. There are different embedded sensors like Atom-LEAP system or Qualcomm's Snapdragon Mobil Development Platforms that can do the job for DiPART. One single power sensor can be used to calibrate the subsystem level estimation model DiPART. Total power of the system is the summation of the power consumption by each subsystem shown in equation 5. (5) For each subsystem, power performance counters are being used. For CPU power, ten performance counters are required as follows: Task counts, Context Switch counts, CPU Migration counts, Page Fault counts, Cycles counts, Instruction counts, Branches counts, Cache Refer counts, and Cache Miss Counts. Then a linear model is used to compute the total power of CPU and coefficient values are computed with a liner regression algorithm using performance counter data and monitored power consumption data. (6) The above performance counters can also be used for RAM power consumption model and the memory coefficient vector and the constant value is also computed during training phase with performance counter data and monitored power consumption data. (7) Disk power consumption model is based on input counter and output counter correlated with Input/Output events counters. The same approach is taken as for CPU and RAM to estimate the coefficient and constant for disk power during training phase. (8) During training the total power measured from the sensor is subtracted from the initial CPU, RAM, and Disk power model predication. Then 10% from the delta result is taken to compensate in individual subsystems CPU, RAM and disk models. This iteration will continue until estimation error for total system power is smaller than some threshold, or it hits the specified number of iterations. During this training process with some number of iteration process each subsystem model gets adjusted accordingly base on the delta percentage. Once the subsystems are trained the total system does not need to be trained. The CPU, RAM, and Disk power model modification and system-level variation is required if the total delta is not less than 10%. The iteration process will continue until the individual subsystem power model prediction gets close to the monitored total power. When subsystem power consumption model has been trained the total system level power consumption model does not need to train again for the same system. This method is beneficial compared to static models because of its adaptability to the variations among different systems even with exactly the same hardware. The experimental results show that estimated errors are high before training the DiPART, and that the error decreases as the number of iteration increases. One major issue with this model is the dependency on power sensors to measure the total power. The other issue is the number of performance counters being used for DiPART model. These performance counters might not be available for all processors. This method was also used for CPU, RAM and disk subsystem but there are other subsystems that need to be considered in total power consumption. The main problem with adding more subsystems will be the adaptive mechanism because as the number of subsystems increases, the accuracy and training speed will decrease. Another issue is that the CPU, Disk and RAM are also not perfect and have some non-linearity part that was not considered in this method. Dynamic Thermal Management As the Integrated Circuit (IC) technology size is getting smaller in nanometer scale and more transistors are put together in that small area, the total power and temperature on chip are also increasing. The high temperature on the chip, if not controlled, can damage or even burn the chip. The chip high temperature also has impacts on performance and reliability. High chip temperature causes more leakage power consumption, higher interconnect resistance and slower speed of transistors. Therefore, Dynamic Thermal Management (DTM) is required for high performance embedded systems or high-end microprocessors. Thermal sensors are also not perfect for the job because of their accuracy and long delay to capture the temperature. The DTM idea is to detect and reduce the temperature of hot units spots in a chip using different techniques like activity migration, local toggling, dynamic voltage and frequency scaling. A new method was developed by H. Li, P. Liu, Z. Qi, L. Jin, W. Wu, S.X.D Tan, J. Yang at University of California Riverside based on observing the average power consumption of low level modules running typical workload. There is a direct correlation between the observation and temperature variations. This new method was a solution to replace the old technologies such as on-line tracking sensors on the chip like CMOS-based sensor technology that are less accurate and requires hardware implementation. This method is based on observing the average power in a certain amount of time which determines the temperature variations. This idea can be implemented with a fast run-time thermal simulation algorithm at architectural level. This method also presents a new way to compute the transient temperature changes based on the frequency domain moment matching concept. The moment matching concept is basically said that the transient behaviors of a dynamic system can be accurately described by a few dominant poles of the systems. The moment matching algorithm is required to compute the temperature variation response under initial temperature conditions and average power inputs for a given time. This method also follows circuit level thermal RC modeling at the architectural level as described in reference. The unit temperature variation during run-time is because of the irregular power trance generated by each unit in their architectural blocks. This power input is consistent of DC and small AC oscillation. It was also shown and proven that most of the energy in the power trace concentrates on the DC component. Therefore, the average power can be described as a constant DC input to thermal circuit. After all a thermal moment marching (TMM) with initial condition and DC input is required to be implemented. The TMM model is as follows: (9) G and C are conductive and capacitive circuit matrices, and x is the vector of node temperature. u is the vector of independent power source and B is the input selector matrix. This equation will be solved in frequency domain and the initial condition is required which will be the initial temperature at each node. The main idea is to implement the TMM algorithm which provides better reliable on-line temperature estimation for DTM applications. In summary, the TMM algorithm is much faster than the previous work in this area to estimate the thermal variation because this method is using frequency domain moment matching method. The other work (like HotSpot) uses the integration method where it needs all previous points to obtain the temperature at certain running point. This will make the simulation time longer. This work can also be improved by computing the average power real-time using performance counters. This method can be added to the above models using performance counters to estimate on the fly temperature variation as the programs are getting executed. PowerBooter and PowerTutor This power model technique was developed by collaboration between L. Zhang, B. Tiwana, Z. Qian, Z. Wang, R.P. Dick, Z.Mao from University of Michigan and L. Yang from Google Inc. to accurately estimate power estimation online for Smartphones. PowerBooter is an automated power model that uses built-in battery voltage sensors and behavior of battery during discharge to monitor power consumption of total system. This method does not require any especial external measurement equipment. PowerTutor is also a power measurement tool that uses PowerBooter generated data for online power estimation. There is always a limitation in Smartphone technology battery life span that HW and SW designers need to overcome. Software designers do not always have the best knowledge of power consumption to design better power optimized applications therefore end users always blame the battery lifespan. Therefore, there is a need for a tool that has the capability to measure power consumption on Smartphones that software designers could use to monitor their applications in real-time. Researchers have developed specific power management models for specific portable embedded systems and it takes a huge effort to reuse those models for a vast variety of modern Smartphone technology. So the solution to this problem is PowerBooter model that can estimate real-time power consumption for individual Smartphone subsystems such as CPU, LCD, GPS, audio, Wi-Fi and cell phone communication components. Along with PowerBooter model an on-line PowerTutor utility can use the generated data to determine the subsystem level power consumption. The model and PowerTutor utility can be used across different platforms and Smartphone technologies. This model is different from the other models discovered because it relies only on knowledge of the battery discharge voltage curve and access to battery voltage sensor which is available in all modern Smartphones. The basic idea for this model technique is to use battery state of discharge with running training software programs to control phone component power and activity states. Each individual Smartphone component is held in a specific state for a significant period of time and the change in battery state of discharge is captured using built-in battery voltage sensors. The first challenging idea is to convert battery voltage readings into power consumption. This is determined by state of discharge (which is total consumed energy by battery) variation within a testing interval captured by voltage sensors that will eventually drive the following equation. (10) Where E is the rated battery energy capacity and SOD (Vi) is the battery state of discharge at voltage Vi and P is the average power consumption in the time interval t1 and t2. The state of discharge can be estimated using look up table where the relationship between present voltage and SOD is captured. Determining the energy is also an issue because the energy is changing as the battery gets old. The new batteries have the total energy written on their back but the value can not be true for all time. It can estimate the energy at highest and lowest discharge rate to decrease the error. The internal resistance also has significant impact on the discharged current. To decrease the effect of internal resistance all the phone components can be switched to their lowest power modes to minimize the discharge current when taking a voltage reading. Finally, this method uses a piece-wise linear function to model the non-linear relationship between SOF and battery voltage. The above battery model can be all automated with 3 steps which are described in. In conclusion, this method is beneficial because all Smartphones can use this method and for new Smartphones this model needs to be constructed only once and after automating the process there would be no need for any extra equipment to measure power consumption. Once the model is generated automatically or manually the PowerTutor utility can use the data to estimate power consumption in real time. Software engineers can use this utility to optimize their design or users can use this tool to make their decision about buying applications based on the power consumption. The main issues are in computing the energy which adds up to accuracy of the power model. Another issue is also considering the internal resistor to read the voltage. This can be resolved in newer versions of Smartphones that provide current measurement instead of voltage. The above model needs to be modified using the current measurement. Appscope and DevScope are similar work to estimate Smartphone power consumptions. Run- time modeling and estimation of operating system power consumption The operating system (OS) is the main software running on most computing systems and contributes a major component in dissipating power consumption. Therefore, operating system model was developed by T. Li and L.K John from University of Texas at Austin to estimate the power consumption by OS that helps power management and software applications power evaluation. It has been computed that software execution on hardware components can dissipate a good portion of power consumption. It is also been shown that the choice of algorithm and other higher level software code decisions during the design of software could significantly affect system power. Many of these software applications rely on operating system; therefore, overlooking the estimated power consumption by OS could cause huge error in energy estimation. Estimating OS power consumption could help software designers optimize their code design to be more energy efficient. For example, software engineer; can observe the power consumption when using different compiling techniques to handle TLB misses and paging. A good OS model needs to have the following properties to be good enough for thermal or power management tools. The model needs to be highly reliable, fast, and it also should have run-time estimation capability that does not increase overhead. The model should be simple and easily adoptable across different platforms. The purposed run-time power estimation requires a first order linear operation on a single power metric, reducing estimation overhead. The Instruction per Cycle (IPC) can be used as the metric to characterize the performance of modern processors. In paper shows how various components in the CPU and memory systems contributes to the total OS routine power. Data-path and pipeline structure along with clocks are consuming the most power. A linear model can be derived from IPC that tracks the OS routine power. A simple Energy equation can be used to estimate a given piece of software energy consumption, where P is the average power and T is the execution time of that program. The challenging part is to compute the average power P for each individual routine of operation system. One can use the correlation between IPC and OS routine average power or hardware performance counters can be used. The profiling method (data gathered from benchmark testing) can also be used to predict the energy consumption. The linear power model in is as follows:. This is a simple linear model that shows a strong correlation between IPC and OS routine power. In this approach profiling is also required to generate data needed to build the model. After the model is generated for one system, then it is not needed again for the same system. Virtual Machine Power Metering and Provisioning Joulemeter is a proposed solution by Aman Kansal, Feng Zhao, and Jie Liu from Microsoft Inc. and Nupur Kothari from University of Southern California, Los Angeles and Arka Bhattacharya from Indian Institute of Technology to measure virtual machine power which cannot be measured directly in hardware. This method is used for power management for virtualized data centers. Most servers today have power metering and the old servers use power distribution units (PDUs). This method uses those individual power meters to save significant reduction in power provisioning costs. This method uses power models in software to track VM energy usage on each significant hardware resource, using hypervisor-observable hardware power states. Joulemeter can also solve the power capping problem for VMs which will reduce power provisioning costs significantly. The largest power consuming subsystems in computer servers are the processor, memory and disk. Servers also have idle energy consumption which sometimes can be large, but it is static and it can be measured. Power models are presented for each of subsystems CPU, memory and disk in reference in detail. This power model is the core technique for Joulemeter. Figure 4 in reference shows the block diagram of Joulemeter where System Resource & Power Tracing module reads the full server CPU, disk and power usage. The VM resource tracking module tracks all the work load using hypervisor counters. The base model training module implements the learning methods described in as well as refinement module. The energy calculation module finally takes the out of base model training module and model refinement module to output the VM energy usage using the energy equations described in reference. The benefits of this method are safe isolation of co-located workloads, enabling multiple workloads to be consolidated on fewer servers, resulting in improved resource utilization and reduced idle power costs. Joulemeter can also be used to solve the power capping problem for VMs which will saved significant amount of power provisioning costs in data centers. Direct Power measurement One can use different types of sensors to gather voltage, current, frequency or temperature and then use those data to estimate power consumption. Low Power Energy Aware Processing embedded sensor system The LEAP (Low Power Energy Aware Processing) has been developed by D. McIntire, K. Ho, B. Yip, A. Singh, W. Wu, and W.J. Kaiser at University of California Los Angeles to make sure the embedded network sensor systems are energy optimized for their applications. The LEAP system as described in reference offers a detailed energy dissipation monitoring and sophisticated power control scheduling for all subsystems including the sensor systems. LEAP is a multiprocessor architecture based on hardware and software system partitioning. It is an independent energy monitoring and power control method for each individual subsystem. The goal of LEAP is to control microprocessors to achieve the lowest per task operating energy. Many modern embedded networked sensors are required to do many things like image processing, statistical high performance computing and communication. To make sure all of these applications are working efficiently a real-time energy monitoring and scheduling feature is required and LEAP can offer this feature for those systems. LEAP (ENS) system was designed to offer high accuracy and low overhead energy measurement capability. LEAP enables energy aware applications through scheduling and energy profiling of high energy efficiency components including multiple wireless network interfaces, storage elements, and sensing capabilities. The biggest advantage of LEAP system is its Energy Management and Preprocessing (EMAP) capability. The experimental results shows that the optimal choice of sensor systems, processor, wireless interface, and memory technology is not application dependent but it could be hardware allocation issue. EMAP has the capability to partition devices into many power domains with the capability to monitor, enable or disable power to each domain, as well as to respond to trigger events or conditions that restore or remove power in each domain. EMAP collects data periodically and transfers them to the host process and power management schedule is then provided by host processor to EMAP. Figure 1 in reference shows the LEAP architecture and EMAP architecture. The LEAP and EMAP are complex platforms which require hardware and software. All of the detailed design approaches are described in reference. In conclusion, LEAP differs from previous methods like PowerScope because it provides both real-time power consumption information and a standard application execution environment on the same platform. As a result, LEAP eliminates the need for synchronization between the device under test and an external power measurement unit. LEAP also provides power information of individual subsystems, such as CPU, GPU and RAM, through direct measurement, thereby enabling accurate assessments of software and hardware effects on the power behavior of individual components. Power model validation through thermal measurements One of the challenges for HW or SW designers is to validate their simulation data with empirical data. They require some type of utility or tool to measure power consumption and compare with their simulation data. One of these methods to capture real time data to validate power or thermal models is an infrared measurement setup developed by F.J. Mesa-Martinez, J.Nayfach-Battilana and J. Renau at University of California Santa Cruz. Their approach is to capture thermal maps using infrared cameras with high spatial resolution and high frame rate. Then a genetic algorithm finds a power equation for each floorplan block of processor that produces the capture thermal map to give detailed information about power breakdown (leakage and dynamic). They also developed an image processing filter to increase the thermal image accuracy. The biggest challenge for this approach is to obtain a detailed power map from the thermal measurements. There is no direct mapping between measured information and power. A genetic algorithm was developed described in reference that iterates multiple thermal traces and compares them with the results from thermal simulator to find the best power correlation. The first step is to measure the temperature using IR camera and within the oil coolant that flows over the top of the chip surface, the detailed setup information is described in reference. Oil is chosen because of ease in modeling and accuracy. The infrared cameras must be calibrated to compensate for different material thermal emissions, lens configurations, and other factors in reference. A second filter is also applied to compensate for the optical distortion induced by lens setup. A very accurate thermal model is required in this approach to account for effects of the liquid cooling setup accurately. The model equations are described in reference. Designers can use this method to validate their simulation or optimize their design especially because this method provides the breakdown information about leakage and dynamic power consumption. This method is also helpful in chip packaging design, heat sink, and cooling system. This method also shows designers which part of floorplan blocks propagates heat faster or slower. Conclusion Estimating power consumption is critical for hardware, software developers, and other computing system users like Internet companies to save energy or to optimize their HW/SW to be more energy efficient. It is also critical because one can use the available resources accordingly. Simulators are only good during design but their estimation also needs to be verified. Simulators in general have high errors due to manufacturing of hardware components. Power meters measure power consumption for the whole system but does not give detailed breakdowns about dissipated power so designers can optimize their application or hardware. This paper analyzed different methods that researchers have discovered in recent years to resolve some of the issues above. References Energy consumption

laptop Battery Life

Low-power electronics Low-power electronics are electronics, such as notebook processors, that have been designed to use less electric power than usual, often at some expense. In the case of notebook processors, this expense is processing power; notebook processors usually consume less power than their desktop counterparts, at the expense of lower processing power. History Watches The earliest attempts to reduce the amount of power required by an electronic device were related to the development of the wristwatch. Electronic watches require electricity as a power source, and some mechanical movements and hybrid electromechanical movements also require electricity. Usually, the electricity is provided by a replaceable battery. The first use of electrical power in watches was as a substitute for the mainspring, to remove the need for winding. The first electrically powered watch, the Hamilton Electric 500, was released in 1957 by the Hamilton Watch Company of Lancaster, Pennsylvania. The first quartz wristwatches were manufactured in 1976, using analog hands to display the time. Watch batteries (strictly speaking cells, as a battery is composed of multiple cells) are specially designed for their purpose. They are very small and provide tiny amounts of power continuously for very long periods (several years or more). In some cases, replacing the battery requires a trip to a watch repair shop or watch dealer. Rechargeable batteries are used in some solar-powered watches. The first digital electronic watch was a Pulsar LED prototype produced in 1970. Digital LED watches were very expensive and out of reach to the common consumer until 1975, when Texas Instruments started to mass-produce LED watches inside a plastic case. Most watches with LED displays required that the user press a button to see the time displayed for a few seconds because LEDs used so much power that they could not be kept operating continuously. Watches with LED displays were popular for a few years, but soon the LED displays were superseded by liquid crystal displays (LCDs), which used less battery power and were much more convenient in use, with the display always visible and no need to push a button before seeing the time. Only in darkness, you had to press a button to light the display with a tiny light bulb, later illuminating LEDs. Most electronic watches today use 32 kHz quartz oscillators. As of 2013, processors specifically designed for wristwatches are the lowest-power processors manufactured today—often 4-bit, 32 kHz processors. Mobile computing When personal computers were first developed, power consumption was not an issue. With the development of portable computers however, the requirement to run a computer off a battery pack necessitated the search for a compromise between computing power and power consumption. Originally most processors ran both the core and I/O circuits at 5 volts, as in the Intel 8088 used by the first Compaq Portable. It was later reduced to 3.5, 3.3, and 2.5 volts to lower power consumption. For example, the Pentium P5 core voltage decreased from 5V in 1993, to 2.5V in 1997. With lower voltage comes lower overall power consumption, making a system less expensive to run on any existing battery technology and able to function for longer. This is crucially important for portable or mobile systems,. The emphasis on battery operation has driven many of the advances in lowering processor voltage because this has a significant effect on battery life. The second major benefit is that with less voltage and therefore less power consumption, there will be less heat produced. Processors that run cooler can be packed into systems more tightly and will last longer. The third major benefit is that a processor running cooler on less power can be made to run faster. Lowering the voltage has been one of the key factors in allowing the clock rate of processors to go higher and higher. Electronics Computing elements The density and speed of integrated-circuit computing elements has increased exponentially for several decades, following a trend described by Moore's Law. While it is generally accepted that this exponential improvement trend will end, it is unclear exactly how dense and fast integrated circuits will get by the time this point is reached. Working devices have been demonstrated which were fabricated with a MOSFET transistor channel length of 6.3 nanometres using conventional semiconductor materials, and devices have been built that use carbon nanotubes as MOSFET gates, giving a channel length of approximately one nanometre. The density and computing power of integrated circuits are limited primarily by power-dissipation concerns. The overall power consumption of a new personal computer has been increasing at about 22% growth per year. This increase in consumption comes even though the energy consumed by a single CMOS logic gate in order to change its state has fallen exponentially in accordance with Moore's law, by virtue of shrinkage. An integrated-circuit chip contains many capacitive loads, formed both intentionally (as with gate-to-channel capacitance) and unintentionally (between conductors which are near each other but not electrically connected). Changing the state of the circuit causes a change in the voltage across these parasitic capacitances, which involves a change in the amount of stored energy. As the capacitive loads are charged and discharged through resistive devices, an amount of energy comparable to that stored in the capacitor is dissipated as heat: The effect of heat dissipation on state change is to limit the amount of computation that may be performed within a given power budget. While device shrinkage can reduce some parasitic capacitances, the number of devices on an integrated circuit chip has increased more than enough to compensate for reduced capacitance in each individual device. Some circuits – dynamic logic, for example – require a minimum clock rate in order to function properly, wasting "dynamic power" even when they do not perform useful computations. Other circuits – most prominently, the RCA 1802, but also several later chips such as the WDC 65C02, the Intel 80C85, the Freescale 68HC11 and some other CMOS chips – use "fully static logic" that has no minimum clock rate, but can "stop the clock" and hold their state indefinitely. When the clock is stopped, such circuits use no dynamic power but they still have a small, static power consumption caused by leakage current. As circuit dimensions shrink, subthreshold leakage current becomes more prominent. This leakage current results in power consumption, even when no switching is taking place (static power consumption). In modern chips, this current generally accounts for half the power consumed by the IC. Reducing power loss Loss from subthreshold leakage can be reduced by raising the threshold voltage and lowering the supply voltage. Both these changes slow down the circuit significantly. To address this issue, some modern low-power circuits use dual supply voltages to improve speed on critical paths of the circuit and lower power consumption on non-critical paths. Some circuits even use different transistors (with different threshold voltages) in different parts of the circuit, in an attempt to further reduce power consumption without significant performance loss. Another method that is used to reduce power consumption is power gating: the use of sleep transistors to disable entire blocks when not in use. Systems that are dormant for long periods of time and "wake up" to perform a periodic activity are often in an isolated location monitoring an activity. These systems are generally battery- or solar-powered and hence, reducing power consumption is a key design issue for these systems. By shutting down a functional but leaky block until it is used, leakage current can be reduced significantly. For some embedded systems that only function for short periods at a time, this can dramatically reduce power consumption. Two other approaches also exist to lower the power overhead of state changes. One is to reduce the operating voltage of the circuit, as in a dual-voltage CPU, or to reduce the voltage change involved in a state change (making a state change only, changing node voltage by a fraction of the supply voltage—low voltage differential signaling, for example). This approach is limited by thermal noise within the circuit. There is a characteristic voltage (proportional to the device temperature and to the Boltzmann constant), which the state switching voltage must exceed in order for the circuit to be resistant to noise. This is typically on the order of 50–100 mV, for devices rated to 100 degrees Celsius external temperature (about 4 kT, where T is the device's internal temperature in Kelvins and k is the Boltzmann constant). The second approach is to attempt to provide charge to the capacitive loads through paths that are not primarily resistive. This is the principle behind adiabatic circuits. The charge is supplied either from a variable-voltage inductive power supply or by other elements in a reversible-logic circuit. In both cases, the charge transfer must be primarily regulated by the non-resistive load. As a practical rule of thumb, this means the change rate of a signal must be slower than that dictated by the RC time constant of the circuit being driven. In other words, the price of reduced power consumption per unit computation is a reduced absolute speed of computation. In practice, although adiabatic circuits have been built, it has been difficult for them to reduce computation power substantially in practical circuits. Finally, there are several techniques for reducing the number of state changes associated with a given computation. For clocked-logic circuits, the clock gating technique is used, to avoid changing the state of functional blocks that are not required for a given operation. As a more extreme alternative, the asynchronous logic approach implements circuits in such a way that a specific externally supplied clock is not required. While both of these techniques are used to different extents in integrated circuit design, the limit of practical applicability for each appears to have been reached. Wireless communication elements There are a variety of techniques for reducing the amount of battery power required for a desired wireless communication goodput. Some wireless mesh networks use "smart" low power broadcasting techniques that reduce the battery power required to transmit. This can be achieved by using power aware protocols and joint power control systems. Costs In 2007, about 10% of the average IT budget was spent on energy, and energy costs for IT were expected to rise to 50% by 2010. The weight and cost of power supply and cooling systems generally depends on the maximum possible power that could be used at any one time. There are two ways to prevent a system from being permanently damaged by excessive heat. Most desktop computers design power and cooling systems around the worst-case CPU power dissipation at the maximum frequency, maximum workload, and worst-case environment. To reduce weight and cost, many laptop computers choose to use a much lighter, lower-cost cooling system designed around a much lower Thermal Design Power, that is somewhat above expected maximum frequency, typical workload, and typical environment. Typically such systems reduce (throttle) the clock rate when the CPU die temperature gets too hot, reducing the power dissipated to a level that the cooling system can handle. Examples Transmeta Acorn RISC Machine (ARM) AMULET microprocessor Microchip nanoWatt XLP PIC microcontrollers Texas Instruments MSP430 microcontrollers Energy Micro/Silicon Labs EFM32 microcontrollers STMicroelectronics STM32 microcontrollers Atmel/Microchip SAM L microcontrollers See also CPU power dissipation Common Power Format Data organization for low power IT energy management Performance per watt Power management Green computing Dynamic frequency scaling Overclocking Underclocking Dynamic voltage scaling Overvolting Undervolting Operand isolation Glitch removal Autonomous peripheral operation References Further reading (455 pages) External links "High-level design synthesis of a low power, VLIW processor for the IS-54 VSELP Speech Encoder" by Russell Henning and Chaitali Chakrabarti (NB. Implies that, in general, if the algorithm to run is known, hardware designed to specifically run that algorithm will use less power than general-purpose hardware running that algorithm at the same speed.) CRISP: A Scalable VLIW Processor for Low Power Multimedia Systems by Francisco Barat 2005 A Loop Accelerator for Low Power Embedded VLIW Processors by Binu Mathew and Al Davis Ultra-Low Power Design by Jack Ganssle K. Roy and S. Prasad, Low-Power CMOS VLSI Circuit Design, John Wiley & Sons, Inc., , 2000, 359 pages. K-S. Yeo and K. Roy, Low-Voltage Low-Power VLSI Subsystems, McGraw-Hill 2004, , 294 pages. Electric power Electronics and the environment

