A Battery

Parts of a battery. The answer to “what is inside a battery?” starts with a breakdown of what makes a battery a battery. Container Steel can that houses the cell’s ingredients to form the cathode, a part of the electrochemical reaction. Cathode A combo of manganese dioxide and carbon, cathodes are the electrodes reduced by the electrochemical reaction. A Guide to Understanding Battery Specifications MIT Electric Vehicle Team, December 2008 A battery is a device that converts chemical energy into electrical energy and vice versa. This summary provides an introduction to the terminology used to describe, classify, and compare batteries for hybrid, plug-in hybrid, and electric vehicles.

AA cells

The AA battery is a standard size single cell cylindrical dry battery. The IEC 60086 system calls it size R6, and ANSI C18 calls it size 15.[1] It is named UM-3 by JIS of Japan.[2] Historically, it is known as D14 (standard cell) or HP7 (for zinc chloride 'high power' version) in official documentation in the United Kingdom.

AA batteries are common in portable electronic devices. An AA battery is composed of a single electrochemical cell that may be either a primary battery (disposable) or a rechargeable battery. Several different chemistries are used in their construction. The exact terminal voltage, capacity and practical discharge rates depend on cell chemistry; however, devices designed for AA cells will usually only take 1.2-1.5 V unless specified by the manufacturer.

Introduced in 1907 by The American Ever Ready Company,[3] the AA battery size was standardized by the American National Standards Institute (ANSI) in 1947, but it had been in use in flashlights and electrical novelties before formal standardization. ANSI and IEC Battery nomenclature gives several designations for cells in this size, depending on cell features and chemistry. Due to their popularity in small flashlights, they are often called 'penlight batteries'.


D, C, AA, AAA, AAAA cells, and a 9-volt battery

An AA cell measures 49.2–50.5 mm (1.94–1.99 in) in length, including the button terminal—and 13.5–14.5 mm (0.53–0.57 in) in diameter. The positive terminal button should be a minimum 1 mm high and a maximum 5.5 mm in diameter, the flat negative terminal should be a minimum diameter of 7 mm.[1] 14500 Lithium Batteries are longer if they feature a protection circuit up to 53 mm.

Alkaline AA cells have a weight of roughly 23 g (0.81 oz),[4] lithium AA cells around 15 g (0.53 oz),[5] and rechargeable Ni-MH cells around 31 g (1.1 oz).[6]

Chemistry and capacity[edit]

Primary cells[edit]

Primary (non-rechargeable) zinc–carbon (dry cell) AA batteries have around 400–900 milliampere hours capacity, with measured capacity highly dependent on test conditions, duty cycle, and cut-off voltage. Zinc–carbon batteries are usually marketed as 'general purpose' batteries. Zinc-chloride batteries store around 1000 to 1500 mAh are often sold as 'heavy duty' or 'super heavy duty'. Alkaline batteries from 1700 mAh to 2850 mAh cost more than zinc-chloride batteries, but hold additional charge. AA size alkaline batteries are termed as LR06 by IEC, and AM-3 by JIS.

Non-rechargeable lithium iron disulfide batteries are manufactured for devices that draw more current, such as digital cameras, where their high cost is offset by longer running time between battery changes and more constant voltage during discharge. The capacity of alkaline batteries is greatly reduced as the discharge current increases, however the capacity of a Li-FeS2 battery is not affected by high discharge currents nearly as much as alkaline batteries. Another advantage of lithium disulfide batteries compared to alkaline batteries is that they are less prone to leak. This is particularly important in expensive equipment, where a leaking alkaline battery can damage the equipment due to the corrosive electrolyte coming into contact with sensitive electronics. Lithium iron disulfide batteries are intended for use in equipment compatible with alkaline zinc batteries. Lithium-iron disulfide batteries can have an open-circuit voltage as high as 1.8 volts but the closed-circuit voltage decreases, making this chemistry compatible with equipment intended for zinc-based batteries. A fresh alkaline zinc battery can have an open-circuit voltage of 1.6 volts, but a Lithium iron-disulfide battery with an open-circuit voltage below 1.7 volts is entirely discharged.[7]

Rechargeable cells[edit]

A solar-powered charger for rechargeable AA batteries
Panasonic Eneloop 1.2 volt NiMHrechargeable batteries in AA and AAA

Rechargeable batteries in the AA size are available in multiple chemistries:nickel–cadmium (NiCd) with a capacity of roughly 600–1000 mAh,[8]nickel–metal hydride (NiMH) in various capacities of 600–2750 mAh[9][10] and lithium-ion.Lithium ion chemistry has a nominal voltage of 3.6–3.7 volts, and are referred to as 14500 Li-ion batteries rather than AA.