laptop Battery Life

Solar notebook A solar notebook or solar laptop is a laptop computer with batteries that are recharged by a solar panel attached to the notebook. Features Unlike regular laptops, some models of solar notebooks come with a flap-like structure which functions as a solar panel and can be removed if required. This generates the electricity required to charge its batteries. Like many other laptops, they may include features such as Internet access, GPS and satellite phones. Other models feature external solar modules connected to the laptop and solar keyboard chargers, where the keyboard looks like a solar sheet with the outline of a keyboard imprinted on it. Samsung has integrated the solar panel in the cover (back side of the display) References Applications of photovoltaics Laptops

laptop Battery Life

Research in lithium-ion batteries Research in lithium-ion batteries has produced many proposed refinements of lithium-ion batteries. Areas of research interest have focused on improving energy density, safety, rate capability, cycle durability, flexibility, and cost. Artificial intelligence (AI) and machine learning (ML) is becoming popular in many fields including using it for lithium-ion battery research. These methods have been used in all aspects of battery research including materials, manufacturing, characterization, and prognosis/diagnosis of batteries. Anode Lithium-ion battery anodes are most commonly made of graphite. Graphite anodes are limited to a theoretical capacity of 372 mAh/g for their fully lithiated state. At this time, significant other types of lithium-ion battery anode materials have been proposed and evaluated as alternatives to graphite, especially in cases where niche applications require novel approaches. Intercalation oxides Several types of metal oxides and sulfides can reversibly intercalate lithium cations at voltages between 1 and 2 V against lithium metal with little difference between the charge and discharge steps. Specifically the mechanism of insertion involves lithium cations filling crystallographic vacancies in the host lattice with minimal changes to the bonding within the host lattice. This differentiates intercalation anodes from conversion anodes that store lithium by complete disruption and formation of alternate phases, usually as lithia. Conversion systems typically disproportionate to lithia and a metal (or lower metal oxide) at low voltages, < 1 V vs Li, and reform the metal oxide at voltage > 2 V, for example, CoO + 2Li -> Co+Li2O. Titanium dioxide In 1984, researchers at Bell Labs reported the synthesis and evaluation of a series of lithiated titanates. Of specific interest were the anatase form of titanium dioxide and the lithium spinel LiTi2O4 Anatase has been observed to have a maximum capacity of 150 mAh/g (0.5Li/Ti) with the capacity limited by the availability of crystallographic vacancies in the framework. The TiO2 polytype brookite has also been evaluated and found to be electrochemically active when produced as nanoparticles with a capacity approximately half that of anatase (0.25Li/Ti). In 2014, researchers at Nanyang Technological University used a materials derived from a titanium dioxide gel derived from naturally spherical titanium dioxide particles into nanotubes In addition, a non-naturally occurring electrochemically active titanate referred to as TiO2(B) can be made by ion-exchange followed by dehydration of the potassium titanate K2Ti4O9. This layered oxide can be produced in multiple forms including nanowires, nanotubes, or oblong particles with an observed capacity of 210 mAh/g in the voltage window 1.5–2.0 V (vs Li). Niobates In 2011, Lu et al., reported reversible electrochemical activity in the porous niobate KNb5O13. This material inserted approximately 3.5Li per formula unit (about 125 mAh/g) at a voltage near 1.3 V (vs Li). This lower voltage (compared to titantes) is useful in systems where higher energy density is desirable without significant SEI formation as it operates above the typical electrolyte breakdown voltage. A high rate titanium niobate (TiNb2O7) was reported in 2011 by Han, Huang, and John B. Goodenough with an average voltage near 1.3 V (vs Li). Transition-metal oxides In 2000, researchers from the Université de Picardie Jules Verne examined the use of nano-sized transition-metal oxides as conversion anode materials. The metals used were cobalt, nickel, copper, and iron, which proved to have capacities of 700 mA h/g and maintain full capacity for 100 cycles. The materials operate by reduction of the metal cation to either metal nanoparticles or to a lower oxidation state oxide. These promising results show that transition-metal oxides may be useful in ensuring the integrity of the lithium-ion battery over many discharge-recharge cycles. Lithium Lithium anodes were used for the first lithium-ion batteries in the 1960s, based on the cell chemistry, but were eventually replaced due to dendrite formation which caused internal short-circuits and was a fire hazard. Effort continued in areas that required lithium, including charged cathodes such as manganese dioxide, vanadium pentoxide, or molybdenum oxide and some polymer electrolyte based cell designs. The interest in lithium metal anodes was re-established with the increased interest in high capacity lithium–air battery and lithium–sulfur battery systems. Research to inhibit dendrite formation has been an active area. Doron Aurbach and co-workers at Bar-Ilan University have extensively studied the role of solvent and salt in the formation of films on the lithium surface. Notable observations were the addition of LiNO3, dioxolane, and hexafluoroarsenate salts. They appeared to create films that inhibit dendrite formation while incorporating reduced Li3As as a lithium-ion conductive component. In 2021, researchers announced the use of thin (20 micron) lithium metal strips. They were able to achieve energy density of 350 Wh/kg over 600 charge/discharge cycles. Non-graphitic carbon Various forms of carbon are used in lithium-ion battery cell configurations. Besides graphite poorly or non-electrochemically active types of carbon are used in cells such as CNTs, carbon black, graphene, graphene oxides, or MWCNTs. Recent work includes efforts in 2014 by researchers at Northwestern University who found that metallic single-walled carbon nanotubes (SWCNTs) accommodate lithium much more efficiently than their semiconducting counterparts. If made denser, semiconducting SWCNT films take up lithium at levels comparable to metallic SWCNTs. Hydrogen-treatment of graphene nanofoam electrodes in LIBs was shown to improve their capacity and transport properties. Chemical synthesis methods used in standard anode manufacture leave significant amounts of atomic hydrogen. Experiments and multiscale calculations revealed that low-temperature hydrogen treatment of defect-rich graphene can improve rate capacity. The hydrogen interacts with the graphene defects to open gaps to facilitate lithium penetration, improving transport. Additional reversible capacity is provided by enhanced lithium binding near edges, where hydrogen is most likely to bind. Rate capacities increased by 17–43% at 200 mA/g. In 2015, researchers in China used porous graphene as the material for a lithium ion battery anode in order to increase the specific capacity and binding energy between lithium atoms at the anode. The properties of the battery can be tuned by applying strain. The binding energy increases as biaxial strain is applied. Silicon Silicon is an earth abundant element, and is fairly inexpensive to refine to high purity. When alloyed with lithium it has a theoretical capacity of ~3,600 milliampere hours per gram (mAh/g), which is nearly 10 times the energy density of graphite electrodes, which exhibit a maximum capacity of 372 mAh/g for their fully lithiated state of LiC6. One of silicon's inherent traits, unlike carbon, is the expansion of the lattice structure by as much as 400% upon full lithiation (charging). For bulk electrodes, this causes great structural stress gradients within the expanding material, inevitably leading to fractures and mechanical failure, which significantly limits the lifetime of the silicon anodes. In 2011, a group of researchers assembled data tables that summarized the morphology, composition, and method of preparation of those nanoscale and nanostructured silicon anodes, along with their electrochemical performance. Porous silicon nanoparticles are more reactive than bulk silicon materials and tend to have a higher weight percentage of silica as a result of the smaller size. Porous materials allow for internal volume expansion to help control overall materials expansion. Methods include a silicon anode with an energy density above 1,100 mAh/g and a durability of 600 cycles that used porous silicon particles using ball-milling and stain-etching. In 2013, researchers developed a battery made from porous silicon nanoparticles. Below are various structural morphologies attempted to overcome issue with silicon's intrinsic properties. Silicon encapsulation As a method to control the ability of fully lithiated silicon to expand and become electronically isolated, a method for caging 3 nm-diameter silicon particles in a shell of graphene was reported in 2016. The particles were first coated with nickel. Graphene layers then coated the metal. Acid dissolved the nickel, leaving enough of a void within the cage for the silicon to expand. The particles broke into smaller pieces, but remained functional within the cages. In 2014, researchers encapsulated silicon nanoparticles inside carbon shells, and then encapsulated clusters of the shells with more carbon. The shells provide enough room inside to allow the nanoparticles to swell and shrink without damaging the shells, improving durability. Silicon nanowire In 2021 Paul V.Braun's group at University of Illinois at Urbana-Champaign developed a large-scale and low-cost approach for synthesizing Si/Cu nanowires. Firstly, Si/Cu/Zn ternary microspheres are prepared by a pulsed electrical discharging method in a scalable manner, and then Zn and partial Si in the microspheres was partially removed by chemical etching to form Si/Cu nanowires. This technology utilizes relatively cheap materials and flexible processing methods, costing approximately $0.3 g−1, which is promising to boost the yield of Si alloy NWs with low cost. Porous-silicon inorganic-electrode design In 2012, Vaughey, et al., reported a new all-inorganic electrode structure based on electrochemically active silicon particles bound to a copper substrate by a Cu3Si intermetallic. Copper nanoparticles were deposited on silicon particles articles, dried, and laminated onto a copper foil. After annealing, the copper nanoparticles annealed to each other and to the copper current collector to produce a porous electrode with a copper binder once the initial polymeric binder burned out. The design had performance similar to conventional electrode polymer binders with exceptional rate capability owing to the metallic nature of the structure and current pathways. Silicon nanofiber In 2015, a prototype electrode was demonstrated that consists of sponge-like silicon nanofibers increases Coulombic efficiency and avoids the physical damage from silicon's expansion/contractions. The nanofibers were created by applying a high voltage between a rotating drum and a nozzle emitting a solution of tetraethyl orthosilicate (TEOS). The material was then exposed to magnesium vapors. The nanofibers contain 10 nm diameter nanopores on their surface. Along with additional gaps in the fiber network, these allow for silicon to expand without damaging the cell. Three other factors reduce expansion: a 1 nm shell of silicon dioxide; a second carbon coating that creates a buffer layer; and the 8-25 nm fiber size, which is below the size at which silicon tends to fracture. Conventional lithium-ion cells use binders to hold together the active material and keep it in contact with the current collectors. These inactive materials make the battery bigger and heavier. Experimental binderless batteries do not scale because their active materials can be produced only in small quantities. The prototype has no need for current collectors, polymer binders or conductive powder additives. Silicon comprises over 80 percent of the electrode by weight. The electrode delivered 802 mAh/g after more than 600 cycles, with a Coulombic efficiency of 99.9 percent. Tin Lithium tin Zintl phases, discovered by Eduard Zintl, have been studied as anode materials in lithium-ion energy storage systems for several decades. First reported in 1981 by Robert Huggins, the system has a multiphase discharge curve and stores approximately 1000 mAh/g (Li22Sn5). Tin and its compounds have been extensively studied but, similar to silicon or germanium anode systems, issues associated with volume expansion (associated with gradual filling of p-orbitals and essential cation insertion), unstable SEI formation, and electronic isolation have been studied in an attempt to commercialize these materials. In 2013, work on morphological variation by researchers at Washington State University used standard electroplating processes to create nanoscale tin needles that show 33% lower volume expansion during charging. In 2015, the research team at University of Illinois at Urbana-Champaign create a 3D mechanically stable nickel–tin nanocomposite scaffold as a Li-ion battery anode. This scaffold can accommodate the volume change of a high-specific-capacity during operation. And nickel–tin anode is supported by an electrochemically inactive conductive scaffold with an engineered free volume and controlled characteristic dimensions, so the electrode with significantly improved cyclability. Intermetallic insertion materials As for oxide intercalation (or insertion) anode materials, similar classes of materials where the lithium cation is inserted into crystallographic vacancies within a metal host lattice have been discovered and studied since 1997. In general because of the metallic lattice, these types of materials, for example Cu6Sn5, Mn2Sb, lower voltages and higher capacities have been found when compared to their oxide counterparts. Cu6Sn5 Cu6Sn5 is an intermetallic alloy with a defect NiAs type structure. In NiAs type nomenclature it would have the stoichiometry Cu0.2CuSn, with 0.2 Cu atoms occupying a usually unoccupied crystallographic position in the lattice. These copper atoms are displaced to the grain boundaries when charged to form Li2CuSn. With retention of most of the metal-metal bonding down to 0.5 V, Cu6Sn5 has become an attractive potential anode material due to its high theoretical specific capacity, resistance against Li metal plating especially when compared to carbon-based anodes, and ambient stability. In this and related NiAs-type materials, lithium intercalation occurs through an insertion process to fill the two crystallographic vacancies in the lattice, at the same time as the 0.2 extra coppers are displaced to the grain boundaries. Efforts to charge compensate the main group metal lattice to remove the excess copper have had limited success. Although significant retention of structure is noted down to the ternary lithium compound Li2CuSn, over discharging the material results in disproportionation with formation of Li22Sn5 and elemental copper. This complete lithiation is accompanied by volume expansion of approximately 250%. Current research focuses on investigating alloying and low dimensional geometries to mitigate mechanical stress during lithiation. Alloying tin with elements that do not react with lithium, such as copper, has been shown to reduce stress. As for low dimensional applications, thin films have been produced with discharge capacities of 1127 mAhg−1 with excess capacity assigned to lithium ion storage at grain boundaries and associated with defect sites. Other approaches include making nanocomposites with Cu6Sn5 at its core with a nonreactive outer shell, SnO2-c hybrids have been shown to be effective, to accommodate volume changes and overall stability over cycles. Copper antimonide The layered intermetallic materials derived from the Cu2Sb-type structure are attractive anode materials due to the open gallery space available and structural similarities to the discharge Li2CuSb product. First reported in 2001. In 2011, researchers reported a method to create porous three dimensional electrodes materials based on electrodeposited antimony onto copper foams followed by a low temperature annealing step. It was noted to increase the rate capacity by lowering the lithium diffusion distances while increasing the surface area of the current collector. In 2015, researchers announced a solid-state 3-D battery anode using the electroplated copper antimonide (copper foam). The anode is then layered with a solid polymer electrolyte that provides a physical barrier across which ions (but not electrons) can travel. The cathode is an inky slurry. The volumetric energy density was up to twice as much energy conventional batteries. The solid electrolyte prevents dendrite formation. Three-dimensional nanostructure Nanoengineered porous electrodes have the advantage of short diffusion distances, room for expansion and contraction, and high activity. In 2006 an example of a three dimensional engineered ceramic oxide based on lithium titante was reported that had dramatic rate enhancement over the non-porous analogue. Later work by Vaughey et al., highlighted the utility of electrodeposition of electroactive metals on copper foams to create thin film intermetallic anodes. These porous anodes have high power in addition to higher stability as the porous open nature of the electrode allows for space to absorb some of the volume expansion. In 2011, researchers at University of Illinois at Urbana-Champaign discovered that wrapping a thin film into a three-dimensional nanostructure can decrease charge time by a factor of 10 to 100. The technology is also capable of delivering a higher voltage output. In 2013, the team improved the microbattery design, delivering 30 times the energy density 1,000x faster charging. The technology also delivers better power density than supercapacitors. The device achieved a power density of 7.4 W/cm2/mm. In 2019, the team develop a high areal and volumetric capacity 3D-structured Sn/C anode by using a two steps electroplating process, which exhibits a high volumetric/areal capacity of ∼879 mA h/cm3/6.59 mA h/cm2 after 100 cycles at 0.5 C and 750 mA h/cm3 and 5.5 mA h/cm2 (delithiation) at 10 C with a 20%v/v Sn loading in a half-cell configuration. Semi-solid In 2016, researchers announced an anode composed of a slurry of Lithium-iron phosphate and graphite with a liquid electrolyte. They claimed that the technique increased safety (the anode could be deformed without damage) and energy density. A flow battery without carbon, called Solid Dispersion Redox Flow Battery, was reported, proposing increased energy density and high operating efficiencies. A review of different semi-solid battery systems can be found here. Cathode Several varieties of cathode exist, but typically they can easily divided into two categories, namely charged and discharged. Charged cathodes are materials with pre-existing crystallographic vacancies. These materials, for instance spinels, vanadium pentoxide, molybdenum oxide or LiV3O8, typically are tested in cell configurations with a lithium metal anode as they need a source of lithium to function. While not as common in secondary cell designs, this class is commonly seen in primary batteries that do not require recharging, such as implantable medical device batteries. The second variety are discharged cathodes where the cathode typically in a discharged state (cation in a stable reduced oxidation state), has electrochemically active lithium, and when charged, crystallographic vacancies are created. Due to their increased manufacturing safety and without the need for a lithium source at the anode, this class is more commonly studied. Examples include lithium cobalt oxide, lithium nickel manganese cobalt oxide NMC, or lithium iron phosphate olivine which can be combined with most anodes such as graphite, lithium titanate spinel, titanium oxide, silicon, or intermetallic insertion materials to create a working electrochemical cell. Vanadium oxides Vanadium oxides have been a common class of cathodes to study due to their high capacity, ease of synthesis, and electrochemical window that matches well with common polymer electrolytes. Vanadium oxides cathodes, typically classed as charged cathodes, are found in many different structure types. These materials have been extensively studied by Stanley Whittingham among others. In 2007, Subaru introduced a battery with double the energy density while only taking 15 minutes for an 80% charge. They used a nanostructured vanadium oxide, which is able to load two to three times more lithium ions onto the cathode than the layered lithium cobalt oxide. In 2013 researchers announced a synthesis of hierarchical vanadium oxide nanoflowers (V10O24·nH2O) synthesized by an oxidation reaction of vanadium foil in a NaCl aqueous solution. Electrochemical tests demonstrate deliver high reversible specific capacities with 100% coulombic efficiency, especially at high C rates (e.g., 140 mAh g−1 at 10 C). In 2014, researchers announced the use of vanadate-borate glasses (V2O5 – LiBO2 glass with reduced graphite oxide) as a cathode material. The cathode achieved around 1000 Wh/kg with high specific capacities in the range of ~ 300 mAh/g for the first 100 cycles. Disordered materials In 2014, researchers at Massachusetts Institute of Technology found that creating high lithium content lithium-ion batteries materials with cation disorder among the electroactive metals could achieve 660 watt-hours per kilogram at 2.5 volts. The materials of the stoichiometry Li2MO3-LiMO2 are similar to the lithium rich lithium nickel manganese cobalt oxide (NMC) materials but without the cation ordering. The extra lithium creates better diffusion pathways and eliminates high energy transition points in the structure that inhibit lithium diffusion. Glasses In 2015 researchers blended powdered vanadium pentoxide with borate compounds at 900 C and quickly cooled the melt to form glass. The resulting paper-thin sheets were then crushed into a powder to increase their surface area. The powder was coated with reduced graphite oxide (RGO) to increase conductivity while protecting the electrode. The coated powder was used for the battery cathodes. Trials indicated that capacity was quite stable at high discharge rates and remained consistently over 100 charge/discharge cycles. Energy density reached around 1,000 watt-hours per kilogram and a discharge capacity that exceeded 300 mAh/g. Sulfur Used as the cathode for a lithium–sulfur battery this system has high capacity on the formation of Li2S. In 2014, researchers at USC Viterbi School of Engineering used a graphite oxide coated sulfur cathode to create a battery with 800 mAh/g for 1,000 cycles of charge/discharge, over 5 times the energy density of commercial cathodes. Sulfur is abundant, low cost and has low toxicity. Sulfur has been a promising cathode candidate owing to its high theoretical energy density, over 10 times that of metal oxide or phosphate cathodes. However, sulfur's low cycle durability has prevented its commercialization. Graphene oxide coating over sulfur is claimed to solve the cycle durability problem. Graphene oxide high surface area, chemical stability, mechanical strength and flexibility. Seawater In 2012, researchers at Polyplus Corporation created a battery with an energy density more than triple that of traditional lithium-ion batteries using the halides or organic materials in seawater as the active cathode. Its energy density is 1,300 W·h/kg, which is a lot more than the traditional 400 W·h/kg. It has a solid lithium positive electrode and a solid electrolyte. It could be used in underwater applications. Lithium-based cathodes Lithium nickel manganese cobalt oxide In 1998, a team from Argonne National Laboratory reported on the discovery of lithium rich NMC cathodes., These high capacity high voltage materials consist of nanodomains of the two structurally similar but different materials. On first charge, noted by its long plateau around 4.5V (vs Li), the activation step creates a structure that gradually equilibrates to a more stable materials by cation re-positioning from high energy points to lower energy points in the lattice. The intellectual property surrounding these materials has been licensed to several manufacturers including BASF, General Motors for the Chevy Volt and Chevy Bolt, and Toda. The mechanism for the high capacity and the gradual voltage fade has been extensively examined. It is generally believed the high voltage activation step induces various cation defects that on cycling equilibrate through the lithium-layer sites to a lower energy state that exhibits a lower cell voltage but with a similar capacity,. Lithium–iron phosphate LiFePO4 is a 3.6 V lithium-ion battery cathode initially reported by John Goodenough and is structurally related to the mineral olivine and consists of a three dimensional lattice of an [FePO4] framework surrounding a lithium cation. The lithium cation sits in a one dimensional channel along the [010] axis of the crystal structure. This alignment yields anisotropic ionic conductivity that has implications for its usage as a battery cathode and makes morphological control an important variable in its electrochemical cell rate performance. Although the iron analogue is the most commercial owing to its stability, the same composition exists for nickel, manganese, and cobalt although the observed high cell charging voltages and synthetic challenges for these materials make them viable but more difficult to commercialize. While the material has good ionic conductivity it possesses poor intrinsic electronic conductivity. This combination makes nanophase compositions and composites or coatings (to increase electronic conductivity of the whole matrix) with materials such as carbon advantageous. Alternatives to nanoparticles include mesoscale structure such as nanoball batteries of the olivine LiFePO4 that can have rate capabilities two orders of magnitude higher than randomly ordered materials. The rapid charging is related to the nanoballs high surface area where electrons are transmitted to the surface of the cathode at a higher rate. In 2012, researchers at A123 Systems developed a battery that operates in extreme temperatures without the need for thermal management material. It went through 2,000 full charge-discharge cycles at 45 °C while maintaining over 90% energy density. It does this using a nanophosphate positive electrode. Lithium manganese silicon oxide A "lithium orthosilicate-related" cathode compound, , was able to support a charging capacity of 335 mAh/g. Li2MnSiO4@C porous nanoboxes were synthesized via a wet-chemistry solid-state reaction method. The material displayed a hollow nanostructure with a crystalline porous shell composed of phase-pure Li2MnSiO4 nanocrystals. Powder X-ray diffraction patterns and transmission electron microscopy images revealed that the high phase purity and porous nanobox architecture were achieved via monodispersed MnCO3@SiO2 core–shell nanocubes with controlled shell thickness. Air In 2009, researchers at the University of Dayton Research Institute announced a solid-state battery with higher energy density that uses air as its cathode. When fully developed, the energy density could exceed 1,000 Wh/kg. In 2014, researchers at the School of Engineering at the University of Tokyo and Nippon Shokubai discovered that adding cobalt to the lithium oxide crystal structure gave it seven times the energy density. In 2017, researchers at University of Virginia reported a scalable method to produce sub-micrometer scale lithium cobalt oxide. Iron fluoride Iron fluoride, a potential intercalation-conversion cathode, presents a high theoretical energy density of 1922 Wh kg−1. This material displays poor electrochemical reversibility. When doped with cobalt and oxygen, reversibility improves to over 1000 cycles and capacity reaches 420 mAh g−1. Doping changes the reaction from less-reversible intercalation-conversion to a highly reversible intercalation-extrusion. Electrolyte Currently, electrolytes are typically made of lithium salts in a liquid organic solvent. Common solvents are organic carbonates (cyclic, straight chain), sulfones, imides, polymers (polyethylene oxide) and fluorinated derivatives. Common salts include LiPF6, LiBF4, LiTFSI, and LiFSI. Research centers on increased safety via reduced flammability and reducing shorts via preventing dendrites. Perfluoropolyether In 2014, researchers at University of North Carolina found a way to replace the electrolyte's flammable organic solvent with nonflammable perfluoropolyether (PFPE). PFPE is usually used as an industrial lubricant, e.g., to prevent marine life from sticking to the ship bottoms. The material exhibited unprecedented high transference numbers and low electrochemical polarization, indicative of a higher cycle durability. Solid-state While no solid-state batteries have reached the market, multiple groups are researching this alternative. The notion is that solid-state designs are safer because they prevent dendrites from causing short circuits. They also have the potential to substantially increase energy density because their solid nature prevents dendrite formation and allows the use of pure metallic lithium anodes. They may have other benefits such as lower temperature operation. In 2015, researchers announced an electrolyte using superionic lithium-ion conductors, which are compounds of lithium, germanium, phosphorus and sulfur. Thiophosphate In 2015, researchers worked with a lithium carbon fluoride battery. They incorporated a solid lithium thiophosphate electrolyte wherein the electrolyte and the cathode worked in cooperation, resulting in capacity 26 percent. Under discharge, the electrolyte generates a lithium fluoride salt that further catalyzes the electrochemical activity, converting an inactive component to an active one. More significantly, the technique was expected to substantially increase battery life. Glassy electrolytes In March 2017, researchers announced a solid-state battery with a glassy ferroelectric electrolyte of lithium, oxygen, and chlorine ions doped with barium, a lithium metal anode, and a composite cathode in contact with a copper substrate. A spring behind the copper cathode substrate holds the layers together as the electrodes change thickness. The cathode comprises particles of sulfur "redox center", carbon, and electrolyte. During discharge, the lithium ions plate the cathode with lithium metal and the sulfur is not reduced unless irreversible deep discharge occurs. The thickened cathode is a compact way to store the used lithium. During recharge, this lithium moves back into the glassy electrolyte and eventually plates the anode, which thickens. No dendrites form. The cell has 3 times the energy density of conventional lithium-ion batteries. An extended life of more than 1,200 cycles was demonstrated. The design also allows the substitution of sodium for lithium minimizing lithium environmental issues. Salts Superhalogen Conventional electrolytes generally contain halogens, which are toxic. In 2015 researchers claimed that these materials could be replaced with non-toxic superhalogens with no compromise in performance. In superhalogens the vertical electron detachment energies of the moieties that make up the negative ions are larger than those of any halogen atom. The researchers also found that the procedure outlined for Li-ion batteries is equally valid for other metal-ion batteries, such as sodium-ion or magnesium-ion batteries. Water-in-salt In 2015, researchers at the University of Maryland and the Army Research Laboratory showed significantly increased stable potential windows for aqueous electrolytes with very high salt concentration. By increasing the molality of Bis(trifluoromethane)sulfonimide lithium salt to 21 m, the potential window could be increased from 1.23 to 3 V due to the formation of SEI on the anode electrode, which has previously only been accomplished with non-aqueous electrolytes. Using aqueous rather than organic electrolyte could significantly improve the safety of Li-ion batteries. Dual anionic liquid An experimental lithium metal battery with a /NCM88 cathode material with a dual-anion ionic liquid electrolyte (ILE) was demonstrated in 2021. This electrolyte enables initial specific capacity of 214 mAh g−1 and 88% capacity retention over 1,000 cycles with an average Coulombic efficiency of 99.94%. The cells achieved a specific energy above 560 Wh kg−1 at >4 volts. Capacity after 1k cycles was 88%. Importantly, the cathode retained its structural integrity throughout the charging cycles. Design and management Charging In 2014, researchers at MIT, Sandia National Laboratories, Samsung Advanced Institute of Technology America and Lawrence Berkeley National Laboratory discovered that uniform charging could be used with increased charge speed to speed up battery charging. This discovery could also increase cycle durability to ten years. Traditionally slower charging prevented overheating, which shortens cycle durability. The researchers used a particle accelerator to learn that in conventional devices each increment of charge is absorbed by a single or a small number of particles until they are charged, then moves on. By distributing charge/discharge circuitry throughout the electrode, heating and degradation could be reduced while allowing much greater power density. In 2014, researchers at Qnovo developed software for a smartphone and a computer chip capable of speeding up re-charge time by a factor of 3-6, while also increasing cycle durability. The technology is able to understand how the battery needs to be charged most effectively, while avoiding the formation of dendrites. In 2019, Chao-Yang Wang from Penn State University found that it is possible to recharge the (conventional) lithium-ion batteries of EV's in under 10 minutes. He did so by heating the battery to 60 °C, recharging it and then cooling if quickly afterwards. This causes only very little damage to the batteries. Professor Wang used a thin nickel foil with one end attached to the negative terminal and the other end extending to outside the cell in order to create a third terminal. A temperature sensor attached to a switch completes the circuit. Management Durability In 2014, independent researchers from Canada announced a battery management system that increased cycles four-fold, that with specific energy of 110–175 Wh/kg using a battery pack architecture and controlling algorithm that allows it to fully utilize the active materials in battery cells. The process maintains lithium-ion diffusion at optimal levels and eliminates concentration polarization, thus allowing the ions to be more uniformly attached/detached to the cathode. The SEI layer remains stable, preventing energy density losses. Thermal In 2016, researchers announced a reversible shutdown system for preventing thermal runaway. The system employed a thermoresponsive polymer switching material. This material consists of electrochemically stable, graphene-coated, spiky nickel nanoparticles in a polymer matrix with a high thermal expansion coefficient. Film electrical conductivity at ambient temperature was up to 50 S cm−1. Conductivity decreases within one second by 107-108 at the transition temperature and spontaneously recovers at room temperature. The system offers 103–104x greater sensitivity than previous devices. Flexibility In 2014, multiple research teams and vendors demonstrated flexible battery technologies for potential use in textiles and other applications. One technique made li-ion batteries flexible, bendable, twistable and crunchable using the Miura fold. This discovery uses conventional materials and could be commercialized for foldable smartphones and other applications. Another approached used carbon nanotube fiber yarns. The 1 mm diameter fibers were claimed to be lightweight enough to create weavable and wearable textile batteries. The yarn was capable of storing nearly 71 mAh/g. Lithium manganate (LMO) particles were deposited on a carbon nanotube (CNT) sheet to create a CNT-LMO composite yarn for the cathode. The anode composite yarns sandwiched a CNT sheet between two silicon-coated CNT sheets. When separately rolled up and then wound together separated by a gel electrolyte the two fibers form a battery. They can also be wound onto a polymer fiber, for adding to an existing textile. When silicon fibers charge and discharge, the silicon expands in volume up to 300 percent, damaging the fiber. The CNT layer between the silicon-coated sheet buffered the silicon's volume change and held it in place. A third approach produced rechargeable batteries that can be printed cheaply on commonly used industrial screen printers. The batteries used a zinc charge carrier with a solid polymer electrolyte that prevents dendrite formation and provides greater stability. The device survived 1,000 bending cycles without damage. A fourth group created a device that is one hundredth of an inch thick and doubles as a supercapacitor. The technique involved etching a 900 nanometer-thick layer of Nickel(II) fluoride with regularly spaced five nanometer holes to increase capacity. The device used an electrolyte made of potassium hydroxide in polyvinyl alcohol. The device can also be used as a supercapacitor. Rapid charging allows supercapacitor-like rapid discharge, while charging with a lower current rate provides slower discharge. It retained 76 percent of its original capacity after 10,000 charge-discharge cycles and 1,000 bending cycles. Energy density was measured at 384 Wh/kg, and power density at 112 kW/kg. Volume expansion Current research has been primarily focused on finding new materials and characterising them by means of specific capacity (mAh/g), which provides a good metric to compare and contrast all electrode materials. Recently, some of the more promising materials are showing some large volume expansions which need to be considered when engineering devices. Lesser known to this realm of data is the volumetric capacity (mAh/cm3) of various materials to their design. Nanotechnology Researchers have taken various approaches to improving performance and other characteristics by using nanostructured materials. One strategy is to increase electrode surface area. Another strategy is to reduce the distance between electrodes to reduce transport distances. Yet another strategy is to allow the use of materials that exhibit unacceptable flaws when used in bulk forms, such as silicon. Finally, adjusting the geometries of the electrodes, e.g., by interdigitating anode and cathode units variously as rows of anodes and cathodes, alternating anodes and cathodes, hexagonally packed 1:2 anodes:cathodes and alternating anodic and cathodic triangular poles. One electrode can be nested within another. Carbon nanotubes and nanowires have been examined for various purposes, as have aerogels and other novel bulk materials. Finally, various nanocoatings have been examined, to increase electrode stability and performance. Nanosensors is now being integrated in to each cell of the battery. This will help to monitor the state of charge in real time which will be helpful not only for security reason but also be useful to maximize the use of the battery. Economy In 2016, researchers from CMU found that prismatic cells are more likely to benefit from production scaling than cylindrical cells. Repurposing and reuse The elimination of power batteries made by lithium-ion batteries has largely increased, causing environmental protection threats and waste of resources. About 100-120 GWh of electric vehicle batteries will be retired by 2030. Hence, recycling and reuse of such retired power batteries have been suggested. Some retired power batteries still have ~80% of their initial capacity. So they can be repurposed and reused as second-life applications, for instance, to serve the batteries in the energy storage systems. Governments in different countries have acknowledged this emergent problem and prepared to launch their policies to deal with repurposed batteries, such as coding principles, traceability management system, manufacturing factory guidelines, dismantling process guidelines, residual energy measurement, tax credits, rebates, and financial support. Standards for second-life applications of retired electric vehicle batteries are still emerging technology. One of the few standards, UL 1974, was published by Underwriters Laboratories (UL). The document gives a general procedure of the safety operations and performance tests on retired power battery cells, packs, and modules, but could not detail the steps and specifics. For applications in the real world, the design, form factor, and materials of the existing battery cells, packs, and modules often vary greatly from one another. It is difficult to develop a unified technical procedure. Furthermore, information on the detailed technical procedures applied is usually not available in the open literature, except for Schneider et al. who demonstrated the procedure to refurbish small cylindrical NiMH batteries used in mobile phones, Zhao who published the successful experiences of some grid-oriented applications of electric vehicle lithium-ion batteries in China, and Chung who reported the procedure described in UL 1974 on a LiFePO4 repurposing battery. See also Lithium–sulfur battery Trickle charging References Lithium-ion batteries

laptop Battery Life

Memory effect Memory effect, also known as battery effect, lazy battery effect, or battery memory, is an effect observed in nickel-cadmium and nickel–metal hydride rechargeable batteries that causes them to hold less charge. It describes the situation in which nickel-cadmium batteries gradually lose their maximum energy capacity if they are repeatedly recharged after being only partially discharged. The battery appears to "remember" the smaller capacity. True memory effect The term "memory" came from an aerospace nickel-cadmium application in which the cells were repeatedly discharged to 25% of available capacity (plus or minus 1%) by exacting computer control, then recharged to 100% capacity without overcharge. This long-term, repetitive cycle régime, with no provision for overcharge, resulted in a loss of capacity beyond the 25% discharge point. True memory cannot exist if any one (or more) of the following conditions holds: batteries achieve full overcharge. discharge is not exactly the same each cycle, within plus or minus 3% discharge is to less than 1.0 volt per cell True memory-effect is specific to sintered-plate nickel-cadmium cells, and is exceedingly difficult to reproduce, especially in lower ampere-hour cells. In one particular test program designed to induce the effect, none was found after more than 700 precisely-controlled charge/discharge cycles. In the program, spirally-wound one-ampere-hour cells were used. In a follow-up program, 20-ampere-hour aerospace-type cells were used on a similar test régime; memory effects were observed after a few hundred cycles. Other problems perceived as memory effect Phenomena which are not true memory effects may also occur in battery types other than sintered-plate nickel-cadmium cells. In particular, lithium-based cells, not normally subject to the memory effect, may change their voltage levels so that a virtual decrease of capacity may be perceived by the battery control system. Temporary effects Voltage depression due to long-term over-charging A common process often ascribed to memory effect is voltage depression. In this case, the output voltage of the battery drops more quickly than normal as it is used, even though the total capacity remains almost the same. In modern electronic equipment that monitors the voltage to indicate battery charge, the battery appears to be draining very quickly. To the user, it appears the battery is not holding its full charge, which seems similar to memory effect. This is a common problem with high-load devices such as digital cameras and cell phones. Voltage depression is caused by repeated over-charging of a battery, which causes the formation of small crystals of electrolyte on the plates. These can clog the plates, increasing resistance and lowering the voltage of some individual cells in the battery. This causes the battery as a whole to seem to discharge rapidly as those individual cells discharge quickly and the voltage of the battery as a whole suddenly falls. This effect is very common, as consumer trickle chargers typically overcharge. Repair The effect can be overcome by subjecting each cell of the battery to one or more deep charge/discharge cycles. This must be done to the individual cells, not a multi-cell battery; in a battery, some cells may discharge before others, resulting in those cells being subjected to a reverse charging current by the remaining cells, potentially leading to irreversible damage. High temperatures High temperatures can also reduce the charged voltage and the charge accepted by the cells. Other causes Operation below 32 °F (0 °C) High discharge rates (above 5C) in a battery not specifically designed for such use Inadequate charging time Defective charger Permanent loss of capacity Deep discharge Some rechargeable batteries can be damaged by repeated deep discharge. Batteries are composed of multiple similar, but not identical, cells. Each cell has its own charge capacity. As the battery as a whole is being deeply discharged, the cell with the smallest capacity may reach zero charge and will "reverse charge" as the other cells continue to force current through it. The resulting loss of capacity is often ascribed to the memory effect. Battery users may attempt to avoid the memory effect proper by fully discharging their battery packs. This practice is likely to cause more damage as one of the cells will be deep discharged. The damage is focused on the weakest cell, so that each additional full discharge will cause more and more damage to that cell. Age and use—normal end-of-life All rechargeable batteries have a finite lifespan and will slowly lose storage capacity as they age due to secondary chemical reactions within the battery whether it is used or not. Some cells may fail sooner than others, but the effect is to reduce the voltage of the battery. Lithium-based batteries have one of the longest idle lives of any construction. Unfortunately the number of operational cycles is still quite low at approximately 400–1200 complete charge/discharge cycles. The lifetime of lithium batteries decreases at higher temperature and states of charge (SoC), whether used or not; maximum life of lithium cells when not in use(storage) is achieved by refrigerating (without freezing) charged to 30%–50% SoC. To prevent overdischarge, battery should be brought back to room temperature and recharged to 50% SoC once every six months or once per year. References Further reading Rechargeable Batteries Applications Handbook from Gates Energy Products, published since 1992 April 10. Battery charging Rechargeable batteries

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PC power management PC power management refers to software-based mechanisms for controlling the power use of personal computer hardware. This is typically through the use of software that puts the hardware into the lowest power demand state available. It is an aspect of Green computing. A typical office PC uses about 90 watts when active (approximately 50 watts for the base unit, and 40 watts for a typical LCD screen); and three to four watts when ‘asleep’. Up to 10% of a modern office’s electricity demand can be due to PCs and monitors. While most PCs allow low power settings, there are frequently situations, especially in a networked environment, where processes running on the computer will prevent the low power settings from taking effect. This can have a dramatic effect on energy use that is invisible to the user. Operational testing has shown that on any given day an average of over 50% of an organisation's computers will fail to go to sleep, and over long periods of time this affects over 90% of machines. This leads to most computers having the option of customising power management systems, and has created a market for third-party power management software to further control a computer’s power use. Windows 'Insomnia' (Sleepless PCs) The Windows power management system is based upon an idle timer. If the computer is idle for longer than the preset timeout then the PC may be configured to sleep or hibernate. The user may configure the timeout using the Control Panel. Windows uses a combination of user activity and CPU activity to determine when the computer is idle. Applications can temporarily inhibit this timer by using the SetThreadExecutionState API. There are legitimate reasons why this may be necessary such as burning a DVD or playing a video. However, in many cases applications can unnecessarily prevent power management from working. This is commonly known as Windows 'Insomnia' and can be a significant barrier to successfully implementing power management. Common causes of 'insomnia' include: Legacy or non-power management aware applications Open file handles on remote computers Faulty mice which can cause pointer drift. This makes the operating system believe that a user is present Scheduled maintenance tasks causing significant CPU activity High network activity Software solutions Operating systems have built-in settings to control power use. Microsoft Windows supports predefined power plans and custom sleep and hibernation settings through a Control Panel Power Options applet. Apple's macOS includes idle and sleep configuration settings through the Energy Saver System Preferences applet. Likewise, Linux distributions include a variety of power management settings and tools. There is a significant market in third-party PC power management software offering features beyond those present in the Windows operating system. Notable vendors include 1E NightWatchman, Data Synergy PowerMAN (Software), Faronics Power Save, Verdiem SURVEYOR. and EnviProt Auto Shutdown Manager Some studies have suggested that power management tools can save on average 200 kg of CO2 emissions per PC per year, and generate $36 per PC per year in energy savings. This makes power management software an attractive option for large companies. See also IT energy management ACPI References Personal computers Sustainable technologies Computers and the environment Power management

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Processor power dissipation Processor power dissipation or processing unit power dissipation is the process in which computer processors consume electrical energy, and dissipate this energy in the form of heat due to the resistance in the electronic circuits. Power management Designing CPUs that perform tasks efficiently without overheating is a major consideration of nearly all CPU manufacturers to date. Historically, early CPUs implemented with vacuum tubes consumed power on the order of many kilowatts. Current CPUs in general-purpose personal computers, such as desktops and laptops, consume power in the order of tens to hundreds of watts. Some other CPU implementations use very little power; for example, the CPUs in mobile phones often use just a few watts of electricity, while some microcontrollers used in embedded systems may consume only a few milliwatts or even as little as a few microwatts. There are a number of engineering reasons for this pattern: For a given CPU core, energy usage will scale up as its clock rate increases. Reducing the clock rate or undervolting usually reduces energy consumption; it is also possible to undervolt the microprocessor while keeping the clock rate the same. New features generally require more transistors, each of which uses power. Turning unused areas off saves energy, such as through clock gating. As a processor model's design matures, smaller transistors, lower-voltage structures, and design experience may reduce energy consumption. Processor manufacturers usually release two power consumption numbers for a CPU: typical thermal power, which is measured under normal load (for instance, AMD's average CPU power) maximum thermal power, which is measured under a worst-case load For example, the Pentium 4 2.8 GHz has a 68.4 W typical thermal power and 85 W maximum thermal power. When the CPU is idle, it will draw far less than the typical thermal power. Datasheets normally contain the thermal design power (TDP), which is the maximum amount of heat generated by the CPU, which the cooling system in a computer is required to dissipate. Both Intel and Advanced Micro Devices (AMD) have defined TDP as the maximum heat generation for thermally significant periods, while running worst-case non-synthetic workloads; thus, TDP is not reflecting the actual maximum power of the processor. This ensures the computer will be able to handle essentially all applications without exceeding its thermal envelope, or requiring a cooling system for the maximum theoretical power (which would cost more but in favor of extra headroom for processing power). In many applications, the CPU and other components are idle much of the time, so idle power contributes significantly to overall system power usage. When the CPU uses power management features to reduce energy use, other components, such as the motherboard and chipset, take up a larger proportion of the computer's energy. In applications where the computer is often heavily loaded, such as scientific computing, performance per watt (how much computing the CPU does per unit of energy) becomes more significant. CPUs typically use a significant portion of the power consumed by the computer. Other major uses include fast video cards, which contain graphics processing units, and power supplies. In laptops, the LCD's backlight also uses a significant portion of overall power. While energy-saving features have been instituted in personal computers for when they are idle, the overall consumption of today's high-performance CPUs is considerable. This is in strong contrast with the much lower energy consumption of CPUs designed for low-power devices. Sources There are several factors contributing to the CPU power consumption; they include dynamic power consumption, short-circuit power consumption, and power loss due to transistor leakage currents: The dynamic power consumption originates from the activity of logic gates inside a CPU. When the logic gates toggle, energy is flowing as the capacitors inside them are charged and discharged. The dynamic power consumed by a CPU is approximately proportional to the CPU frequency, and to the square of the CPU voltage: where is the switched load capacitance, is frequency, is voltage. When logic gates toggle, some transistors inside may change states. As this takes a finite amount of time, it may happen that for a very brief amount of time some transistors are conducting simultaneously. A direct path between the source and ground then results in some short-circuit power loss (). The magnitude of this power is dependent on the logic gate, and is rather complex to model on a macro level. Power consumption due to leakage power () emanates at a micro-level in transistors. Small amounts of currents are always flowing between the differently doped parts of the transistor. The magnitude of these currents depend on the state of the transistor, its dimensions, physical properties and sometimes temperature. The total amount of leakage currents tends to inflate for increasing temperature and decreasing transistor sizes. Both dynamic and short-circuit power consumption are dependent on the clock frequency, while the leakage current is dependent on the CPU supply voltage. It has been shown that the energy consumption of a program shows convex energy behavior, meaning that there exists an optimal CPU frequency at which energy consumption is minimal for the work done. Reduction Power consumption can be reduced in several ways, including the following: Voltage reduction dual-voltage CPUs, dynamic voltage scaling, undervolting, etc. Frequency reduction underclocking, dynamic frequency scaling, etc. Capacitance reduction increasingly integrated circuits that replace PCB traces between two chips with relatively lower-capacitance on-chip metal interconnect between two sections of a single integrated chip; low-k dielectric, etc. Power gating techniques such as clock gating and globally asynchronous locally synchronous, which can be thought of as reducing the capacitance switched on each clock tick, or can be thought of as locally reducing the clock frequency in some sections of the chip. Various techniques to reduce the switching activity number of transitions the CPU drives into off-chip data buses, such as non-multiplexed address bus, bus encoding such as Gray code addressing, or value cache encoding such as power protocol. Sometimes an "activity factor" (A) is put into the above equation to reflect activity. Sacrificing transistor density for higher frequencies. Layering heat-conduction zones within the CPU framework ("Christmassing the Gate"). Recycling at least some of that energy stored in the capacitors (rather than dissipating it as heat in transistors) adiabatic circuit, energy recovery logic, etc. Optimizing machine code - by implementing compiler optimizations that schedules clusters of instructions using common components, the CPU power used to run an application can be significantly reduced. Clock frequencies and multi-core chip designs Historically, processor manufacturers consistently delivered increases in clock rates and instruction-level parallelism, so that single-threaded code executed faster on newer processors with no modification. More recently, in order to manage CPU power dissipation, processor makers favor multi-core chip designs, thus software needs to be written in a multi-threaded or multi-process manner to take full advantage of such hardware. Many multi-threaded development paradigms introduce overhead, and will not see a linear increase in speed when compared to the number of processors. This is particularly true while accessing shared or dependent resources, due to lock contention. This effect becomes more noticeable as the number of processors increases. Recently, IBM has been exploring ways to distribute computing power more efficiently by mimicking the distributional properties of the human brain. Processor overheating Processor can be damaged from overheating, but vendors protect processors with operational safeguards such as throttling and automatic shutdown. When a core exceeds the set throttle temperature, processors can reduce power to maintain a safe temperature level and if the processor is unable to maintain a safe operating temperature through throttling actions, it will automatically shut down to prevent permanent damage. See also Autonomous peripheral operation Advanced Configuration and Power Interface (ACPI) Glitch removal Green computing IT energy management List of CPU power dissipation Low-power electronics Moore's law Overclocking Performance per watt Power analysis Power dissipation PowerTOP References Further reading http://developer.intel.com/design/itanium2/documentation.htm#datasheets http://www.intel.com/pressroom/kits/quickreffam.htm http://www.intel.com/design/mobile/datashts/24297301.pdf http://www.intel.com/design/intarch/prodbref/27331106.pdf http://www.via.com.tw/en/products/processors/c7-d/ https://web.archive.org/web/20090216190358/http://mbsg.intel.com/mbsg/glossary.aspx http://download.intel.com/design/Xeon/datashts/25213506.pdf http://www.intel.com/Assets/en_US/PDF/datasheet/313079.pdf, page 12 http://support.amd.com/us/Processor_TechDocs/43374.pdf, pages 10 and 80. External links CPU Reference for all vendors. Process node, die size, speed, power, instruction set, etc. Processor Electrical Specifications SizingLounge online calculation tool for server energy costs For specification on Intel processors Making x86 Run Cool, 2001-04-15, by Paul DeMone Central processing unit Electric power