NiMH and Lithium Ion AA/14500 cells can supply most of their capacity even when under a high current drain (0.5A and higher), unlike Alkaline and Zinc-chloride('Heavy Duty'/'Super Heavy Duty') cells which drop to a small fraction of their low current capacity before even reaching 1 C.[11][12][13][14]


A variant of the 14500 Li-ion batteries, sold by the Chinese company Kentli as 'Kentli PH5' since 2014, comes with an internal buck converter at the positive electrode to downstep the output voltage from the normal 3.7 V to a very consistent (compared to alkaline, NiCd, or even NiMH cells) 1.5 V AA standard voltage.[15] It exposes the normal 3.7 V Li-ion electrode in a ring around the AA electrode for charging. Its more regular voltage provides better drop-in compatibility for alkaline AA devices, and its lithium-ion chemistry provides a lower self-discharge at 3% per month.[16] It holds a mediocre capacity of 1600 mAh (1.5 V) at 50 mA drain, limited by the low efficiency of the step-down converter.[17]

Nickel-zinc cell (NiZn) AAs are also available, but not widely used.

Battery dimensions chart


ChemistryIEC nameANSI/NEDA nameNominal voltage (V)Capacity under 50 mA constant drain (mAh)Max. energy at nominal voltage and 50 mA drain (Wh)Rechargeable
Li-ion??R15/50145003.60–3.70600-840 (1600 mAh at 1.5V)2.88-2.96Yes


A Battery Shelled

In 2011, AA cells accounted for approximately 60% of alkaline battery sales in the United States. In Japan, 58% of alkaline batteries sold were AA, known in that country as tansan (単三). In Switzerland, AA batteries totaled 55% in both primary and secondary (rechargeable) battery sales.[19][20][21]

See also[edit]


  1. ^ abClassic (LR6) datasheet from energizer.com
  2. ^'What are UM3 Batteries?'. Ask Media Group, LLC. Retrieved March 29, 2020.
  3. ^'About Eveready®'. Eveready. Archived from the original on May 9, 2017. Retrieved August 8, 2017.
  4. ^'Energizer Alkaline AA Battery Specification'(PDF). Product Datasheet. Energizer. Retrieved October 21, 2015.
  5. ^'Energizer Lithium AA Battery Specification'(PDF). Energizer. Retrieved October 21, 2015.
  6. ^'Energizer NiMH AA Battery Specification'(PDF). Energizer. Retrieved October 21, 2015.
  7. ^Lithium Iron Disulfide Handbook and Application Manual, Version LI4.04, Energizer Battery Manufacturing Inc.
  8. ^Bergveld, H; Kruijt, W; Notten, P (February 1999). 'Electronic-network modelling of rechargeable NiCd cells and its application to the design of battery management systems'. Journal of Power Sources. 72 (2): 143–158. doi:10.1016/S0378-7753(98)00188-8.
  9. ^'Panasonic NI-MH Handbook'(PDF). Panasonic Industrial. pp. 22–55. Retrieved 16 January 2020.
  10. ^'2018 Panasonic Catalog'(PDF). Panasonic Batteries. pp. 32–43, 60–62. Retrieved 16 January 2020.
  11. ^'Test of Eneloop AA HR-3UTGB 1900mAh (White)'. lygte-info.dk. Retrieved 2019-02-13.
  12. ^'Test of Keeppower 14500 840mAh (Black) 2014'. lygte-info.dk. Retrieved 2019-02-13.
  13. ^'Test of Duracell Ultra Power AA'. lygte-info.dk. Retrieved 2019-02-13.
  14. ^'Test of Panasonic Super Heavy Duty AA CAN'. lygte-info.dk. Retrieved 2019-02-13.
  15. ^Jason Gin. 'Teardown of Kentli PH5 1.5 V Li-Ion AA battery'. Retrieved April 24, 2018.
  16. ^Jason Gin (2 May 2018). 'Completed: Self-discharge test of Kentli PH5 1.5V Li-ion AA (Part 6)'. Rip It Apart - Jason's electronics blog-thingy.
  17. ^Gin, Jason (17 June 2015). 'Performance analysis/review of Kentli PH5 Li-ion 1.5V AA battery'. Rip It Apart - Jason's electronics blog-thingy.
  18. ^[1].
  19. ^Absatzzahlen 2008 INOBAT 2008 statistics.
  20. ^'LIFE CYCLE IMPACTS OF ALKALINE BATTERIES WITH A FOCUS ON END‐OF‐LIFE'(PDF). 3 March 2016. Archived from the original(PDF) on 3 March 2016.
  21. ^'BAJ Website - Monthly battery sales statistics'. www.baj.or.jp.