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Battery management system A battery management system (BMS) is any electronic system that manages a rechargeable battery (cell or battery pack), such as by protecting the battery from operating outside its safe operating area, monitoring its state, calculating secondary data, reporting that data, controlling its environment, authenticating it and / or balancing it. A battery pack built together with a battery management system with an external communication data bus is a smart battery pack. A smart battery pack must be charged by a smart battery charger. Functions Monitor A BMS may monitor the state of the battery as represented by various items, such as: Voltage: total voltage, voltages of individual cells, or voltage of periodic taps Temperature: average temperature, coolant intake temperature, coolant output temperature, or temperatures of individual cells Coolant flow: for air or fluid cooled batteries Current: current in or out of the battery Electric vehicle systems: energy recovery The BMS will also control the recharging of the battery by redirecting the recovered energy (i.e.- from regenerative braking) back into the battery pack (typically composed of a number of battery modules, each composed of a number of cells). Battery thermal management systems can be either passive or active, and the cooling medium can either be air, liquid, or some form of phase change. Air cooling is advantageous in its simplicity. Such systems can be passive, relying only on the convection of the surrounding air, or active, utilizing fans for airflow. Commercially, the Honda Insight and Toyota Prius both utilize active air cooling of their battery systems. The major disadvantage of air cooling is its inefficiency. Large amounts of power must be used to operate the cooling mechanism, far more than active liquid cooling. The additional components of the cooling mechanism also add weight to the BMS, reducing the efficiency of batteries used for transportation. Liquid cooling has a higher natural cooling potential than air cooling as liquid coolants tend to have higher thermal conductivities than air. The batteries can either be directly submerged in the coolant or coolant can flow through the BMS without directly contacting the battery. Indirect cooling has the potential to create large thermal gradients across the BMS due to the increased length of the cooling channels. This can be reduced by pumping the coolant faster through the system, creating a tradeoff between pumping speed and thermal consistency. Computation Additionally, a BMS may calculate values based on the below items, such as: Voltage: minimum and maximum cell voltage State of charge (SOC) or depth of discharge (DOD), to indicate the charge level of the battery State of health (SOH), a variously-defined measurement of the remaining capacity of the battery as % of the original capacity State of power (SOP), the amount of power available for a defined time interval given the current power usage, temperature and other conditions State of Safety (SOS) Maximum charge current as a charge current limit (CCL) Maximum discharge current as a discharge current limit (DCL) Energy [kWh] delivered since last charge or charge cycle Internal impedance of a cell (to determine open circuit voltage) Charge [Ah] delivered or stored (sometimes this feature is called Coulomb counter) Total energy delivered since first use Total operating time since first use Total number of cycles Temperature Monitoring Communication The central controller of a BMS communicates internally with its hardware operating at a cell level, or externally with high level hardware such as laptops or an HMI. High level external communication are simple and use several methods: Different types of serial communications. CAN bus communications, commonly used in automotive environments. Different types of Wireless communications. Low voltage centralized BMSs mostly do not have any internal communications. Distributed or modular BMSs must use some low level internal cell-controller (Modular architecture) or controller-controller (Distributed architecture) communication. These types of communications are difficult, especially for high voltage systems. The problem is voltage shift between cells. The first cell ground signal may be hundreds of volts higher than the other cell ground signal. Apart from software protocols, there are two known ways of hardware communication for voltage shifting systems, Optical-isolator and wireless communication. Another restriction for internal communications is the maximum number of cells. For modular architecture most hardware is limited to maximum 255 nodes. For high voltage systems the seeking time of all cells is another restriction, limiting minimum bus speeds and losing some hardware options. Cost of modular systems is important, because it may be comparable to the cell price. Combination of hardware and software restrictions results to be a few options for internal communication: Isolated serial communications wireless serial communications To bypass power limitations of existing USB cables due to heat from electrical current, communication protocols implemented in mobile phone chargers for negotiating an elevated voltage have been developed, the most widely used of which are Qualcomm Quick Charge and MediaTek Pump Express. "VOOC" by Oppo (also branded as "Dash Charge" with "OnePlus") increases the current instead of voltage with the aim to reduce heat produced in the device from internally converting an elevated voltage down to the battery's terminal charging voltage, which however makes it incompatible with existing USB cables and relies on special high-current USB cables with accordingly thicker copper wires. More recently, the USB Power Delivery standard aims for an universal negotiation protocol across devices of up to 240 Watts. Protection A BMS may protect its battery by preventing it from operating outside its safe operating area, such as: Over-current (may be different in charging and discharging modes) Over-voltage (during charging), especially important for lead–acid and Li-ion cells Under-voltage (during discharging) Over-temperature Under-temperature Over-pressure (NiMH batteries) Ground fault or leakage current detection (system monitoring that the high voltage battery is electrically disconnected from any conductive object touchable to use like vehicle body) The BMS may prevent operation outside the battery's safe operating area by: Including an internal switch (such as a relay or solid state device) which is opened if the battery is operated outside its safe operating area Requesting the devices to which the battery is connected to reduce or even terminate using the battery. Actively controlling the environment, such as through heaters, fans, air conditioning or liquid cooling Battery connection to load circuit A BMS may also feature a precharge system allowing a safe way to connect the battery to different loads and eliminating the excessive inrush currents to load capacitors. The connection to loads is normally controlled through electromagnetic relays called contactors. The precharge circuit can be either power resistors connected in series with the loads until the capacitors are charged. Alternatively, a switched mode power supply connected in parallel to loads can be used to charge the voltage of the load circuit up to a level close enough to battery voltage in order to allow closing the contactors between battery and load circuit. A BMS may have a circuit that can check whether a relay is already closed before precharging (due to welding for example) to prevent inrush currents to occur. Balancing In order to maximize the battery's capacity, and to prevent localized under-charging or over-charging, the BMS may actively ensure that all the cells that compose the battery are kept at the same voltage or State of Charge, through balancing. The BMS can balance the cells by: Wasting energy from the most charged cells by connecting them to a load (such as through passive regulators) Shuffling energy from the most charged cells to the least charged cells (balancers) Reducing the charging current to a sufficiently low level that will not damage fully charged cells, while less charged cells may continue to charge (does not apply to Lithium chemistry cells) Topologies BMS technology varies in complexity and performance: Simple passive regulators achieve balancing across batteries or cells by bypassing charging current when the cell's voltage reaches a certain level. The cell voltage is a poor indicator of the cell's SOC (and for certain Lithium chemistries such as LiFePO4 it is no indicator at all), thus, making cell voltages equal using passive regulators does not balance SOC, which is the goal of a BMS. Therefore, such devices, while certainly beneficial, have severe limitations in their effectiveness. Active regulators intelligently turning on and off a load when appropriate, again to achieve balancing. If only the cell voltage is used as a parameter to enable the active regulators, the same constraints noted above for passive regulators apply. A complete BMS also reports the state of the battery to a display, and protects the battery. BMS topologies fall in 3 categories: Centralized: a single controller is connected to the battery cells through a multitude of wires Distributed: a BMS board is installed at each cell, with just a single communication cable between the battery and a controller Modular: a few controllers, each handling a certain number of cells, with communication between the controllers Centralized BMSs are most economical, least expandable, and are plagued by a multitude of wires. Distributed BMSs are the most expensive, simplest to install, and offer the cleanest assembly. Modular BMSs offer a compromise of the features and problems of the other two topologies. The requirements for a BMS in mobile applications (such as electric vehicles) and stationary applications (like stand-by UPSs in a server room) are quite different, especially from the space and weight constraint requirements, so the hardware and software implementations must be tailored to the specific use. In the case of electric or hybrid vehicles, the BMS is only a subsystem and cannot work as a standalone device. It must communicate with at least a charger (or charging infrastructure), a load, thermal management and emergency shutdown subsystems. Therefore, in a good vehicle design the BMS is tightly integrated with those subsystems. Some small mobile applications (such as medical equipment carts, motorized wheelchairs, scooters, and fork lifts) often have external charging hardware, however the on-board BMS must still have tight design integration with the external charger. Various Battery balancing methods are in use, some of them based on state of charge theory. See also Battery balancing Smart battery Battery charger Charge controller References External links Electropaedia on Battery Management Systems NREL Energy Storage Systems Evaluation Modular Approach for Continuous Cell-Level Balancing to Improve Performance of Large Battery Packs, National Renewable Energy Laboratory, September 2014 A Modular Battery Management System for HEVs, National Renewable Energy Laboratory, 2002 Energy conversion Battery charging Embedded operating systems

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Backup battery A backup battery provides power to a system when the primary source of power is unavailable. Backup batteries range from small single cells to retain clock time and date in computers, up to large battery room facilities that power uninterruptible power supply systems for large data centers. Small backup batteries may be primary cells; rechargeable backup batteries are kept charged by the prime power supply. Examples Aircraft emergency batteries Backup batteries in aircraft keep essential instruments and devices running in the event of an engine power failure. Each aircraft has enough power in the backup batteries to facilitate a safe landing. The batteries keeping navigation, ELUs (emergency lighting units), emergency pressure or oxygen systems running at altitude, and radio equipment operational. Larger aircraft have control surfaces that run on these backups as well. Aircraft batteries are either nickel-cadmium or valve-regulated lead acid type. The battery keeps all necessary items running for between 30 minutes and 3 hours. Large aircraft may have a ram air turbine to provide additional power during engine failures. Burglar alarms Backup batteries are almost always used in burglar alarms. The backup battery prevents the burglar from disabling the alarm by turning off power to the building. Additionally these batteries power the remote cellular phone systems that thwart phone line snipping as well. The backup battery usually has a lifespan of 3-10 years depending on the make and model, and so if the battery runs flat, there is only one main source of power to the whole system which is the mains power. Should this fail as well (for example, a power cut), it usually triggers a third backup battery located in the bellboxes on the outside of the building which simply triggers the bell or siren. This however means that the alarm cannot be stopped in any way apart from physically going outside to the bellbox and disabling the siren. It is also why if there is a power outage in the area, most burglar alarms do start ringing and cannot be realistically stopped until the main power is restored. Computers Modern personal computer motherboards have a backup battery to run the real-time clock circuit and retain configuration memory while the system is turned off. This is often called the CMOS battery or BIOS battery. The original IBM AT through to the PS/2 range, used a relatively large primary lithium battery, compared to later models, to retain the clock and configuration memory. These early machines required the backup battery to be replaced periodically due to the relatively large power consumption. Some manufacturers of clone machines used a rechargeable battery to avoid the problems that could be created by a failing battery. Modern systems use a coin style primary battery. In these later machines, the current draw is almost negligible and the primary batteries usually outlast the system that they support. It is rare to find rechargeable batteries in such systems. Backup batteries are used in uninterruptible power supplies (UPS), and provide power to the computers they supply for a variable period after a power failure, usually long enough to at least allow the computer to be shut down gracefully. These batteries are often large valve regulated lead-acid batteries in smaller or portable systems. Data center UPS backup batteries may be wet cell lead-acid or nickel cadmium batteries, with lithium ion cells available in some ratings. Server-grade disk array controllers often contain onboard disk buffer, and provide an option for a "backup battery unit" (BBU) to maintain the contents of this cache after power loss. If this battery is present, disk writes can be considered completed when they reach the cache, thus speeding up I/O throughput by not waiting for the hard drive. This operation mode is called "write-back caching". Telephony A local backup battery unit is necessary in some telephony and combined telephony/data applications built with use of digital passive optical networks. In such networks there are active units on telephone exchange side and on the user side, but nodes between them are all passive in the meaning of electrical power usage. So, if a building (such as an apartment house) loses power, the network continues to function. The user side must have standby power since operating power isn't transferred over data optical line. Telecommunications networks and data centers A valve-regulated lead-acid battery (VRLA) is a battery type that is popular in telecommunications network environments as a reliable backup power source. VRLA batteries are used in the outside plant at locations such as Controlled Environmental Vaults (CEVs), Electronic Equipment Enclosures (EEEs), and huts, and in uncontrolled structures such as cabinets. VRLA Battery String Certification Levels Based on Requirements for Safety and Performance, is a new industry-approved set of VRLA requirements that provides a three-level compliance system. The compliance system provides a common framework for evaluating and qualifying various valve-regulated lead-acid battery technologies. The framework intends to alleviate the complexities associated with product introduction and qualification. For a VRLA, the quality system employed by the manufacturer is an important key to the overall reliability of it. The manufacturing processes, test and inspection procedures, and quality program used by a manufacturer should be adequate to ensure that the final product meets the needs of the end user, the application, and industry-accepted standards and processes (i.e., ANSI/IEC, TL9000, and Generic Requirements for the Physical Design and Manufacture of Telecommunications Products and Equipment. Video game cartridges Cartridge-based video games sometimes contain a battery which is used to preserve the contents of a small RAM chip on which saved games and/or high scores are recorded. Hospitals Power failure in a hospital would result in life-threatening conditions for patients. Patients undergoing surgery or on life support are reliant on a consistent power supply. Backup generators or batteries supply power to critical equipment until main power can be restored. Power Stations Power failure in a power station that produces electricity would result in a blackout situation that would cause irreparable damage to equipment such as the turbine-generator. The safety of power station employees is a major concern during an unscheduled power outage at a power plant. A bank of large station backup batteries are used to power uninterruptible power supplies as well as directly power emergency oil pumps for up to 8 hours while normal power is being restored to the power station. Tesla, Inc installed the world's largest lithium ion battery pack for the government of South Australia in 2017; to help alleviate energy (electricity) blackouts in the state. Tesla met the guarantee by Elon Musk of installation in 100 days or it would be free. See also List of battery types Reserve battery References Battery applications Electric power

laptop Battery Life

Power management Power management is a feature of some electrical appliances, especially copiers, computers, computer CPUs, computer GPUs and computer peripherals such as monitors and printers, that turns off the power or switches the system to a low-power state when inactive. In computing this is known as PC power management and is built around a standard called ACPI, this supersedes APM. All recent computers have ACPI support. Motivations PC power management for computer systems is desired for many reasons, particularly: Reduce overall energy consumption Prolong battery life for portable and embedded systems Reduce cooling requirements Reduce noise Reduce operating costs for energy and cooling Lower power consumption also means lower heat dissipation, which increases system stability, and less energy use, which saves money and reduces the impact on the environment. Processor level techniques The power management for microprocessors can be done over the whole processor, or in specific components, such as cache memory and main memory. With dynamic voltage scaling and dynamic frequency scaling, the CPU core voltage, clock rate, or both, can be altered to decrease power consumption at the price of potentially lower performance. This is sometimes done in real time to optimize the power-performance tradeoff. Examples: AMD Cool'n'Quiet AMD PowerNow! IBM EnergyScale Intel SpeedStep Transmeta LongRun and LongRun2 VIA LongHaul (PowerSaver) Additionally, processors can selectively power off internal circuitry (power gating). For example: Newer Intel Core processors support ultra-fine power control over the functional units within the processors. AMD CoolCore technology get more efficient performance by dynamically activating or turning off parts of the processor. Intel VRT technology split the chip into a 3.3V I/O section and a 2.9V core section. The lower core voltage reduces power consumption. Heterogenous computing ARM's big.LITTLE architecture can migrate processes between faster "big" cores and more power efficient "LITTLE" cores. Operating system level: hibernation When a computer system hibernates it saves the contents of the RAM to disk and powers down the machine. On startup it reloads the data. This allows the system to be completely powered off while in hibernate mode. This requires a file the size of the installed RAM to be placed on the hard disk, potentially using up space even when not in hibernate mode. Hibernate mode is enabled by default in some versions of Windows and can be disabled in order to recover this disk space. In GPUs Graphics processing unit (GPUs) are used together with a CPU to accelerate computing in variety of domains revolving around scientific, analytics, engineering, consumer and enterprise applications. All of this comes with some drawbacks, the high computing capability of GPUs comes at the cost of high power dissipation. Much research has been done over the power dissipation issue of GPUs and many techniques have been proposed to address this issue. Dynamic voltage scaling/dynamic frequency scaling (DVFS) and clock gating are two commonly used techniques for reducing dynamic power in GPUs. DVFS techniques Experiments show that conventional processor DVFS policy can achieve power reduction of embedded GPUs with reasonable performance degradation. New directions for designing effective DVFS schedulers for heterogeneous systems are also being explored. A heterogeneous CPU-GPU architecture, GreenGPU is presented which employs DVFS in a synchronized way, both for GPU and CPU. GreenGPU is implemented using the CUDA framework on a real physical testbed with Nvidia GeForce GPUs and AMD Phenom II CPUs. Experimentally it is shown that the GreenGPU achieves 21.04% average energy savings and outperforms several well-designed baselines. For the mainstream GPUs which are extensively used in all kinds of commercial and personal applications several DVFS techniques exist and are built into the GPUs alone, AMD PowerTune and AMD ZeroCore Power are the two dynamic frequency scaling technologies for AMD graphic cards. Practical tests showed that reclocking a GeForce GTX 480 can achieve a 28% lower power consumption while only decreasing performance by 1% for a given task. Power gating techniques Much research has been done on the dynamic power reduction with the use of DVFS techniques. However, as technology continues to shrink, leakage power will become a dominant factor. Power gating is a commonly used circuit technique to remove leakage by turning off the supply voltage of unused circuits. Power gating incurs energy overhead; therefore, unused circuits need to remain idle long enough to compensate this overheads. A novel micro-architectural technique for run-time power-gating caches of GPUs saves leakage energy. Based on experiments on 16 different GPU workloads, the average energy savings achieved by the proposed technique is 54%. Shaders are the most power hungry component of a GPU, a predictive shader shut down power gating technique achieves up to 46% leakage reduction on shader processors. The Predictive Shader Shutdown technique exploits workload variation across frames to eliminate leakage in shader clusters. Another technique called Deferred Geometry Pipeline seeks to minimize leakage in fixed-function geometry units by utilizing an imbalance between geometry and fragment computation across batches which removes up to 57% of the leakage in the fixed-function geometry units. A simple time-out power gating method can be applied to non-shader execution units which eliminates 83.3% of the leakage in non-shader execution units on average. All the three techniques stated above incur negligible performance degradation, less than 1%. See also 80 Plus Advanced power management (APM) Advanced Configuration and Power Interface (ACPI) Hibernate Sleep BatteryMAX (idle detection) Constant Awake Mode CPU power dissipation Dynamic frequency scaling Dynamic voltage scaling Energy Star Energy storage as a service (ESaaS) Green computing Low-power electronics pmset PowerTOP – diagnostic tool Run-time estimation of system and sub-system level power consumption Sleep Proxy Service Standby power The Green Grid Thermal design power VESA Display Power Management Signaling (DPMS) References External links Energy Star - Independent List of Products Energy Star - Low Carbon IT Campaign Energy Consumption Calculator Research Bibliography on Power Management Computers and the environment Energy conservation Computer hardware tuning

laptop Battery Life

Lithium-ion battery A lithium-ion battery or Li-ion battery is a type of rechargeable battery composed of cells in which lithium ions move from the negative electrode through an electrolyte to the positive electrode during discharge and back when charging. Li-ion cells use an intercalated lithium compound as the material at the positive electrode and typically graphite at the negative electrode. Li-ion batteries have a high energy density, no memory effect (other than LFP cells) and low self-discharge. Cells can be manufactured to either prioritize energy or power density. They can however be a safety hazard since they contain flammable electrolytes and if damaged or incorrectly charged can lead to explosions and fires. A prototype Li-ion battery was developed by Akira Yoshino in 1985, based on earlier research by John Goodenough, M. Stanley Whittingham, Rachid Yazami and Koichi Mizushima during the 1970s1980s, and then a commercial Li-ion battery was developed by a Sony and Asahi Kasei team led by Yoshio Nishi in 1991. Lithium-ion batteries are commonly used for portable electronics and electric vehicles and are growing in popularity for military and aerospace applications. Chemistry, performance, cost and safety characteristics vary across types of lithium-ion batteries. Handheld electronics mostly use lithium polymer batteries (with a polymer gel as electrolyte), a lithium cobalt oxide () cathode material, and a graphite anode, which together offer a high energy density. Lithium iron phosphate (), lithium manganese oxide ( spinel, or -based lithium rich layered materials, LMR-NMC), and lithium nickel manganese cobalt oxide ( or NMC) may offer longer lives and may have better rate capability. Such batteries are widely used for electric tools, medical equipment, and other roles. NMC and its derivatives are widely used in electric vehicles. Research areas for lithium-ion batteries include extending lifetime, increasing energy density, improving safety, reducing cost, and increasing charging speed, among others. Research has been under way in the area of non-flammable electrolytes as a pathway to increased safety based on the flammability and volatility of the organic solvents used in the typical electrolyte. Strategies include aqueous lithium-ion batteries, ceramic solid electrolytes, polymer electrolytes, ionic liquids, and heavily fluorinated systems. History Research on rechargeable Li-ion batteries dates to the 1960s; one of the earliest examples is a /Li battery developed by NASA in 1965. The breakthrough that produced the earliest form of the modern Li-ion battery was made by British chemist M. Stanley Whittingham in 1974, who first used titanium disulfide () as a cathode material, which has a layered structure that can take in lithium ions without significant changes to its crystal structure. Exxon tried to commercialize this battery in the late 1970s, but found the synthesis expensive and complex, as is sensitive to moisture and releases toxic gas on contact with water. More prohibitively, the batteries were also prone to spontaneously catch fire due to the presence of metallic lithium in the cells. In 1980, Koichi Mizushima and John B. Goodenough, after testing a range of alternative materials, replaced with lithium cobalt oxide (, or LCO), which has a similar layered structure but offers a higher voltage and is much more stable in air. This material would later be used in the first commercial Li-ion battery, although it did not, on its own, resolve the persistent issue of flammability. The same year, Rachid Yazami demonstrated the reversible electrochemical intercalation of lithium in graphite, and invented the lithium graphite electrode (anode). These early attempts to develop rechargeable Li-ion batteries used lithium metal anodes, which were ultimately abandoned due to safety concerns, as lithium metal is unstable and prone to dendrite formation, which can cause short-circuiting. The eventual solution was to use an intercalation anode, similar to that used for the cathode, which prevents the formation of lithium metal during battery charging. A variety of anode materials were studied; in 1987, Akira Yoshino patented what would become the first commercial lithium-ion battery using an anode of "soft carbon" (a charcoal-like material) along with Goodenough's previously reported LCO cathode and a carbonate ester-based electrolyte. In 1991, using Yoshino's design, Sony began producing and selling the world's first rechargeable lithium-ion batteries. The following year, a joint venture between Toshiba and Asashi Kasei Co. also released their own lithium-ion battery. Significant improvements in energy density were achieved in the 1990s by replacing the soft carbon anode first with hard carbon and later with graphite, a concept originally proposed by Jürgen Otto Besenhard in 1974 but considered unfeasible due to unresolved incompatibilities with the electrolytes then in use. In 2012 John B. Goodenough, Rachid Yazami and Akira Yoshino received the 2012 IEEE Medal for Environmental and Safety Technologies for developing the lithium-ion battery; Goodenough, Whittingham and Yoshino were awarded the 2019 Nobel Prize in Chemistry "for the development of lithium-ion batteries". In 2010, global lithium-ion battery production capacity was 20 gigawatt-hours. By 2016, it was 28 GWh, with 16.4 GWh in China. Production in 2021 is estimated by various sources to be between 200 and 600 GWh, and predictions for 2023 range from 400 to 1,100 GWh. Design Generally, the negative electrode of a conventional lithium-ion cell is made from carbon. The positive electrode is typically a metal oxide. The electrolyte is a lithium salt in an organic solvent. The electrochemical roles of the electrodes reverse between anode and cathode, depending on the direction of current flow through the cell. The most common commercially used anode (negative electrode) is graphite, which in its fully lithiated state of LiC6 correlates to a maximal capacity of 1339 C/g (372 mAh/g). The positive electrode is generally one of three materials: a layered oxide (such as lithium cobalt oxide), a polyanion (such as lithium iron phosphate) or a spinel (such as lithium manganese oxide). More experimental materials include graphene-containing electrodes, although these remain far from commercially viable due to their high cost. Lithium reacts vigorously with water to form lithium hydroxide (LiOH) and hydrogen gas. Thus, a non-aqueous electrolyte is typically used, and a sealed container rigidly excludes moisture from the battery pack. The non-aqueous electrolyte is typically a mixture of organic carbonates such as ethylene carbonate or diethyl carbonate containing complexes of lithium ions. The salt is almost always lithium hexafluorophosphate (), which combines good ionic conductivity with chemical and electrochemical stability. Other salts like lithium perchlorate (), lithium tetrafluoroborate (), and lithium bis(trifluoromethanesulfonyl)imide () are frequently used in research for reasons of cost or convenience but are not usable in commercial cells. Depending on materials choices, the voltage, energy density, life, and safety of a lithium-ion cell can change dramatically. Current effort has been exploring the use of novel architectures using nanotechnology to improve performance. Areas of interest include nano-scale electrode materials and alternative electrode structures. The increasing demand for batteries has led vendors and academics to focus on improving the energy density, operating temperature, safety, durability, charging time, output power, elimination of cobalt requirements, and cost of lithium-ion battery technology. Electrochemistry The reactants in the electrochemical reactions in a lithium-ion cell are materials of anode and cathode, both of which are compounds containing lithium atoms. During charge, an oxidation half-reaction at the anode produces positively charged lithium ions and negatively charged electrons. The oxidation half-reaction may also produce uncharged material that remains at the anode. Lithium ions move through the electrolyte, electrons move through the external circuit, and then they recombine at the cathode (together with the cathode material) in a reduction half-reaction. The electrolyte and external circuit provide conductive media for lithium ions and electrons, respectively, but do not partake in the electrochemical reaction. During discharge, electrons flow from the negative electrode (anode) towards the positive electrode (cathode) through the external circuit. The reactions during discharge lower the chemical potential of the cell, so discharging transfers energy from the cell to wherever the electric current dissipates its energy, mostly in the external circuit. During charging these reactions and transports go in the opposite direction: electrons move from the positive electrode to the negative electrode through the external circuit. To charge the cell the external circuit has to provide electric energy. This energy is then stored as chemical energy in the cell (with some loss, e. g. due to coulombic efficiency lower than 1). Both electrodes allow lithium ions to move in and out of their structures with a process called insertion (intercalation) or extraction (deintercalation), respectively. As the lithium ions "rock" back and forth between the two electrodes, these batteries are also known as "rocking-chair batteries" or "swing batteries" (a term given by some European industries). The following equations exemplify the chemistry. The positive electrode (cathode) half-reaction in the lithium-doped cobalt oxide substrate is CoO2 + Li+ + e- <=> LiCoO2 The negative electrode (anode) half-reaction for the graphite is LiC6 <=> C6 + Li+ + e^- The full reaction (left to right: discharging, right to left: charging) being LiC6 + CoO2 <=> C6 + LiCoO2 The overall reaction has its limits. Overdischarging supersaturates lithium cobalt oxide, leading to the production of lithium oxide, possibly by the following irreversible reaction: Li+ + e^- + LiCoO2 -> Li2O + CoO Overcharging up to 5.2 volts leads to the synthesis of cobalt (IV) oxide, as evidenced by x-ray diffraction: LiCoO2 -> Li+ + CoO2 + e^- In a lithium-ion cell, the lithium ions are transported to and from the positive or negative electrodes by oxidizing the transition metal, cobalt (Co), in from to during charge, and reducing from to during discharge. The cobalt electrode reaction is only reversible for x < 0.5 (x in mole units), limiting the depth of discharge allowable. This chemistry was used in the Li-ion cells developed by Sony in 1990. The cell's energy is equal to the voltage times the charge. Each gram of lithium represents Faraday's constant/6.941, or 13,901 coulombs. At 3 V, this gives 41.7 kJ per gram of lithium, or 11.6 kWh per kilogram of lithium. This is a bit more than the heat of combustion of gasoline but does not consider the other materials that go into a lithium battery and that make lithium batteries many times heavier per unit of energy. The cell voltages given in the Electrochemistry section are larger than the potential at which aqueous solutions will electrolyze. Liquid electrolytes in lithium-ion batteries consist of lithium salts, such as , or in an organic solvent, such as ethylene carbonate, dimethyl carbonate, and diethyl carbonate. A liquid electrolyte acts as a conductive pathway for the movement of cations passing from the negative to the positive electrodes during discharge. Typical conductivities of liquid electrolyte at room temperature () are in the range of 10 mS/cm, increasing by approximately 30–40% at and decreasing slightly at . The combination of linear and cyclic carbonates (e.g., ethylene carbonate (EC) and dimethyl carbonate (DMC)) offers high conductivity and solid electrolyte interphase (SEI)-forming ability. Organic solvents easily decompose on the negative electrodes during charge. When appropriate organic solvents are used as the electrolyte, the solvent decomposes on initial charging and forms a solid layer called the solid electrolyte interphase, which is electrically insulating, yet provides significant ionic conductivity. The interphase prevents further decomposition of the electrolyte after the second charge. For example, ethylene carbonate is decomposed at a relatively high voltage, 0.7 V vs. lithium, and forms a dense and stable interface. Composite electrolytes based on POE (poly(oxyethylene)) provide a relatively stable interface. It can be either solid (high molecular weight) and be applied in dry Li-polymer cells, or liquid (low molecular weight) and be applied in regular Li-ion cells. Room-temperature ionic liquids (RTILs) are another approach to limiting the flammability and volatility of organic electrolytes. Recent advances in battery technology involve using a solid as the electrolyte material. The most promising of these are ceramics. Solid ceramic electrolytes are mostly lithium metal oxides, which allow lithium-ion transport through the solid more readily due to the intrinsic lithium. The main benefit of solid electrolytes is that there is no risk of leaks, which is a serious safety issue for batteries with liquid electrolytes. Solid ceramic electrolytes can be further broken down into two main categories: ceramic and glassy. Ceramic solid electrolytes are highly ordered compounds with crystal structures that usually have ion transport channels. Common ceramic electrolytes are lithium super ion conductors (LISICON) and perovskites. Glassy solid electrolytes are amorphous atomic structures made up of similar elements to ceramic solid electrolytes but have higher conductivities overall due to higher conductivity at grain boundaries. Both glassy and ceramic electrolytes can be made more ionically conductive by substituting sulfur for oxygen. The larger radius of sulfur and its higher ability to be polarized allow higher conductivity of lithium. This contributes to conductivities of solid electrolytes are nearing parity with their liquid counterparts, with most on the order of 0.1 mS/cm and the best at 10 mS/cm. An efficient and economic way to tune targeted electrolytes properties is by adding a third component in small concentrations, known as an additive. By adding the additive in small amounts, the bulk properties of the electrolyte system will not be affected whilst the targeted property can be significantly improved. The numerous additives that have been tested can be divided into the following three distinct categories: (1) those used for SEI chemistry modifications; (2) those used for enhancing the ion conduction properties; (3) those used for improving the safety of the cell (e.g. prevent overcharging). Charging and discharging During discharge, lithium ions () carry the current within the battery cell from the negative to the positive electrode, through the non-aqueous electrolyte and separator diaphragm. During charging, an external electrical power source (the charging circuit) applies an over-voltage (a higher voltage than the battery produces, of the same polarity), forcing a charging current to flow within each cell from the positive to the negative electrode, i.e., in the reverse direction of a discharge current under normal conditions. The lithium ions then migrate from the positive to the negative electrode, where they become embedded in the porous electrode material in a process known as intercalation. Energy losses arising from electrical contact resistance at interfaces between electrode layers and at contacts with current collectors can be as high as 20% of the entire energy flow of batteries under typical operating conditions. The charging procedures for single Li-ion cells, and complete Li-ion batteries, are slightly different: A single Li-ion cell is charged in two stages: Constant current (CC). Constant voltage (CV). A Li-ion battery (a set of Li-ion cells in series) is charged in three stages: Constant current. Balance (not required once a battery is balanced). Constant voltage. During the constant current phase, the charger applies a constant current to the battery at a steadily increasing voltage, until the voltage limit per cell is reached. During the balance phase, the charger reduces the charging current (or cycles the charging on and off to reduce the average current) while the state of charge of individual cells is brought to the same level by a balancing circuit, until the battery is balanced. Some fast chargers skip this stage. Some chargers accomplish the balance by charging each cell independently. During the constant voltage phase, the charger applies a voltage equal to the maximum cell voltage times the number of cells in series to the battery, as the current gradually declines towards 0, until the current is below a set threshold of about 3% of initial constant charge current. Periodic topping charge about once per 500 hours. Top charging is recommended to be initiated when voltage goes below Failure to follow current and voltage limitations can result in an explosion. Charging temperature limits for Li-ion are stricter than the operating limits. Lithium-ion chemistry performs well at elevated temperatures but prolonged exposure to heat reduces battery life. Li‑ion batteries offer good charging performance at cooler temperatures and may even allow 'fast-charging' within a temperature range of . Charging should be performed within this temperature range. At temperatures from 0 to 5 °C charging is possible, but the charge current should be reduced. During a low-temperature charge, the slight temperature rise above ambient due to the internal cell resistance is beneficial. High temperatures during charging may lead to battery degradation and charging at temperatures above 45 °C will degrade battery performance, whereas at lower temperatures the internal resistance of the battery may increase, resulting in slower charging and thus longer charging times. Consumer-grade lithium-ion batteries should not be charged at temperatures below . Although a battery pack may appear to be charging normally, electroplating of metallic lithium can occur at the negative electrode during a subfreezing charge, and may not be removable even by repeated cycling. Most devices equipped with Li-ion batteries do not allow charging outside of 0–45 °C for safety reasons, except for mobile phones that may allow some degree of charging when they detect an emergency call in progress. Batteries gradually self-discharge even if not connected and delivering current. Li-ion rechargeable batteries have a self-discharge rate typically stated by manufacturers to be 1.5–2% per month. The rate increases with temperature and state of charge. A 2004 study found that for most cycling conditions self-discharge was primarily time-dependent; however, after several months of stand on open circuit or float charge, state-of-charge dependent losses became significant. The self-discharge rate did not increase monotonically with state-of-charge, but dropped somewhat at intermediate states of charge. Self-discharge rates may increase as batteries age. In 1999, self-discharge per month was measured at 8% at 21 °C, 15% at 40 °C, 31% at 60 °C. By 2007, monthly self-discharge rate was estimated at 2% to 3%, and 2–3% by 2016. By comparison, the self-discharge rate for NiMH batteries dropped, as of 2017, from up to 30% per month for previously common cells to about 0.08–0.33% per month for low self-discharge NiMH batteries, and is about 10% per month in NiCd batteries. Cathode Cathode materials are generally constructed from or . The cobalt-based material develops a pseudo tetrahedral structure that allows for two-dimensional lithium-ion diffusion. The cobalt-based cathodes are ideal due to their high theoretical specific heat capacity, high volumetric capacity, low self-discharge, high discharge voltage, and good cycling performance. Limitations include the high cost of the material, and low thermal stability. The manganese-based materials adopt a cubic crystal lattice system, which allows for three-dimensional lithium-ion diffusion. Manganese cathodes are attractive because manganese is cheaper and because it could theoretically be used to make a more efficient, longer-lasting battery if its limitations could be overcome. Limitations include the tendency for manganese to dissolve into the electrolyte during cycling leading to poor cycling stability for the cathode. Cobalt-based cathodes are the most common, however other materials are being researched with the goal of lowering costs and improving cell life. , is a candidate for large-scale production of lithium-ion batteries such as electric vehicle applications due to its low cost, excellent safety, and high cycle durability. For example, Sony Fortelion batteries have retained 74% of their capacity after 8000 cycles with 100% discharge. A carbon conductive agent is required to overcome its low electrical conductivity. Anode Negative electrode materials are traditionally constructed from graphite and other carbon materials, although newer silicon-based materials are being increasingly used (see Nanowire battery). These materials are used because they are abundant and are electrically conducting and can intercalate lithium ions to store electrical charge with modest volume expansion (~10%). Graphite is the dominant material because of its low voltage and excellent performance. Various materials have been introduced, but their higher voltage reduces low energy density. Low voltage is the key requirement; otherwise, the excess capacity is useless in terms of energy density. As graphite is limited to a maximum capacity of 372 mAh/g much research has been dedicated to the development of materials that exhibit higher theoretical capacities, and overcoming the technical challenges that presently encumber their implementation. The extensive 2007 Review Article by Kasavajjula et al. summarizes early research on silicon-based anodes for lithium-ion secondary cells. In particular, Hong Li et al. showed in 2000 that the electrochemical insertion of lithium ions in silicon nanoparticles and silicon nanowires leads to the formation of an amorphous Li-Si alloy. The same year, Bo Gao and his doctoral advisor, Professor Otto Zhou described the cycling of electrochemical cells with anodes comprising silicon nanowires, with a reversible capacity ranging from at least approximately 900 to 1500 mAh/g. To improve stability of the lithium anode, several approaches of installing a protective layer have been suggested. Silicon is beginning to be looked at as an anode material because it can accommodate significantly more lithium ions, storing up to 10 times the electric charge, however this alloying between lithium and silicon results in significant volume expansion (ca. 400%), which causes catastrophic failure for the cell. Silicon has been used as an anode material but the insertion and extraction of \scriptstyle Li+ can create cracks in the material. These cracks expose the Si surface to an electrolyte, causing decomposition and the formation of a solid electrolyte interphase (SEI) on the new Si surface (crumpled graphene encapsulated Si nanoparticles). This SEI will continue to grow thicker, deplete the available \scriptstyle Li+, and degrade the capacity and cycling stability of the anode. There have been attempts using various Si nanostructures that include nanowires, nanotubes, hollow spheres, nanoparticles, and nanoporous with the goal of them withstanding the (\scriptstyle Li+)-insertion/removal without significant cracking. Yet the formation of SEI on Si still occurs. So a coating would be logical, in order to account for any increase in the volume of the Si, a tight surface coating is not viable. In 2012, researchers from Northwestern University created an approach to encapsulate Si nanoparticles using crumpled r-GO, graphene oxide. This method allows for protection of the Si nanoparticles from the electrolyte as well as allow for the expansion of Si without expansion due to the wrinkles and creases in the graphene balls. These capsules began as an aqueous dispersion of GO and Si particles and are then nebulized into a mist of droplets that pass through a tube furnace. As they pass through the liquid evaporates, the GO sheets are pulled into a crumpled ball by capillary forces and encapsulate Si particles with them. There is a galvanostatic charge/discharge profile of 0.05 \scriptstyle mA/cm^2 to 1 \scriptstyle mA/cm^2 for current densities 0.2 to 4 A/g, delivering 1200 mAh/g at 0.2 A/g. Electrolyte Electrolyte alternatives have also played a significant role, for example the lithium polymer battery. Polymer electrolytes are promising for minimizing the dendrite formation of lithium. Polymers are supposed to prevent short circuits and maintain conductivity. The ions in the electrolyte diffuse because there are small changes in the electrolyte concentration. Linear diffusion is only considered here. The change in concentration c, as a function of time t and distance x, is In this equation, D is the diffusion coefficient for the lithium ion. It has a value of in the electrolyte. The value for ε, the porosity of the electrolyte, is 0.724. Formats Cells Li-ion cells (as distinct from entire batteries) are available in various shapes, which can generally be divided into four groups: Small cylindrical (solid body without terminals, such as those used in older laptop batteries) Large cylindrical (solid body with large threaded terminals) Flat or pouch (soft, flat body, such as those used in cell phones and newer laptops; these are lithium-ion polymer batteries. Rigid plastic case with large threaded terminals (such as electric vehicle traction packs) Cells with a cylindrical shape are made in a characteristic "swiss roll" manner (known as a "jelly roll" in the US), which means it is a single long 'sandwich' of the positive electrode, separator, negative electrode, and separator rolled into a single spool. The shape of the jelly roll in cylindrical cells can be approximated by an Archimedean spiral. One advantage of cylindrical cells compared to cells with stacked electrodes is the faster production speed. One disadvantage of cylindrical cells can be a large radial temperature gradient inside the cells developing at high discharge currents. The absence of a case gives pouch cells the highest gravimetric energy density; however, for many practical applications they still require an external means of containment to prevent expansion when their state of charge (SOC) level is high, and for general structural stability of the battery pack of which they are part. Both rigid plastic and pouch-style cells are sometimes referred to as prismatic cells due to their rectangular shapes. Battery technology analyst Mark Ellis of Munro & Associates sees three basic Li-ion battery types used in modern (~2020) electric vehicle batteries at scale: cylindrical cells (e.g., Tesla), prismatic pouch (e.g., from LG), and prismatic can cells (e.g., from LG, Samsung, Panasonic, and others). Each form factor has characteristic advantages and disadvantages for EV use. Since 2011, several research groups have announced demonstrations of lithium-ion flow batteries that suspend the cathode or anode material in an aqueous or organic solution. In 2014, Panasonic created the smallest Li-ion cell. It is pin shaped. It has a diameter of 3.5mm and a weight of 0.6g. A coin cell form factor resembling that of ordinary lithium batteries is available since as early as 2006 for LiCoO2 cells, usually designated with a "LiR" prefix. Batteries A battery (also called a battery pack) consists of multiple connected lithium-ion cells. Battery packs for large consumer electronics like laptop computers also contain temperature sensors, voltage regulator circuits, voltage taps, and charge-state monitors. These components minimize safety risks like overheating and short circuiting. To power larger devices, such as electric cars, connecting many small batteries in a parallel circuit is more effective and more efficient than connecting a single large battery. Uses The vast majority of commercial Li-ion batteries are used in consumer electronics and electric vehicles. Such devices include: Portable devices: these include mobile phones and smartphones, laptops and tablets, digital cameras and camcorders, electronic cigarettes, handheld game consoles and torches (flashlights). Power tools: Li-ion batteries are used in tools such as cordless drills, sanders, saws, and a variety of garden equipment including whipper-snippers and hedge trimmers. Electric vehicles: electric vehicle batteries are used in electric cars, hybrid vehicles, electric motorcycles and scooters, electric bicycles, personal transporters and advanced electric wheelchairs. Also radio-controlled models, model aircraft, aircraft, and the Mars Curiosity rover. More niche uses include backup power in telecommunications applications. Lithium-ion batteries are also frequently discussed as a potential option for grid energy storage, although they are not yet cost-competitive at scale. Performance Because lithium-ion batteries can have a variety of positive and negative electrode materials, the energy density and voltage vary accordingly. The open-circuit voltage is higher than in aqueous batteries (such as lead–acid, nickel–metal hydride and nickel-cadmium). Internal resistance increases with both cycling and age, although this depends strongly on the voltage and temperature the batteries are stored at. Rising internal resistance causes the voltage at the terminals to drop under load, which reduces the maximum current draw. Eventually, increasing resistance will leave the battery in a state such that it can no longer support the normal discharge currents requested of it without unacceptable voltage drop or overheating. Batteries with a lithium iron phosphate positive and graphite negative electrodes have a nominal open-circuit voltage of 3.2 V and a typical charging voltage of 3.6 V. Lithium nickel manganese cobalt (NMC) oxide positives with graphite negatives have a 3.7 V nominal voltage with a 4.2 V maximum while charging. The charging procedure is performed at constant voltage with current-limiting circuitry (i.e., charging with constant current until a voltage of 4.2 V is reached in the cell and continuing with a constant voltage applied until the current drops close to zero). Typically, the charge is terminated at 3% of the initial charge current. In the past, lithium-ion batteries could not be fast-charged and needed at least two hours to fully charge. Current-generation cells can be fully charged in 45 minutes or less. In 2015 researchers demonstrated a small 600 mAh capacity battery charged to 68 percent capacity in two minutes and a 3,000 mAh battery charged to 48 percent capacity in five minutes. The latter battery has an energy density of 620 W·h/L. The device employed heteroatoms bonded to graphite molecules in the anode. Performance of manufactured batteries has improved over time. For example, from 1991 to 2005 the energy capacity per price of lithium ion batteries improved more than ten-fold, from 0.3 W·h per dollar to over 3 W·h per dollar. In the period from 2011 to 2017, progress has averaged 7.5% annually. Overall, between 1991 and 2018, prices for all types of lithium-ion cells (in dollars per kWh) fell approximately 97%. Over the same time period, energy density more than tripled. Efforts to increase energy density contributed significantly to cost reduction. Differently sized cells with similar chemistry can also have different energy densities. The 21700 cell has 50% more energy than the 18650 cell, and the bigger size reduces heat transfer to its surroundings. Lifespan Life of a lithium-ion battery is typically defined as the number of full charge-discharge cycles to reach a failure threshold in terms of capacity loss or impedance rise. Manufacturers' datasheet typically uses the word "cycle life" to specify lifespan in terms of the number of cycles to reach 80% of the rated battery capacity. Inactive storage of these batteries also reduces their capacity. Calendar life is used to represent the whole life cycle of battery involving both the cycle and inactive storage operations. Battery cycle life is affected by many different stress factors including temperature, discharge current, charge current, and state of charge ranges (depth of discharge). Batteries are not fully charged and discharged in real applications such as smartphones, laptops and electric cars and hence defining battery life via full discharge cycles can be misleading. To avoid this confusion, researchers sometimes use cumulative discharge defined as the total amount of charge (Ah) delivered by the battery during its entire life or equivalent full cycles, which represents the summation of the partial cycles as fractions of a full charge-discharge cycle. Battery degradation during storage is affected by temperature and battery state of charge (SOC) and a combination of full charge (100% SOC) and high temperature (usually > 50 °C) can result in sharp capacity drop and gas generation. Multiplying the battery cumulative discharge by the rated nominal Voltage gives the total energy delivered over the life of the battery. From this one can calculate the cost per kWh of the energy (including the cost of charging). Over their lifespan batteries degrade gradually leading to reduced capacity due to a variety of chemical and mechanical changes to the electrodes. Some of the most prominent mechanisms include the growth of resistive layers (solid electrolyte interphase, or SEI) on the electrode surfaces, lithium plating, mechanical cracking of the SEI layer or electrode particles, and thermal decomposition of electrolyte. Degradation is strongly temperature-dependent: degradation at room temperature is minimal but increases for batteries stored or used in hot or cold environments. High charge levels also hasten capacity loss. Batteries generate heat when being charged or discharged, especially at high currents. Large battery packs, such as those used in electric vehicles, are generally equipped with thermal management systems that maintain a temperature between and . Pouch and cylindrical cell temperatures depend linearly on the discharge current. Poor internal ventilation may increase temperatures. Loss rates vary by temperature: 6% loss at , 20% at , and 35% at . In contrast, the calendar life of cells is not affected by high charge states. The advent of the SEI layer improved performance, but increased vulnerability to thermal degradation. The layer is composed of electrolyte – carbonate reduction products that serve both as an ionic conductor and electronic insulator. It forms on both the anode and cathode and determines many performance parameters. Under typical conditions, such as room temperature and the absence of charge effects and contaminants, the layer reaches a fixed thickness after the first charge, allowing the device to operate for years. However, operation outside such parameters can degrade the device via several reactions. Lithium-ion batteries are prone to capacity fading over hundreds to thousands of cycles. It is by slow electrochemical processes, the formation of a solid-electrolyte inter phase (SEI) in the negative electrode. SEI forms in between the first charge and discharge and results in the consumption of lithium ions. The consumption of lithium ions reduces the charge and discharge efficiency of the electrode material. However, SEI film is organic solvent insoluble and hence it can be stable in organic electrolyte solutions. If proper additives are added to the electrolyte to promote SEI formation, the co-embedding of solvent molecules can be effectively prevented and the damage to electrode materials can be avoided. On the other hand, SEI is selective and allows lithium ions to pass through and forbids electrons to pass through. This guarantees the continuity of charging and discharging cycle. SEI hinders the further consumption of lithium ions and thus greatly improves the electrode, as well as the cycle performance and service life. New data has shown that exposure to heat and the use of fast charging promote the degradation of Li-ion batteries more than age and actual use. Charging Li-ion batteries beyond 80% can drastically accelerate battery degradation. Five common exothermic degradation reactions can occur: Chemical reduction of the electrolyte by the anode. Thermal decomposition of the electrolyte. Chemical oxidation of the electrolyte by the cathode. Thermal decomposition by the cathode and anode. Internal short circuit by charge effects. The SEI layer that forms on the anode is a mixture of lithium oxide, lithium fluoride and semicarbonates (e.g., lithium alkyl carbonates). At elevated temperatures, alkyl carbonates in the electrolyte decompose into insoluble  that increases film thickness, limiting anode efficiency. This increases cell impedance and reduces capacity. Gases formed by electrolyte decomposition can increase the cell's internal pressure and are a potential safety issue in demanding environments such as mobile devices. Below 25 °C, plating of metallic Lithium on the anodes and subsequent reaction with the electrolyte is leading to loss of cyclable Lithium. Extended storage can trigger an incremental increase in film thickness and capacity loss. Charging at greater than 4.2 V can initiate Li+ plating on the anode, producing irreversible capacity loss. The randomness of the metallic lithium embedded in the anode during intercalation results in dendrites formation. Over time the dendrites can accumulate and pierce the separator, causing a short circuit leading to heat, fire or explosion. This process is referred to as thermal runaway. Discharging beyond 2 V can also result in capacity loss. The (copper) anode current collector can dissolve into the electrolyte. When charged, copper ions can reduce on the anode as metallic copper. Over time, copper dendrites can form and cause a short in the same manner as lithium. High cycling rates and state of charge induces mechanical strain on the anode's graphite lattice. Mechanical strain caused by intercalation and de-intercalation creates fissures and splits of the graphite particles, changing their orientation. This orientation change results in capacity loss. Electrolyte degradation mechanisms include hydrolysis and thermal decomposition. At concentrations as low as 10 ppm, water begins catalyzing a host of degradation products that can affect the electrolyte, anode and cathode. participates in an equilibrium reaction with LiF and . Under typical conditions, the equilibrium lies far to the left. However the presence of water generates substantial LiF, an insoluble, electrically insulating product. LiF binds to the anode surface, increasing film thickness. hydrolysis yields , a strong Lewis acid that reacts with electron-rich species, such as water. reacts with water to form hydrofluoric acid (HF) and phosphorus oxyfluoride. Phosphorus oxyfluoride in turn reacts to form additional HF and difluorohydroxy phosphoric acid. HF converts the rigid SEI film into a fragile one. On the cathode, the carbonate solvent can then diffuse onto the cathode oxide over time, releasing heat and potentially causing thermal runaway. Decomposition of electrolyte salts and interactions between the salts and solvent start at as low as 70 °C. Significant decomposition occurs at higher temperatures. At 85 °C transesterification products, such as dimethyl-2,5-dioxahexane carboxylate (DMDOHC) are formed from EC reacting with DMC. Cathode degradation mechanisms include manganese dissolution, electrolyte oxidation and structural disorder. In hydrofluoric acid catalyzes the loss of metallic manganese through disproportionation of trivalent manganese: 2Mn3+ → Mn2++ Mn4+ Material loss of the spinel results in capacity fade. Temperatures as low as 50 °C initiate Mn2+ deposition on the anode as metallic manganese with the same effects as lithium and copper plating. Cycling over the theoretical max and min voltage plateaus destroys the crystal lattice via Jahn-Teller distortion, which occurs when Mn4+ is reduced to Mn3+ during discharge. Storage of a battery charged to greater than 3.6 V initiates electrolyte oxidation by the cathode and induces SEI layer formation on the cathode. As with the anode, excessive SEI formation forms an insulator resulting in capacity fade and uneven current distribution. Storage at less than 2 V results in the slow degradation of and cathodes, the release of oxygen and irreversible capacity loss. The need to "condition" NiCd and NiMH batteries has leaked into folklore surrounding Li-ion batteries, but is unfounded. The recommendation for the older technologies is to leave the device plugged in for seven or eight hours, even if fully charged. This may be a confusion of battery software calibration instructions with the "conditioning" instructions for NiCd and NiMH batteries. Safety Fire hazard Lithium-ion batteries can be a safety hazard since they contain a flammable electrolyte and may become pressurized if they become damaged. A battery cell charged too quickly could cause a short circuit, leading to explosions and fires. A Li-ion battery fire can be started due to (1) thermal abuse, e.g. poor cooling or external fire, (2) electrical abuse, e.g. overcharge or external short circuit, (3) mechanical abuse, e.g. penetration or crash, or (4) internal short circuit, e.g. due to manufacturing flaws or aging. Because of these risks, testing standards are more stringent than those for acid-electrolyte batteries, requiring both a broader range of test conditions and additional battery-specific tests, and there are shipping limitations imposed by safety regulators. There have been battery-related recalls by some companies, including the 2016 Samsung Galaxy Note 7 recall for battery fires. Lithium-ion batteries have a flammable liquid electrolyte. A faulty battery can cause a serious fire. Faulty chargers can affect the safety of the battery because they can destroy the battery's protection circuit. While charging at temperatures below 0 °C, the negative electrode of the cells gets plated with pure lithium, which can compromise the safety of the whole pack. Short-circuiting a battery will cause the cell to overheat and possibly to catch fire. Smoke from thermal runaway in a Li-ion battery is both flammable and toxic. The fire energy content (electrical + chemical) of cobalt-oxide cells is about 100 to 150 kJ/(A·h), most of it chemical. Around 2010, large lithium-ion batteries were introduced in place of other chemistries to power systems on some aircraft; , there had been at least four serious lithium-ion battery fires, or smoke, on the Boeing 787 passenger aircraft, introduced in 2011, which did not cause crashes but had the potential to do so. UPS Airlines Flight 6 crashed in Dubai after its payload of batteries spontaneously ignited. To reduce fire hazards, research projects are intended to develop non-flammable electrolytes. Damaging and overloading If a lithium-ion battery is damaged, crushed, or is subjected to a higher electrical load without having overcharge protection, then problems may arise. External short circuit can trigger the battery explosion. If overheated or overcharged, Li-ion batteries may suffer thermal runaway and cell rupture. In extreme cases this can lead to leakage, explosion or fire. To reduce these risks, many lithium-ion cells (and battery packs) contain fail-safe circuitry that disconnects the battery when its voltage is outside the safe range of 3–4.2 V per cell. or when overcharged or discharged. Lithium battery packs, whether constructed by a vendor or the end-user, without effective battery management circuits are susceptible to these issues. Poorly designed or implemented battery management circuits also may cause problems; it is difficult to be certain that any particular battery management circuitry is properly implemented. Voltage limits Lithium-ion cells are susceptible to stress by voltage ranges outside of safe ones between 2.5 and 3.65/4.1/4.2 or 4.35V (depending on the components of the cell). Exceeding this voltage range results in premature aging and in safety risks due to the reactive components in the cells. When stored for long periods the small current draw of the protection circuitry may drain the battery below its shutoff voltage; normal chargers may then be useless since the battery management system (BMS) may retain a record of this battery (or charger) 'failure'. Many types of lithium-ion cells cannot be charged safely below 0 °C, as this can result in plating of lithium on the anode of the cell, which may cause complications such as internal short-circuit paths. Other safety features are required in each cell: Shut-down separator (for overheating) Tear-away tab (for internal pressure relief) Vent (pressure relief in case of severe outgassing) Thermal interrupt (overcurrent/overcharging/environmental exposure) These features are required because the negative electrode produces heat during use, while the positive electrode may produce oxygen. However, these additional devices occupy space inside the cells, add points of failure, and may irreversibly disable the cell when activated. Further, these features increase costs compared to nickel metal hydride batteries, which require only a hydrogen/oxygen recombination device and a back-up pressure valve. Contaminants inside the cells can defeat these safety devices. Also, these features can not be applied to all kinds of cells, e.g., prismatic high current cells cannot be equipped with a vent or thermal interrupt. High current cells must not produce excessive heat or oxygen, lest there be a failure, possibly violent. Instead, they must be equipped with internal thermal fuses which act before the anode and cathode reach their thermal limits. Replacing the lithium cobalt oxide positive electrode material in lithium-ion batteries with a lithium metal phosphate such as lithium iron phosphate (LFP) improves cycle counts, shelf life and safety, but lowers capacity. As of 2006, these 'safer' lithium-ion batteries were mainly used in electric cars and other large-capacity battery applications, where safety is critical. Recalls In October 2004, Kyocera Wireless recalled approximately 1 million mobile phone batteries to identify counterfeits. In December 2005, Dell recalled approximately 22,000 laptop computer batteries, and 4.1 million in August 2006. In 2006, approximately 10 million Sony batteries used in Dell, Sony, Apple, Lenovo, Panasonic, Toshiba, Hitachi, Fujitsu and Sharp laptops were recalled. The batteries were found to be susceptible to internal contamination by metal particles during manufacture. Under some circumstances, these particles could pierce the separator, causing a dangerous short circuit. In March 2007, computer manufacturer Lenovo recalled approximately 205,000 batteries at risk of explosion. In August 2007, mobile phone manufacturer Nokia recalled over 46 million batteries at risk of overheating and exploding. One such incident occurred in the Philippines involving a Nokia N91, which used the BL-5C battery. In September 2016, Samsung recalled approximately 2.5 million Galaxy Note 7 phones after 35 confirmed fires. The recall was due to a manufacturing design fault in Samsung's batteries which caused internal positive and negative poles to touch. Transport restrictions IATA estimates that over a billion lithium and lithium-ion cells are flown each year. Some kinds of lithium batteries may be prohibited aboard aircraft because of the fire hazard. Some postal administrations restrict air shipping (including EMS) of lithium and lithium-ion batteries, either separately or installed in equipment. Environmental impact Extraction of lithium, nickel, and cobalt, manufacture of solvents, and mining byproducts present significant environmental and health hazards. Lithium extraction can be fatal to aquatic life due to water pollution. It is known to cause surface water contamination, drinking water contamination, respiratory problems, ecosystem degradation and landscape damage. It also leads to unsustainable water consumption in arid regions (1.9 million liters per ton of lithium). Massive byproduct generation of lithium extraction also presents unsolved problems, such as large amounts of magnesium and lime waste. Lithium mining takes place in North and South America, Asia, South Africa, Australia, and China. Cobalt for Li-ion batteries is largely mined in the Congo (see also Mining industry of the Democratic Republic of the Congo) Manufacturing a kg of Li-ion battery takes about 67 megajoule (MJ) of energy. The global warming potential of lithium-ion batteries manufacturing strongly depends on the energy source used in mining and manufacturing operations, and is difficult to estimate, but one 2019 study estimated 73 kg CO2e/kWh. Effective recycling can reduce the carbon footprint of the production significantly. Solid waste and recycling Since Li-ion batteries contain less toxic metals than other types of batteries which may contain lead or cadmium, they are generally categorized as non-hazardous waste. Li-ion battery elements including iron, copper, nickel and cobalt are considered safe for incinerators and landfills. These metals can be recycled, usually by burning away the other materials, but mining generally remains cheaper than recycling; recycling may cost $3/kg, and in 2019 less than 5% of lithium ion batteries were being recycled. Since 2018, the recycling yield was increased significantly, and recovering lithium, manganese, aluminum, the organic solvents of the electrolyte, and graphite is possible at industrial scales. The most expensive metal involved in the construction of the cell is cobalt. Lithium is less expensive than other metals used and is rarely recycled, but recycling could prevent a future shortage. Accumulation of battery waste presents technical challenges and health hazards. Since the environmental impact of electric cars is heavily affected by the production of lithium-ion batteries, the development of efficient ways to repurpose waste is crucial. Recycling is a multi-step process, starting with the storage of batteries before disposal, followed by manual testing, disassembling, and finally the chemical separation of battery components. Re-use of the battery is preferred over complete recycling as there is less embodied energy in the process. As these batteries are a lot more reactive than classical vehicle waste like tire rubber, there are significant risks to stockpiling used batteries. Pyrometallurgical recovery The pyrometallurgical method uses a high-temperature furnace to reduce the components of the metal oxides in the battery to an alloy of Co, Cu, Fe, and Ni. This is the most common and commercially established method of recycling and can be combined with other similar batteries to increase smelting efficiency and improve thermodynamics. The metal current collectors aid the smelting process, allowing whole cells or modules to be melted at once. The product of this method is a collection of metallic alloy, slag, and gas. At high temperatures, the polymers used to hold the battery cells together burn off and the metal alloy can be separated through a hydrometallurgical process into its separate components. The slag can be further refined or used in the cement industry. The process is relatively risk-free and the exothermic reaction from polymer combustion reduces the required input energy. However, in the process, the plastics, electrolytes, and lithium salts will be lost. Hydrometallurgical metals reclamation This method involves the use of aqueous solutions to remove the desired metals from the cathode. The most common reagent is sulfuric acid. Factors that affect the leaching rate include the concentration of the acid, time, temperature, solid-to-liquid-ratio, and reducing agent. It is experimentally proven that H2O2 acts as a reducing agent to speed up the rate of leaching through the reaction: 2LiCoO2(s) + 3H2SO4 + H2O2 → 2CoSO4(aq) + Li2SO4 + 4H2O + O2 Once leached, the metals can be extracted through precipitation reactions controlled by changing the pH level of the solution. Cobalt, the most expensive metal, can then be recovered in the form of sulfate, oxalate, hydroxide, or carbonate. [75] More recently recycling methods experiment with the direct reproduction of the cathode from the leached metals. In these procedures, concentrations of the various leached metals are premeasured to match the target cathode and then the cathodes are directly synthesized. The main issues with this method, however, is that a large volume of solvent is required and the high cost of neutralization. Although it's easy to shred up the battery, mixing the cathode and anode at the beginning complicates the process, so they will also need to be separated. Unfortunately, the current design of batteries makes the process extremely complex and it is difficult to separate the metals in a closed-loop battery system. Shredding and dissolving may occur at different locations. Direct recycling Direct recycling is the removal of the cathode or anode from the electrode, reconditioned, and then reused in a new battery. Mixed metal-oxides can be added to the new electrode with very little change to the crystal morphology. The process generally involves the addition of new lithium to replenish the loss of lithium in the cathode due to degradation from cycling. Cathode strips are obtained from the dismantled batteries, then soaked in NMP, and undergo sonication to remove excess deposits. It is treated hydrothermally with a solution containing LiOH/Li2SO4 before annealing. This method is extremely cost-effective for noncobalt-based batteries as the raw materials do not make up the bulk of the cost. Direct recycling avoids the time-consuming and expensive purification steps, which is great for low-cost cathodes such as LiMn2O4 and LiFePO4. For these cheaper cathodes, most of the cost, embedded energy, and carbon footprint is associated with the manufacturing rather than the raw material. It is experimentally shown that direct recycling can reproduce similar properties to pristine graphite. The drawback of the method lies in the condition of the retired battery. In the case where the battery is relatively healthy, direct recycling can cheaply restore its properties. However, for batteries where the state of charge is low, direct recycling may not be worth the investment. The process must also be tailored to the specific cathode composition, and therefore the process must be configured to one type of battery at a time. Lastly, in a time with rapidly developing battery technology, the design of a battery today may no longer be desirable a decade from now, rendering direct recycling ineffective. Human rights impact Extraction of raw materials for lithium ion batteries may present dangers to local people, especially land-based indigenous populations. Cobalt sourced from the Democratic Republic of the Congo is often mined by workers using hand tools with few safety precautions, resulting in frequent injuries and deaths. Pollution from these mines has exposed people to toxic chemicals that health officials believe to cause birth defects and breathing difficulties. Human rights activists have alleged, and investigative journalism reported confirmation, that child labor is used in these mines. A study of relationships between lithium extraction companies and indigenous peoples in Argentina indicated that the state may not have protected indigenous peoples' right to free prior and informed consent, and that extraction companies generally controlled community access to information and set the terms for discussion of the projects and benefit sharing. Development of the Thacker Pass lithium mine in Nevada, USA has met with protests and lawsuits from several indigenous tribes who have said they were not provided free prior and informed consent and that the project threatens cultural and sacred sites. Links between resource extraction and missing and murdered indigenous women have also prompted local communities to express concerns that the project will create risks to indigenous women. Protestors have been occupying the site of the proposed mine since January, 2021. Research Researchers are actively working to improve the power density, safety, cycle durability (battery life), recharge time, cost, flexibility, and other characteristics, as well as research methods and uses, of these batteries. See also Borate oxalate Comparison of commercial battery types European Battery Alliance Gigafactory 1 Lithium as an investment Nanowire battery Solid-state battery Thin film lithium-ion battery References Further reading External links . List of World's Largest Lithium-ion Battery Factories (2020). Energy Storage Safety at National Renewable Energy Laboratory (NREL). New More Efficient Lithium-ion Batteries The New York Times. September 2021. NREL Innovation Improves Safety of Electric Vehicle Batteries, NREL, October 2015. Degradation Mechanisms and Lifetime Prediction for Lithium-Ion Batteries, NREL, July 2015. Impact of Temperature Extremes on Large Format Li-ion Batteries for Vehicle Applications, NREL, March 2013. Japanese inventions 20th-century inventions Metal-ion batteries American inventions English inventions