External links[edit]

Battery Group Size

  • Media related to AA batteries at Wikimedia Commons
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(Redirected from A battery)
A generic triodevacuum tube circuit showing 'A', 'B' and 'C' batteries

A Battery Size

In the early days of electronics, vacuum tube (called valves in British contexts) devices (such as radios) were powered by batteries. Each battery had a different designation depending on which vacuum tube element it was associated with.

Initially, the only such device was a diode with only a filament(cathode) and a plate(anode). Following the direction of electron flow, these electrodes were identified as 'A' and 'B', respectively and thus the associated batteries were referred to as the 'A' battery and 'B' battery, respectively. Later, when the control grid element was added to create the triode tube, it was logically assigned the letter 'C' and supplied from a 'C' battery. Subsequent addition of further internal elements to improve the performance of the triode did not require an extension to this series of batteries – these elements were either resistively-biased from the existing batteries, connected to ground or to the cathode.

A Battery Is What Type Of Energy

This nomenclature was used primarily within North America. Different battery names were used elsewhere in the English speaking world.

A battery[edit]

A battery shelled
Eveready #742 1½ volt 'A' battery with Fahnestock clip terminals
Eveready #762-S 45 volt 'B' battery with 22½ volt tap screw terminals
Eveready #761 4½ volt 'C' battery with 1½ and 3 volt tap screw terminals

An A battery is any battery used to provide power to the filament of a vacuum tube. It is sometimes colloquially referred to as a 'wet battery'. (A dry cell could be used for the purpose, but the ampere-hour capacity of dry cells was too low at the time to be of practical use in this service.) The term comes from the days of valve (tube) radios when it was common practice to use a dry battery for the plate (anode) voltage and a rechargeable lead/acid 'wet' battery for the filament voltage. (The filaments in vacuum tubes consumed much more current than the anodes, and so the 'A' battery would drain much more rapidly than the 'B' battery; therefore, using a rechargeable 'A' battery in this role reduced the need for battery replacement. In contrast, a non-rechargeable 'B' battery would need to be replaced relatively infrequently.)

A batteries were initially 2 volts, being lead acid accumulators, but with the introduction of all dry battery radios, 1.4 volts became more common. Other voltages can be encountered. For example, 7.5 volt batteries were sometimes used to power a series connected set of 1.4 volt valves (tubes).

In Britain and some other countries, the 'A' battery was known as the 'LT' (low tension) battery if dry, and simply the 'accumulator' if wet.

B battery[edit]

A B battery is any battery used to provide the plate voltage of a vacuum tube. It is sometimes colloquially referred to as a 'dry battery' (although there's no reason why a 'wet' battery of suitable voltage couldn't be utilised for the purpose).

The filament is primarily a heat source and therefore the A battery supplies significant current and rapidly discharges. The B battery experiences comparatively little current draw and retains its stored capacity far longer than an A battery. Early B batteries used with bright emitter tubes were 120 volts, but these quickly became obsolete as they were replaced with examples having voltages of typically 45 volts, 67½ volts, or 90 volts as more efficient tubes became available. Some examples had taps every 22½ volts.

A Battery Fan

Even when the plate voltage rail is fed by a power supply rather than a battery, it is generally referred to as the 'B+' line in American schematics.

Because plate voltages can be as high as 300VDC, multiple B batteries may be connected together in series to additively provide the required operating voltages. The much higher available voltage of B batteries means that they must be handled more carefully than other battery types due to their ability to shock and/or burn the person handling them.

A battery stores what type of energy

In Britain and in some other countries, the 'B' battery was known as the 'HT' (high tension) battery.

C battery[edit]


In electronics, a C battery may refer to any battery used to provide bias to the control grid of a vacuum tube. Until the early 1930s this was common practice in valve (tube) radio sets but was largely superseded by grid leakresistors or voltage dividerbiasing. Because the tube grids drew no current, the C battery provided the bias voltage with no current draw. The battery's life in the radio was essentially its shelf life.

Grid bias batteries are still manufactured today, but not for radio use. They are popular in schools and colleges as a convenient variable voltage source in science classes. The most popular battery is the 9 volt type with taps every 1½ volts that accept banana plugs.

A rare form of 'C' battery was the bias cell, a button-size miniature battery designed to deliver a constant voltage with no current drain. These were briefly popular between 1936 and 1945 as the bias cell was less costly than a resistor/capacitor bias network.[1]

In Britain and in some other countries, the 'C' battery was known as the 'GB' (grid bias) battery.

See also[edit]


  1. ^'The Mallory Bias Cell'(PDF). Retrieved August 2, 2020.CS1 maint: discouraged parameter (link)

External links[edit]

  • Instructions for Operating The Crosley 51 Radio Receiver - examples of usage of A, B, and C batteries in an early radio.
  • 1951 Radio Battery Cross Reference Chart - Radio Retailing
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