laptop Battery Life

Advanced Power Management Advanced power management (APM) is an API developed by Intel and Microsoft and released in 1992 which enables an operating system running an IBM-compatible personal computer to work with the BIOS (part of the computer's firmware) to achieve power management. Revision 1.2 was the last version of the APM specification, released in 1996. ACPI is the successor to APM. Microsoft dropped support for APM in Windows Vista. The Linux kernel still mostly supports APM, though support for APM CPU idle was dropped in version 3.0. Overview APM uses a layered approach to manage devices. APM-aware applications (which include device drivers) talk to an OS-specific APM driver. This driver communicates to the APM-aware BIOS, which controls the hardware. There is the ability to opt out of APM control on a device-by-device basis, which can be used if a driver wants to communicate directly with a hardware device. Communication occurs both ways; power management events are sent from the BIOS to the APM driver, and the APM driver sends information and requests to the BIOS via function calls. In this way the APM driver is an intermediary between the BIOS and the operating system. Power management happens in two ways; through the above-mentioned function calls from the APM driver to the BIOS requesting power state changes, and automatically based on device activity. In APM 1.0 and APM 1.1, power management is almost fully controlled by the BIOS. In APM 1.2, the operating system can control PM time (e.g. suspend timeout). Power management events There are 12 power events (such as standby, suspend and resume requests, and low battery notifications), plus OEM-defined events, that can be sent from the APM BIOS to the operating system. The APM driver regularly polls for event change notifications. Power Management Events: APM functions There are 21 APM function calls defined that the APM driver can use to query power management statuses, or request power state transitions. Example function calls include letting the BIOS know about current CPU usage (the BIOS may respond to such a call by placing the CPU in a low-power state, or returning it to its full-power state), retrieving the current power state of a device, or requesting a power state change. Power states The APM specification defines system power states and device power states. System power states APM defines five power states for the computer system: Full On: The computer is powered on, and no devices are in a power saving mode. APM Enabled: The computer is powered on, and APM is controlling device power management as needed. APM Standby: Most devices are in their low-power state, the CPU is slowed or stopped, and the system state is saved. The computer can be returned to its former state quickly (in response to activity such as the user pressing a key on the keyboard). APM Suspend: Most devices are powered off, but the system state is saved. The computer can be returned to its former state, but takes a relatively long time. (Hibernation is a special form of the APM Suspend state). Off: The computer is turned off. Device power states APM also defines power states that APM-aware hardware can implement. There is no requirement that an APM-aware device implement all states. The four states are: Device On: The device is in full power mode. Device Power Managed: The device is still powered on, but some functions may not be available, or may have reduced performance. Device Low Power: The device is not working. Power is maintained so that the device may be 'woken up'. Device Off: The device is powered off. CPU The CPU core (defined in APM as the CPU clock, cache, system bus and system timers) is treated specially in APM, as it is the last device to be powered down, and the first device to be powered back up. The CPU core is always controlled through the APM BIOS (there is no option to control it through a driver). Drivers can use APM function calls to notify the BIOS about CPU usage, but it is up to the BIOS to act on this information; a driver cannot directly tell the CPU to go into a power saving state. In ATA drives The ATA specification defines APM provisions for hard drives via the subcommand , which specifies a trade-off between spin-down frequency and always-on performance. Unlike the BIOS-side APM, the ATA APM has never been deprecated. Aggressive spin-down frequencies may reduce drive lifespan by unnecessarily accumulating load cycles; most modern drives are specified to sustain 300,000 cycles and usually last at least 600,000. On the other hand, not spinning down the drive will cause extra power draw and heat generation; high temperatures also reduce the lifespan of hard drives. See also Active State Power Management - hardware power management protocol for PCI Express Advanced Configuration and Power Interface (ACPI) - successor to APM Green computing Power management BatteryMAX (idle detection) References External links APM V1.2 Specification (RTF file). BIOS

laptop Battery Life

Laptop (disambiguation) A laptop is a personal computer for mobile use. Laptop may also refer to: Laptop (2008 film), a 2008 Malayalam film Laptop (2012 film), a 2012 Bengali film Laptop (band), an American band with Jesse Hartman See also

laptop Battery Life

Batteroo Boost The Batteroo Boost (formerly known as the Batteriser ( )) is a line of products designed by Batteroo, Inc. that is claimed to significantly extend battery life by using a miniature boost voltage regulator. It was crowd-funded on Indiegogo. The company is based in Sunnyvale, California and founded by Bob Roohparvar and Frankie Roohparvar. Product details A patent was filed by Fariborz Frankie Roohparvar with the priority date of September 20, 2010. The Batteroo Boost is claimed to extend the life of both new and used batteries. Batteroo has said that Batterisers are non-toxic, reusable, and coated with a non-conductive coating to prevent any risk of shorts. They also claim that a built-in reverse polarity protection mechanism eliminates dangers of inserting a battery into the Batteriser the wrong way. Crowdfunding completed between July 2015 produced $394,459, while the initial goal was $30,000. During the crowdfunding Batteroo announced they would be producing Batteroo Boost for AA, AAA, C, and D batteries. In August 2017, Batteroo launched a second crowd-funding campaign for a line of products for rechargeable batteries called Batteroo Reboost. In this crowd-funding campaign, they raised an additional $42,311. The shipping date for the product has been delayed for various reasons, but photos from the manufacturing process have been made available. As of early May 2016, the company was months overdue to ship to its Indiegogo backers, with some backers accusing Batteroo of running a scam. Product tests In a test by UL, a Garmin Golf GPS using Batteroo Boost was shown to have a lifespan of 10 hours and 12 minutes, in contrast to the 1 hour and 43 minutes of operating time without a Batteroo Boost. However, TechnologyCatalyst attempted to duplicate the test and found that the Garmin operated normally for over 17 hours on ordinary AA batteries, suggesting that the report by UL was based on the sloppy test design. PC World's Jon Phillips demoed the Batteroo Boost operating on batteries in an Apple Inc. keyboard that he claimed were dead. The 'power meter' on the computer's screen showed the batteries as being dead without the Batteroo Boost, and as having 100% power remaining with the Batteriser. Brian Dipert at EDN called into question the strain on the keyboard being caused by the 'power meter,' and suggested that this test might not be representative of the Batteroo Boost's effectiveness in other applications. Controversies Effectiveness The Batteriser's efficacy in consumer applications has been challenged by a number of sources. A source of contention surrounds the brownout voltages for battery-operated devices. David L. Jones in his EEVBlog used a programmable power supply to determine that nearly all devices function in some respect until around 1.1V, or roughly 80% of a battery's life due to the non-linear discharge curve of batteries. This stands in contrast to Batteroo's claim that using a Batteroo Boost will unlock the remaining 80% of power (from 1.3V downwards). Batteroo has claimed that the bench power supply test is flawed, because of the definitions used by Jones to define device functionality, the inherent differences between power supplies and batteries on the basis of Equivalent Series Resistance (ESR), and different measures of voltage (confusion between open circuit voltage and closed circuit voltage). A further source of controversy is that the Batteroo Boost will shorten battery life in devices that undergo only intermittent use, because the Batteriser is always drawing power to boost the voltage, even when the device is idle. The first devices were delivered at the end of 2016. Frank Buss, and later on, Dave Jones, concluded in a first test that the device is not efficient when used in an electronically-unregulated toy train. Potential dangers David Jones on EEV Blog raised the concern that because the Batteroo Boost acts as a ground for the boost converter circuit, any nick in the insulation might result in a direct short, and potentially a fire. Internet controversy In the wake of Dave Jones' video about Batteriser, his video was disliked by an abnormally large amount Youtube accounts with IP addresses located in Vietnam. Other bloggers with Batteroo Boost-related videos experienced similar activity from addresses in Vietnam. The bloggers involved suspect that either a click farm in Vietnam was engaged to disrepute those attacking Batteroo Boost, or a single computer with many fake or stolen YouTube accounts utilized proxied IP addresses to cover its tracks. Lawsuit regarding name On July 25, 2016, Energizer Brands LLC filed a federal lawsuit, saying that the name Batteriser violates a variety of its trademarks on the word "energizer". The lawsuit said that "... despite advertisements, solicitation, and pre-orders, Batteroo has not delivered a single Batteriser product to a consumer in the ordinary course of business." According to the lawsuit, the Trademark Trial and Appeal Board ruled June 27 in favor of Energizer and refused registration of the Batteriser and Batterise marks. According to Energizer, Batteroo also tried to falsely implicate Energizer in the product delays of Batteriser. See also Undervoltage-lockout Joule thief References Electric power conversion Consumer electronics Indiegogo projects

laptop Battery Life

ThinkPad L series The ThinkPad L-series laptops from Lenovo were designed with the theme of "green". The first laptops in the series were described by Lenovo as being the environmentally friendliest products in the ThinkPad range. Key features that contributed to the eco-friendly tag were the use of recycled material for packaging and post-consumer recycled content (such as office water jugs and used IT equipment). The predecessor of the ThinkPad L series was the ThinkPad A series, conceived as a desktop replacement. The ThinkPad A series was discontinued in favor of two product lines, the ThinkPad R series and the ThinkPad G series. The ThinkPad R series introduced Lenovo's new product naming system, as indicated in the published tech specs. The R61 laptop was renamed as R400 and R500. The first digit in the name referred to the display screen size of the product. The R400 laptop had a 14.1" display, while the R500 laptop had a 15.4" display. From the R series onwards, all ThinkPad models transitioned to widescreen displays. Models 2010 The L-series laptops were launched in 2010 to replace the ThinkPad R series. The first two L-series models – the ThinkPad L412 and the ThinkPad L512 laptops – were predicted to be launched on Earth Day in 2010. The L410 and L510 models ships only in a India market. L412 and L512 The L412 and L512 laptops met eight military specifications, including parameters for high and low temperature, vibration, altitude and dust. However, the L-series laptops remained relatively lightweight starting at 5.2 lbs (≈2.36 kg). The L-series models were also reputed to be Lenovo's greenest laptops. Lenovo indicated that they were 40% more power efficient than other laptops, and were made from recycled plastic from office water jugs and miscellaneous used equipment. The L-series laptops were made available with a variety of options, allowing them to be customized to handle business demands, or used as entry-level laptops. The laptops could be equipped with Intel i3 or i5 processors, integrated graphics, or discrete AMD Radeon graphics. Alternatively, the L-series entry-level model included a Celeron P4500 CPU,  GB hard disk, and 1 GB RAM. The L series was designed to improve on the features of the R-series laptops. L-series laptops were reputed to increase performance over the R series by 150% and improve boot and shutdown times on Windows by 57%. The laptop chassis was also 11% thinner and 12% lighter than the R-series models it was introduced to replace. Upon release, the ThinkPad L412 was praised by reviewers, with Laptop Magazine calling it a "value-priced business notebook". The review also praised the laptop for green features, performance, and ergonomic design. The L412 was well received by Laptop Magazine, with the reviewer giving the laptop a score of 4 out of 5 stars. Similarly, NOTEBOOKCHECK gave the ThinkPad L412 laptop a score of 75% (good) from an average of five scores from seven reviews. PCWorld listed the pros of the ThinkPad L412 laptop as being eco-friendly and affordable, while stating that the cons were the loud keyboard and low battery life. The ThinkPad L512 also received positive reviews, with reviewers comparing it with both the ThinkPad T series and the ThinkPad SL series. NotebookReview.com noted that the L512 was almost identical to comparable SL-series laptops in appearance, with "a consumer take on the rugged, business-oriented T-series ThinkPad". The review also indicated that the chassis flex was less than the Edge 15, but more than the T-series laptops. The L512 was praised for its screen protection with no distortion on the LCD despite heavy pressure applied to the cover, and the easy access to internal components. The green features of the L512 also received notice, with Notebook Review stating that "The L series offers up to 30% post-consumer content, LED-backlit screens and green packaging that takes up 20% less space." 14" (L412) The L412 has a 14.0-inch display. 15" (L512) The L512 has a 15.6-inch display. 2011 In February 2011, the ThinkPad L420 and L520 were announced by Lenovo. L420 and L520 Continuing the naming convention, the L420 has a 14" display, while the L520 has a 15" display. The 2011 line of L-series laptops included up to second generation Intel i7 processors, Intel HD Graphics or options for AMD Radeon discrete graphics, Lenovo Enhanced Experience 2.0 for Windows 7, and solid-state storage drives. The L420 and L520 laptops offered battery life of up to 11.5 hours and 10.8 hours respectively with the optional 9-cell battery. Lenovo also indicated that the L-series laptops are lighter than similar, competing products. The L420 and L520 continued the series trend of environmentally friendly features. The L series offered savings on operating costs of 40% annually, as compared to previous generation ThinkPads. The L420 and L520 also featured up to 30% post-consumer recycled content. According to Lenovo, office jugs and used IT equipment had been recycled into different L-series parts including the screen cover, the palm rest, and the top and bottom case. As with most ThinkPad laptops, the L-series models featured certifications from Energy Star and EPEAT Gold. The Laptop Magazine review of the ThinkPad L420 indicated the pros as being the "great keyboard, affordable price, good battery life, and quick boot time". The battery life marked an improvement over the ThinkPad L412, which was criticized for its low battery life. Laptop Magazine indicated that the cons were weak audio, multitouch gestures, and bland design. Other reviews did not raise similar comments about design. For example, Zimbio only indicated that the L420 comes in a "simple, all-black design". However, the audio was criticized by Zimbio as well, with the reviewer indicating that the sound was slightly muffled. The L520 was awarded a Business Buy award from Expert Reviews, which indicated in its review that the laptop would appeal to users who preferred "function over form". The review praised the laptop for performance. Points raised about the display were that the backlight was suitably bright and even, and while colors were clear, they were not as vibrant as those found on a glossy screen. This was suggested by the reviewer to be due to the matte finish on the screen, meant to reduce glare from overhead lighting. The keyboard was lauded, with the reviewers praising the large, molded keys that gave 'great feedback'. The only point of contention was the function key, replacing the Control key at the bottom left corner of the keyboard. 14" (L420) The L420 has a 14.0-inch display. 15" (L520) The L520 has a 15.6-inch display. 2012 In May 2012, the Thinkpad L430 and L530 were announced by Lenovo. L430 and L530 The L430 and L530 replaced the L420 and L520. They have the new, island type keyboard. 14" (L430) The L430 has a 14.0-inch display. 15" (L530) The L530 has a 15.6-inch display. 2013 L440 and L540 Introduced in October 2013, these feature the new 4th-gen Haswell Intel CPUs, and the new press-to-click 5-point touchpad, integrating the trackpoint's buttons with the top of the touchpad. 14" (L440) The L440 has a 14.0-inch display. 15" (L540) The L540 has a 15.6-inch display. 2014 L450 Features the 4th-gen Haswell Intel CPUs and the 5th-gen Broadwell Intel CPUs. 14" (L450) The L450 has a 14.0-inch display. 2016 L460 and L560 Introduced in first quarter 2016, these feature the new 6th-gen Skylake Intel CPUs. 14" (L460) The L460 has a 14.0-inch display. 15" (L560) The L560 has a 15.6-inch display. 2017 L470 and L570 Introduced in first quarter 2017, these feature the new 7th-gen Kabylake Intel CPUs. 14" (L470) The L470 has a 14.0-inch display. 15" (L570) The L570 has a 15.6-inch display. 2018 L380, L380 Yoga, L480, and L580 Introduced in first quarter 2018, these feature Celeron, 7th-gen, or the new 8th-gen Kabylake R (refresh) Intel CPUs. 13" (L380, L380 Yoga) The L380 and L380 Yoga have a 13.3-inch display. The Yoga is convertible. 14" (L480) The L480 has a 14.0-inch display. 15" (L580) The L580 has a 15.6-inch display. 2019 L390, L390 Yoga, L490, and L590 Introduced in first quarter 2019, these feature Celeron or the new 8th-gen Whiskey Lake Intel CPUs. 13" (L390, L390 Yoga) The L390 and L390 Yoga have a 13.3-inch display. The Yoga is convertible. 14" (L490) The L490 has a 14.0-inch display. 15" (L590) The L590 has a 15.6-inch display. 2020 L13, L13 Yoga, L14, and L15 Introduced between the last of quarter 2019 and the beginning of 2020, these feature Celeron, Pentium Gold, the new 10th-gen Intel Core CPUs, or 3rd-gen Ryzen Mobile. 13" (L13, L13 Yoga) The L13 and L13 Yoga have a 13.3-inch display. The Yoga is convertible. 14" (L14) The L14 has a 14.0-inch display. 15" (L15) The L15 has a 15.6-inch display. References External links ThinkPad L series at Lenovo.com Lenovo laptops L series Computer-related introductions in 2010

laptop Battery Life

Samsung N130 The Samsung N130 is a subnotebook/netbook computer designed by Samsung. At the time of its introduction, it was noted for a good keyboard, large 6-cell battery as standard, giving a battery life of up to 7.5 hours a medium 160gb SATA hard disk drive and a release price of 349 USD. Technical overview Processor and memory The Samsung N130 uses a 1.6 GHz Intel Atom N270 processor. The N130 has 1 GB of 200-pin PC2-6400 800MHz DDR2 SDRAM memory as standard. Internally, the N130 has one slot for memory accepting SO-DIMM memory modules up to 2 GB. Display The screen is a non-glossy LED backlit display and measures 10.1 inches diagonally, and has a resolution of 1024×600 pixels. An external VGA out is also included. Keyboard As with earlier models, the 83-key keyboard is 93% of the size of a full-size keyboard, which makes typing quite easy on the netbook. The keyboard is made with Silver Nano (Anti-Bacterial) technology. Storage The standard internal hard drive size is 160 GB. It also includes an SD card slot, supporting MMC, SD and SDHC cards for additional storage as a standard features of this netbook series. Operating systems The N130 is shipped either with Windows XP Home Edition, Windows Vista Business or Windows 7 Starter. Linux (e.g. Ubuntu, Mandriva) distributions are also supported. Colors and configurations The N130 is available in different colors and configurations. Colors include white, black, blue and pink. The configurations may differ in the lack of Bluetooth, e.g. some models in German markets, the fitting of a UMTS/HSDPA module, a weaker battery. The new model N140 is an upgrade of the basic N130 design, with modified touchpad, Bluetooth 2.0+EDR (standard configuration) and improved styling. Criticism Some users noticed a keyboard typing problem because the placement of the Page up, Backspace and Page down keys was considered troublesome. See also Comparison of netbooks References External links N130 official page Samsung N130 - Community Site Netbooks N130

laptop Battery Life

Green Power Usage Effectiveness Green Power Usage Effectiveness (GPUE) is a proposed measurement of both how much sustainable energy a computer data center uses, its carbon footprint per usable kilowatt hour (kWh) and how efficiently it uses its power; specifically, how much of the power is actually used by the computing equipment (in contrast to cooling and other overhead). It is an addition to the power usage effectiveness (PUE) definition and was first proposed by Greenqloud. The Green Grid has developed the Power Usage Effectiveness metric or PUE to measure a data centers' effectiveness of getting power to IT equipment. What the PUE tells in simple terms is how much extra energy is needed for each usable kWh for the IT equipment due to the power going into cooling, power distribution loss etc. and it's a simple formula (in theory): PUE = Total Facility Power/IT Equipment Power The PUE can change depending on where measurements are made, when they are made and the timespan the measurements are made in. Data centers are subtracting factors from their PUE to lower it e.g. district heating. Some of the issues with PUE are being addressed with the PUEx definition. GPUE is a way to "weigh" the PUE to better see which data centers are truly green in the sense that they indirectly cause the least amount of CO2 to be emitted by their use of sustainable or unsustainable energy sources. This new metric GPUE or Green Power Usage Effectiveness is defined as: GPUE = G × PUEx (for inline comparison of data centers) or = G @ PUEx (a better display and for CO2 emission calculations) The "G" is the key factor here and it is a simple calculated value: G = Weighed sum of energy sources and their lifecycle KG CO2/KWh G =Σ( %EnergySource × ( 1 + weight) ) Adding 1 to the weight is to "weigh" (multiply) with the PUE to get a number that is comparable to PUE. The weights taken directly from the "lifecycle CO2/kWh for electricity generation by power source" table above we got from the 2008 Sovacool Study e.g. the weight for unscrubbed coal is e.g. 1.050 (kg of CO2/kWh) while hydroelectric river generation has a weight of 0.013. An unknown energy source or a "mix" will get the same as the maximum value which for now is the same as coal. Example: PUE 1.20, 50/50 Coal/Hydro G = 0.5*(1+1.050) + 0.5*(1+0.013) G = 1.531, GPUEx = 1.84 or 1.531@1.20 Kg CO2 per usable kWh = (G-1) × PUEx = 0.64 kg See also Power usage effectiveness (PUE) Comparisons of life-cycle greenhouse gas emissions Data center infrastructure efficiency Performance per watt Green computing IT energy management References Sustainable technologies Computers and the environment Benchmarks (computing) Energy conservation Electric power

laptop Battery Life

Deep-cycle battery A deep-cycle battery is a battery designed to be regularly deeply discharged using most of its capacity. The term is traditionally mainly used for lead–acid batteries in the same form factor as automotive batteries; and contrasted with starter or 'cranking' automotive batteries designed to deliver only a small part of their capacity in a short, high-current burst for cranking the engine. For lead-acid deep-cycle batteries there is an inverse correlation between the depth of discharge (DOD) of the battery and the number of charge and discharge cycles it can perform; with an average "depth of discharge" of around 50% suggested as the best for storage vs cost. Newer technologies than the traditional lead-acid (such as lithium-ion batteries) are becoming commonplace in smaller sizes in uses such as smartphones and laptops. The new technologies are also beginning to become common in the same form factor as the automotive lead-acid batteries, although at a large price premium. Types of lead-acid deep-cycle battery The structural difference between deep-cycle and cranking lead-acid batteries is in the lead battery plates. Deep cycle battery plates have thicker active plates, with higher-density active paste material and thicker separators. Alloys used for the plates in a deep cycle battery may contain more antimony than that of starting batteries. The thicker battery plates resist corrosion through extended charge and discharge cycles. Deep-cycle lead-acid batteries generally fall into two distinct categories; flooded (FLA) and valve-regulated lead-acid (VRLA), with the VRLA type further subdivided into two types, Absorbed Glass Mat (AGM) and Gel. The reinforcement of absorbed glass mat separators helps to reduce damage caused by spilling and jolting vibrations. Further, flooded deep-cycle batteries can be divided into subcategories of Tubular-plated Opzs or flat plated. The difference generally affects the cycle life and performance of the cell. Flooded The term "flooded" is used because this type of battery contains a quantity of electrolyte fluid so that the plates are completely submerged. The electrolyte level should be above the tops of the plates which serves as a reservoir to make sure that water loss during charging does not lower the level below the plate tops and cause damage. Flooded batteries will decompose some water from the electrolyte during charging, so regular maintenance of flooded batteries requires inspection of electrolyte level and addition of water. Major modes of failure of deep-cycle batteries are loss of the active material due to shedding of the plates, and corrosion of the internal grid that supports active material. The capacity of a deep cycle battery is usually limited by electrolyte capacity and not by the plate mass, to improve life expectancy. New technologies Although still much more expensive than traditional lead-acid, a wide range of rechargeable battery technologies such as lithium-ion are increasingly attractive for many users. Applications Cathodic protection, which might include marine use Other marine use, especially on a sailboat lacking power generation capability, generally smaller vessels Trolling motors for recreational fishing boats Industrial electrically-propelled forklifts and floor sweepers Motorized wheelchairs Off-grid energy storage systems for solar power or wind power, especially in small installations for a single building or motorhome Power for instruments or equipment at remote sites Recreational vehicles Traction batteries to propel vehicles, such as golf carts, and other highway electric vehicles Traffic signals Uninterruptible power supply ('UPS'), usually for computers and associated equipment, but also sump pumps Audio equipment, similarly to a UPS but also in certain 'clean power' devices to supply clean DC power isolated from the public electric supply for inversion to AC to maximize audio signal reproduction Recycling According to the Battery Council International ("BCI") -- a lead-acid battery industry trade group -- the vast majority of deep cycle batteries on the market today are lead acid batteries. BCI says lead acid batteries are recycled 98% by volume, 99.5% by weight. According to BCI, the plastic cases, lead plates, sulfuric acid, solder, and other metals are 100% recovered for reuse. BCI says the only part of a battery that is not recyclable is the paper separators that wrap the plates (due to the acid bath the paper sits in, the fiber length is reduced so far that it cannot be rewoven). BCI says that, industry wide, there is a greater than 98% rate of recovery on all lead acid batteries sold in the United States, resulting in a virtually closed manufacturing cycle. See also Desulfation Electric vehicle battery Gel battery VRLA battery Opzs List of battery types References External links Battery Council International Car and Deep-Cycle Battery FAQ 7.0 Battery types Energy storage

laptop Battery Life

Sony Vaio X series The Vaio X series is a line of high-end ultraportable notebook computers from Sony introduced in September 2009, claiming to be the world's lightest notebook, at 655 grams ((with special lighter battery, standard weight is 780 grams )). It features an 11.1", 16:9, 1366x768 LED-lit LCD screen with built-in webcam, 2GB of DDR2 RAM, a choice of 64, 128 or 256 GB SSD (no hard drive option, SSD choice depends on territory), Intel Atom Z540 1.86 GHz or Z550 2.00 GHz (CPU choice varies by territory), WWAN (HSDPA, UMTS, EDGE and GPRS built-in). The choice of the slower Intel Atom CPU, rather than a Core 2 chip, arguably places the device in the netbook class, however its pricing at over $1000, and other hardware aspects, such as the high resolution screen, Windows 7 on all models, and SSD usage suggest that it is a full notebook. The device features an SD and Memory Stick reader, Bluetooth support, 2 USB ports, and a VGA port. Due to its thickness (thinner than a MacBook Air), the ethernet port is angled, as a square-on port would be taller than the laptop. Users wanting extended battery life can use the included extended battery, which is described as a battery-stand, tilting the laptop at an angle. External links References X Computer-related introductions in 2009

laptop Battery Life

Battery balancing Battery balancing and battery redistribution refer to techniques that improve the available capacity of a battery pack with multiple cells (usually in series) and increase each cell's longevity. A battery balancer or battery regulator is an electrical device in a battery pack that performs battery balancing. Balancers are often found in lithium-ion battery packs for laptop computers, electrical vehicles. etc. Rationale The individual cells in a battery pack naturally have somewhat different capacities, and so, over the course of charge and discharge cycles, may be at a different state of charge (SOC). Variations in capacity are due to manufacturing variances, assembly variances (e.g., cells from one production run mixed with others), cell aging, impurities, or environmental exposure (e.g., some cells may be subject to additional heat from nearby sources like motors, electronics, etc.), and can be exacerbated by the cumulative effect of parasitic loads, such as the cell monitoring circuitry often found in a battery management system (BMS). Balancing a multi-cell pack helps to maximize capacity and service life of the pack by working to maintain equivalent state-of-charge of every cell, to the degree possible given their different capacities, over the widest possible range. Balancing is only necessary for packs that contain more than one cell in series. Parallel cells will naturally balance since they are directly connected to each other, but groups of parallel wired cells, wired in series (parallel-series wiring) must be balanced between cell groups. Implications for safety To prevent undesirable, and often unsafe conditions, the battery management system must monitor the condition of individual cells for operational characteristics such as temperature, voltage, and sometimes current drawn – although the latter is often only measured per-pack rather than per-cell, perhaps with one-shot protection at the cell level against abnormally high current (such as in a short, or other failure condition.) Under normal operation, discharging must stop when any cell first runs out of charge even though other cells may still hold significant charge. Likewise, charging must stop when any cell reaches its maximum safe charging voltage. Failure to do either may cause permanent damage to the cells, or in extreme cases, may drive cells into reverse polarity, cause internal gassing, thermal runaway, or other catastrophic failures. If the cells are not balanced, such that the high and low cutoff are at least aligned with the state of the lowest capacity cell, the energy that can be taken from and returned to the battery will be limited. Lithium ion rechargeable battery cells are rather more sensitive to overcharging, overheating, improper charge levels during storage, and other forms of mistreatment, than most commonly used battery chemistries (e.g. NiMH). The reason is that the various lithium battery chemistries are susceptible to chemical damage (e.g., cathode fouling, molecular breakdown, etc.) by only very slight overvoltages (i.e., millivolts) during charging, or more charging current than the internal chemistry can tolerate at this point in its charge/discharge cycle, and so on. Heat accelerates these unwanted, but so far inescapable, chemical reactions and overheating during charging amplifies those effects. Because lithium chemistries often permit flexible membrane structures, lithium cells can be deployed in flexible though sealed bags, which permits higher packing densities within a battery pack. When a lithium cell is mistreated, some of the breakdown products (usually of electrolyte chemicals or additives) outgas. Such cells will become 'puffy' and are very much on the way to failure. In sealed lithium-ion cylindrical-format batteries, the same outgassing has caused rather large pressures (800+ psi has been reported); such cells can explode if not provided with a pressure relief mechanism. Compounding the danger is that many lithium cell chemistries include hydrocarbon chemicals (the exact nature of which is typically proprietary), and these are flammable. Therefore, in addition to the risk of cell mistreatment potentially causing an explosion, a simple non-explosive leak can cause a fire. Most battery chemistries have less dramatic, and less dangerous, failure modes. The chemicals in most batteries are often toxic to some degree, but are rarely explosive or flammable; many are corrosive, which accounts for advice to avoid leaving batteries inside equipment for long periods as the batteries may leak and damage the equipment. Lead acid batteries are an exception, for charging them generates hydrogen gas, which can explode if exposed to an ignition source (e.g., a lit cigarette ) and such an explosion will spray sulfuric acid in all directions. Since this is corrosive and potentially blinding, this is a particular danger. Technology Balancing can be active or passive. The term battery regulator typically refers only to devices that perform passive balancing. A full BMS might include active balancing as well as temperature monitoring, charging, and other features to maximize the life of a battery pack. Battery balancing can be performed by DC-DC converters, in one of 3 topologies: Cell-to-battery Battery-to-cell Bidirectional Typically, the power handled by each DC-DC converter is a few orders of magnitude lower than the power handled by the battery pack as a whole. Passive balancing In passive balancing, energy is drawn from the most charged cell and dissipated as heat, usually through resistors. Passive balancing equalizes the state of charge at some fixed point – usually either "top balanced", with all cells reaching 100% SOC at the same time; or "bottom balanced", with all cells reaching minimum SOC at the same time. This can be accomplished by bleeding energy from the cells with higher state of charge (e.g., a controlled short through a resistor or transistor), or shunting energy through a path in parallel with a cell during the charge cycle so that less of the (typically regulated constant) current is consumed by the cell. Passive balancing is inherently wasteful, with some of the pack's energy spent as heat for the sake of equalizing the state of charge between cells. The build-up of waste heat may also limit the rate at which balancing can occur. Active balancing In active balancing, energy is drawn from the most charged cell and transferred to the least charged cells, usually through capacitor-based, inductor-based or DC-DC converters. Active balancing attempts to redistribute energy from cells at full charge to those with a lower state of charge. Energy can be bled from a cell at higher SOC by switching a reservoir capacitor in-circuit with the cell, then disconnecting the capacitor and reconnecting it to a cell with lower SOC, or through a DC-to-DC converter connected across the entire pack. Due to inefficiencies, some energy is still wasted as heat, but not to the same degree. Despite the obvious advantages, the additional cost and complexity of an active balancing topology can be substantial, and doesn't always make sense depending on the application. Another variant sometimes used on EAPC battery packs uses a multi pin connector with a resistor and diode in series on each node: as the drops are known the charger then applies either a suitable discharge current or charges the weak cells until they all read the same loaded terminal voltage. This has the advantage of reducing pack weight slightly and lowering parasitic draw, as well as permitting multi-point balancing. See also Battery charger Charge controller Battery management system Milking booster Wear leveling References Further reading Capacitor Based Battery Balancing System Instructions Lithium-Ion Battery Cell-Balancing Algorithm for Battery Management System Based on Real-Time Outlier Detection Patents , E. Julien, Regulating commutator for secondary battery Energy conversion Battery charging Balancing technology

laptop Battery Life

Rechargeable battery A rechargeable battery, storage battery, or secondary cell (formally a type of energy accumulator), is a type of electrical battery which can be charged, discharged into a load, and recharged many times, as opposed to a disposable or primary battery, which is supplied fully charged and discarded after use. It is composed of one or more electrochemical cells. The term "accumulator" is used as it accumulates and stores energy through a reversible electrochemical reaction. Rechargeable batteries are produced in many different shapes and sizes, ranging from button cells to megawatt systems connected to stabilize an electrical distribution network. Several different combinations of electrode materials and electrolytes are used, including lead–acid, zinc–air, nickel–cadmium (NiCd), nickel–metal hydride (NiMH), lithium-ion (Li-ion), lithium iron phosphate (LiFePO4), and lithium-ion polymer (Li-ion polymer). Rechargeable batteries typically initially cost more than disposable batteries, but have a much lower total cost of ownership and environmental impact, as they can be recharged inexpensively many times before they need replacing. Some rechargeable battery types are available in the same sizes and voltages as disposable types, and can be used interchangeably with them. Billions of dollars in research are being invested around the world for improving batteries and industry also focuses on building better batteries. Applications Devices which use rechargeable batteries include automobile starters, portable consumer devices, light vehicles (such as motorized wheelchairs, golf carts, electric bicycles, and electric forklifts), road vehicles (cars, vans, trucks, motorbikes), trains, small airplanes, tools, uninterruptible power supplies, and battery storage power stations. Emerging applications in hybrid internal combustion-battery and electric vehicles drive the technology to reduce cost, weight, and size, and increase lifetime. Older rechargeable batteries self-discharge relatively rapidly, and require charging before first use; some newer low self-discharge NiMH batteries hold their charge for many months, and are typically sold factory-charged to about 70% of their rated capacity. Battery storage power stations use rechargeable batteries for load-leveling (storing electric energy at times of low demand for use during peak periods) and for renewable energy uses (such as storing power generated from photovoltaic arrays during the day to be used at night). Load-leveling reduces the maximum power which a plant must be able to generate, reducing capital cost and the need for peaking power plants. According to a report from Research and Markets, the analysts forecast the global rechargeable battery market to grow at a CAGR of 8.32% during the period 2018–2022. Small rechargeable batteries can power portable electronic devices, power tools, appliances, and so on. Heavy-duty batteries power electric vehicles, ranging from scooters to locomotives and ships. They are used in distributed electricity generation and in stand-alone power systems. Charging and discharging During charging, the positive active material is oxidized, producing electrons, and the negative material is reduced, consuming electrons. These electrons constitute the current flow in the external circuit. The electrolyte may serve as a simple buffer for internal ion flow between the electrodes, as in lithium-ion and nickel-cadmium cells, or it may be an active participant in the electrochemical reaction, as in lead–acid cells. The energy used to charge rechargeable batteries usually comes from a battery charger using AC mains electricity, although some are equipped to use a vehicle's 12-volt DC power outlet. The voltage of the source must be higher than that of the battery to force current to flow into it, but not too much higher or the battery may be damaged. Chargers take from a few minutes to several hours to charge a battery. Slow "dumb" chargers without voltage or temperature-sensing capabilities will charge at a low rate, typically taking 14 hours or more to reach a full charge. Rapid chargers can typically charge cells in two to five hours, depending on the model, with the fastest taking as little as fifteen minutes. Fast chargers must have multiple ways of detecting when a cell reaches full charge (change in terminal voltage, temperature, etc.) to stop charging before harmful overcharging or overheating occurs. The fastest chargers often incorporate cooling fans to keep the cells from overheating. Battery packs intended for rapid charging may include a temperature sensor that the charger uses to protect the pack; the sensor will have one or more additional electrical contacts. Different battery chemistries require different charging schemes. For example, some battery types can be safely recharged from a constant voltage source. Other types need to be charged with a regulated current source that tapers as the battery reaches fully charged voltage. Charging a battery incorrectly can damage a battery; in extreme cases, batteries can overheat, catch fire, or explosively vent their contents. Rate of discharge Battery charging and discharging rates are often discussed by referencing a "C" rate of current. The C rate is that which would theoretically fully charge or discharge the battery in one hour. For example, trickle charging might be performed at C/20 (or a "20-hour" rate), while typical charging and discharging may occur at C/2 (two hours for full capacity). The available capacity of electrochemical cells varies depending on the discharge rate. Some energy is lost in the internal resistance of cell components (plates, electrolyte, interconnections), and the rate of discharge is limited by the speed at which chemicals in the cell can move about. For lead-acid cells, the relationship between time and discharge rate is described by Peukert's law; a lead-acid cell that can no longer sustain a usable terminal voltage at a high current may still have usable capacity, if discharged at a much lower rate. Data sheets for rechargeable cells often list the discharge capacity on 8-hour or 20-hour or other stated time; cells for uninterruptible power supply systems may be rated at 15-minute discharge. The terminal voltage of the battery is not constant during charging and discharging. Some types have relatively constant voltage during discharge over much of their capacity. Non-rechargeable alkaline and zinc–carbon cells output 1.5V when new, but this voltage drops with use. Most NiMH AA and AAA cells are rated at 1.2 V, but have a flatter discharge curve than alkalines and can usually be used in equipment designed to use alkaline batteries. Battery manufacturers' technical notes often refer to voltage per cell (VPC) for the individual cells that make up the battery. For example, to charge a 12 V lead-acid battery (containing 6 cells of 2 V each) at 2.3 VPC requires a voltage of 13.8 V across the battery's terminals. Damage from cell reversal Subjecting a discharged cell to a current in the direction which tends to discharge it further to the point the positive and negative terminals switch polarity causes a condition called . Generally, pushing current through a discharged cell in this way causes undesirable and irreversible chemical reactions to occur, resulting in permanent damage to the cell. Cell reversal can occur under a number of circumstances, the two most common being: When a battery or cell is connected to a charging circuit the wrong way around. When a battery made of several cells connected in series is deeply discharged. In the latter case, the problem occurs due to the different cells in a battery having slightly different capacities. When one cell reaches discharge level ahead of the rest, the remaining cells will force the current through the discharged cell. Many battery-operated devices have a low-voltage cutoff that prevents deep discharges from occurring that might cause cell reversal. A smart battery has voltage monitoring circuitry built inside. Cell reversal can occur to a weakly charged cell even before it is fully discharged. If the battery drain current is high enough, the cell's internal resistance can create a resistive voltage drop that is greater than the cell's forward emf. This results in the reversal of the cell's polarity while the current is flowing. The higher the required discharge rate of a battery, the better matched the cells should be, both in the type of cell and state of charge, in order to reduce the chances of cell reversal. In some situations, such as when correcting NiCd batteries that have been previously overcharged, it may be desirable to fully discharge a battery. To avoid damage from the cell reversal effect, it is necessary to access each cell separately: each cell is individually discharged by connecting a load clip across the terminals of each cell, thereby avoiding cell reversal. Damage during storage in fully discharged state If a multi-cell battery is fully discharged, it will often be damaged due to the cell reversal effect mentioned above. It is possible however to fully discharge a battery without causing cell reversal—either by discharging each cell separately, or by allowing each cell's internal leakage to dissipate its charge over time. Even if a cell is brought to a fully discharged state without reversal, however, damage may occur over time simply due to remaining in the discharged state. An example of this is the sulfation that occurs in lead-acid batteries that are left sitting on a shelf for long periods. For this reason it is often recommended to charge a battery that is intended to remain in storage, and to maintain its charge level by periodically recharging it. Since damage may also occur if the battery is overcharged, the optimal level of charge during storage is typically around 30% to 70%. Depth of discharge Depth of discharge (DOD) is normally stated as a percentage of the nominal ampere-hour capacity; 0% DOD means no discharge. As the usable capacity of a battery system depends on the rate of discharge and the allowable voltage at the end of discharge, the depth of discharge must be qualified to show the way it is to be measured. Due to variations during manufacture and aging, the DOD for complete discharge can change over time or number of charge cycles. Generally a rechargeable battery system will tolerate more charge/discharge cycles if the DOD is lower on each cycle. Lithium batteries can discharge to about 80 to 90% of their nominal capacity. Lead-acid batteries can discharge to about 50–60%. While flow batteries can discharge 100%. Lifespan and cycle stability If batteries are used repeatedly even without mistreatment, they lose capacity as the number of charge cycles increases, until they are eventually considered to have reached the end of their useful life. Different battery systems have differing mechanisms for wearing out. For example, in lead-acid batteries, not all the active material is restored to the plates on each charge/discharge cycle; eventually enough material is lost that the battery capacity is reduced. In lithium-ion types, especially on deep discharge, some reactive lithium metal can be formed on charging, which is no longer available to participate in the next discharge cycle. Sealed batteries may lose moisture from their liquid electrolyte, especially if overcharged or operated at high temperature. This reduces the cycling life. Recharging time Recharging time is an important parameter to the user of a product powered by rechargeable batteries. Even if the charging power supply provides enough power to operate the device as well as recharge the battery, the device is attached to an external power supply during the charging time. For electric vehicles used industrially, charging during off-shifts may be acceptable. For highway electric vehicles, rapid charging is necessary for charging in a reasonable time. A rechargeable battery cannot be recharged at an arbitrarily high rate. The internal resistance of the battery will produce heat, and excessive temperature rise will damage or destroy a battery. For some types, the maximum charging rate will be limited by the speed at which active material can diffuse through a liquid electrolyte. High charging rates may produce excess gas in a battery, or may result in damaging side reactions that permanently lower the battery capacity. Very roughly, and with many exceptions and caveats, restoring a battery's full capacity in one hour or less is considered fast charging. A battery charger system will include more complex control-circuit- and charging strategies for fast charging, than for a charger designed for slower recharging. Active components The active components in a secondary cell are the chemicals that make up the positive and negative active materials, and the electrolyte. The positive and negative electrodes are made up of different materials, with the positive exhibiting a reduction potential and the negative having an oxidation potential. The sum of the potentials from these half-reactions is the standard cell potential or voltage. In primary cells the positive and negative electrodes are known as the cathode and anode, respectively. Although this convention is sometimes carried through to rechargeable systems—especially with lithium-ion cells, because of their origins in primary lithium cells—this practice can lead to confusion. In rechargeable cells the positive electrode is the cathode on discharge and the anode on charge, and vice versa for the negative electrode. Types Commercial types The lead–acid battery, invented in 1859 by French physicist Gaston Planté, is the oldest type of rechargeable battery. Despite having a very low energy-to-weight ratio and a low energy-to-volume ratio, its ability to supply high surge currents means that the cells have a relatively large power-to-weight ratio. These features, along with the low cost, makes it attractive for use in motor vehicles to provide the high current required by automobile starter motors. The nickel–cadmium battery (NiCd) was invented by Waldemar Jungner of Sweden in 1899. It uses nickel oxide hydroxide and metallic cadmium as electrodes. Cadmium is a toxic element, and was banned for most uses by the European Union in 2004. Nickel–cadmium batteries have been almost completely superseded by nickel–metal hydride (NiMH) batteries. The nickel–iron battery (NiFe) was also developed by Waldemar Jungner in 1899; and commercialized by Thomas Edison in 1901 in the United States for electric vehicles and railway signalling. It is composed of only non-toxic elements, unlike many kinds of batteries that contain toxic mercury, cadmium, or lead. The nickel–metal hydride battery (NiMH) became available in 1989. These are now a common consumer and industrial type. The battery has a hydrogen-absorbing alloy for the negative electrode instead of cadmium. The lithium-ion battery was introduced in the market in 1991, is the choice in most consumer electronics, having the best energy density and a very slow loss of charge when not in use. It does have drawbacks too, particularly the risk of unexpected ignition from the heat generated by the battery. Such incidents are rare and according to experts, they can be minimized "via appropriate design, installation, procedures and layers of safeguards" so the risk is acceptable. Lithium-ion polymer batteries (LiPo) are light in weight, offer slightly higher energy density than Li-ion at slightly higher cost, and can be made in any shape. They are available but have not displaced Li-ion in the market. A primary use is for LiPo batteries is in powering remote-controlled cars, boats and airplanes. LiPo packs are readily available on the consumer market, in various configurations, up to 44.4v, for powering certain R/C vehicles and helicopters or drones. Some test reports warn of the risk of fire when the batteries are not used in accordance with the instructions. Independent reviews of the technology discuss the risk of fire and explosion from Lithium-ion batteries under certain conditions because they use liquid electrolytes. Other experimental types ‡ citations are needed for these parameters Notes a Nominal cell voltage in V. b Energy density = energy/weight or energy/size, given in three different units c Specific power = power/weight in W/kg e Energy/consumer price in W·h/US$ (approximately) f Self-discharge rate in %/month g Cycle durability in number of cycles h Time durability in years i VRLA or recombinant includes gel batteries and absorbed glass mats p Pilot production The lithium–sulfur battery was developed by Sion Power in 1994. The company claims superior energy density to other lithium technologies. The thin-film battery (TFB) is a refinement of lithium ion technology by Excellatron. The developers claim a large increase in recharge cycles to around 40,000 and higher charge and discharge rates, at least 5 C charge rate. Sustained 60 C discharge and 1000C peak discharge rate and a significant increase in specific energy, and energy density. Lithium iron phosphate battery is used in some applications. UltraBattery, a hybrid lead–acid battery and ultracapacitor invented by Australia's national science organisation CSIRO, exhibits tens of thousands of partial state of charge cycles and has outperformed traditional lead-acid, lithium and NiMH-based cells when compared in testing in this mode against variability management power profiles. UltraBattery has kW and MW-scale installations in place in Australia, Japan and the U.S.A. It has also been subjected to extensive testing in hybrid electric vehicles and has been shown to last more than 100,000 vehicle miles in on-road commercial testing in a courier vehicle. The technology is claimed to have a lifetime of 7 to 10 times that of conventional lead-acid batteries in high rate partial state-of-charge use, with safety and environmental benefits claimed over competitors like lithium-ion. Its manufacturer suggests an almost 100% recycling rate is already in place for the product. The potassium-ion battery delivers around a million cycles, due to the extraordinary electrochemical stability of potassium insertion/extraction materials such as Prussian blue. The sodium-ion battery is meant for stationary storage and competes with lead–acid batteries. It aims at a low total cost of ownership per kWh of storage. This is achieved by a long and stable lifetime. The effective number of cycles is above 5000 and the battery is not damaged by deep discharge. The energy density is rather low, somewhat lower than lead–acid. Alternatives A rechargeable battery is only one of several types of rechargeable energy storage systems. Several alternatives to rechargeable batteries exist or are under development. For uses such as portable radios, rechargeable batteries may be replaced by clockwork mechanisms which are wound up by hand, driving dynamos, although this system may be used to charge a battery rather than to operate the radio directly. Flashlights may be driven by a dynamo directly. For transportation, uninterruptible power supply systems and laboratories, flywheel energy storage systems store energy in a spinning rotor for conversion to electric power when needed; such systems may be used to provide large pulses of power that would otherwise be objectionable on a common electrical grid. Ultracapacitors capacitors of extremely high value are also used; an electric screwdriver which charges in 90 seconds and will drive about half as many screws as a device using a rechargeable battery was introduced in 2007, and similar flashlights have been produced. In keeping with the concept of ultracapacitors, betavoltaic batteries may be utilized as a method of providing a trickle-charge to a secondary battery, greatly extending the life and energy capacity of the battery system being employed; this type of arrangement is often referred to as a "hybrid betavoltaic power source" by those in the industry. Ultracapacitors are being developed for transportation, using a large capacitor to store energy instead of the rechargeable battery banks used in hybrid vehicles. One drawback of capacitors compared to batteries is that the terminal voltage drops rapidly; a capacitor that has 25% of its initial energy left in it will have one-half of its initial voltage. By contrast, battery systems tend to have a terminal voltage that does not decline rapidly until nearly exhausted. This terminal voltage drop complicates the design of power electronics for use with ultracapacitors. However, there are potential benefits in cycle efficiency, lifetime, and weight compared with rechargeable systems. China started using ultracapacitors on two commercial bus routes in 2006; one of them is route 11 in Shanghai. Flow batteries, used for specialized applications, are recharged by replacing the electrolyte liquid. A flow battery can be considered to be a type of rechargeable fuel cell. Research Rechargeable battery research includes development of new electrochemical systems as well as improving the life span and capacity of current types. See also Battery pack Comparison of commercial battery types Energy density Energy storage List of battery types Metal–air electrochemical cell Search for the Super Battery References Further reading Belli, Brita. ‘Battery University’ Aims to Train a Work Force for Next-Generation Energy Storage, The New York Times, 8 April 2013. Discusses a professional development program at San Jose State University. Vlasic, Bill. Chinese Firm Wins Bid for Auto Battery Maker, The New York Times, published online 9 December 2012, p. B1. Cardwell, Diane. Battery Seen as Way to Cut Heat-Related Power Losses, 16 July 2013 online and 17 July 2013 in print on 17 July 2013, on page B1 in the New York City edition of The New York Times, p. B1. Discusses Eos Energy Systems' Zinc–air batteries. Cardwell, Diane. SolarCity to Use Batteries From Tesla for Energy Storage, 4 December 2013 on line, and 5 December 2013 in the New York City edition of The New York Times, p. B-2. Discusses SolarCity, DemandLogic and Tesla Motors. Galbraith, Kate. In Presidio, a Grasp at the Holy Grail of Energy Storage, The New York Times, 6 November 2010. Galbraith, Kate. Filling the Gaps in the Flow of Renewable Energy, The New York Times, 22 October 2013. Witkin, Jim. Building Better Batteries for Electric Cars, The New York Times, 31 March 2011, p. F4. Published online 30 March 2011. Discusses rechargeable batteries and the new-technology lithium ion battery. Wald, Matthew L. Hold That Megawatt!, The New York Times, 7 January 2011. Discusses AES Energy Storage. Wald, Matthew L. Green Blog: Is That Onions You Smell? Or Battery Juice?, The New York Times, 9 May 2012. Discusses vanadium redox battery technology. Wald, Matthew L. Green Blog: Cutting the Electric Bill with a Giant Battery, The New York Times, 27 June 2012. Discusses Saft Groupe S.A. Wald, Matthew L. Seeking to Start a Silicon Valley for Battery Science, The New York Times, 30 November 2012. Wald, Matthew L. From Harvard, a Cheaper Storage Battery, The New York Times, 8 January 2014. Discusses research into flow-batteries utilizing carbon-based molecules called quinones. Witkin, Jim. Building Better Batteries for Electric Cars, The New York Times, 31 March 2011, p. F4. Published online 30 March 2011. Discusses rechargeable batteries and lithium ion batteries. Witkin, Jim. Green Blog: A Second Life for the Electric Car Battery, The New York Times, 27 April 2011. Describes: ABB; Community Energy Storage for the use of electric vehicle batteries for grid energy storage. Woody, Todd. Green Blog: When It Comes to Car Batteries, Moore’s Law Does Not Compute, The New York Times, 6 September 2010. Discusses lithium-air batteries. Jang Wook Choi. Promise and reality of post-lithium-ion batteries with high energy densities. Flexible electronics

laptop Battery Life

Laptop cooler A laptop/notebook cooler, cooling pad, cooler pad or chill mat is an accessory for laptop computers that helps reduce their operating temperature, which is normally used when the laptop is unable to sufficiently cool itself. Laptop coolers are intended to protect both the laptop from overheating and the user from suffering heat related discomfort. A cooling pad may house active or passive cooling methods and rests beneath the laptop. Active coolers move air or liquid to direct heat away from the laptop quickly, while passive methods may rely on thermally conductive materials or increasing passive airflow. Active coolers Active coolers use small fans to generate additional airflow around the body of the laptop. This helps convect heat away from the device. The number of laptop cooler fans usually range from 1 to 6. Many cooler pads support the use of a power adapter, though they typically run on power drawn through one of the laptop's USB ports. Additionally, many cooler pads come with a built-in USB hub, so as not to consume one of the laptop's often limited number of USB ports. Some active coolers draw heat from the underside of the computer; others work in the opposite way – by blowing cool air towards the machine. The fan speed is adjusted manually or automatically on certain models and on others stays at a fixed speed. Poorly designed coolers may use fans which draw more current than allowed by the USB standard. Without correct protection, such devices can cause damage to the USB power supply. Inside the laptop, the USB power-supply has to output an additional amount of watts for the USB-powered fan, thus generating a small amount of additional heat. This additional heat generation is usually insignificant in relation to the amount of heat a fan moves away from the laptop. Some high-end active coolers have blowers instead of fans, with filters to stop dust from entering the laptop, and have seals between the cooler and laptop surfaces to prevent recirculation of hot air from entering the laptop. Passive coolers Typically, a conductive cooling pad allows for the cooling of a laptop without using any power. These "pads" are normally filled with an organic salt compound that allows them to absorb the heat from the laptop. They are good for a limited amount of time from around 6–8 hours of cooling. Other designs are simply a pad that elevates the laptop so that the fans in the laptop are allowed greater airflow. The conductive cooling pads are not advisable for laptops that have fan vents built into the bottom as the cooling pad blocks the vents leading to overheating or premature system failure. The best way to determine if a cooling pad would be suitable for a particular laptop would be to take a look at the bottom of the laptop and look for air vents or fan vents. If they are on the side and not on the bottom, it is usually safe to use the cooler pad; otherwise, it may not be safe to use a conductive cooler pad. The other variety that can be used simply has a hard resting surface that provides a gap between the cooler and the laptop is normally safer to use. Multi-surface cooler A type of passive cooler that allows both airflow between the laptop base and cooler, as well as, between the base of the cooler and the users's lap. These laptop coolers are well suited to laptops that have vents on its base because it prevents these vents from being blocked regardless of what ever surface the laptop is used on. Therefore, these multi-surface coolers are suitable for use on desk, lap and uneven/soft surfaces (couch, bed/duvet, carpet) and outdoors. Some laptop coolers also feature lights that are activated along with the operation of the cooling fans. They are useful for using the laptop / notebook in low light environments and also serve to decorate the equipment and make it visually interesting. Multipurpose coolers Recent advancements have brought forward coolers that are multipurpose. Features include card readers for various forms of media such as key drives, memory cards, and 2.5" laptop hard disk drives. In addition to the above coolers that are a combination of mini work desk with fans are a convenient addition to users that want to use the laptop on a bed or a couch – although they tend to be too heavy and bulky to be carried conveniently everywhere, limiting mobility. One variant is a cooler with writing pad having an area meant to be used for placing a book or a writing pad – designed with students in mind, although the bigger size limits its mobility and the weight usually results in tired legs for the user when used for a prolonged period of time. A recent addition to the above is an attachable laptop cooler and a comfort pad built into one. References Computer hardware cooling Cooler

laptop Battery Life