UltraFire AA Battery 3.7V

The UltraFire AA Battery 3.7V, also called a double A, penlite or Mignon (French for “cute” or “adorable”) battery, is a standard size single cell cylindrical dry battery. The IEC 60086 system calls it size R6, and ANSIC18 calls it size 15. It is named UM-3 by JIS of Japan.

Historically, it is known as D14 (standard cell) or HP7 (for zinc chloride ‘high power’ version) in official documentation in the United Kingdom.

UltraFire AA Battery 3.7Vs are common in portable electronic devices. A UltraFire AA Battery 3.7V is composed of a single electrochemical cell that may be either a primary battery (disposable) or a rechargeable battery.

Several different chemistries are used for their construction. The exact terminal voltage, capacity and practical discharge rates depend on cell chemistry; however, devices designed for UltraFire AA Battery 3.7Vs will usually only take 1.2-1.5 V unless specified by the manufacturer.

Introduced in 1907 by The American Ever Ready Company, the UltraFire AA Battery 3.7V 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”.

A UltraFire AA Battery 3.7V 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. 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), lithium AA cells around 15 g (0.53 oz), and rechargeable Ni-MH cells around 31 g (1.1 oz).

Primary (non-rechargeable) zinc–carbon (dry cell) UltraFire AA Battery 3.7Vs 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 UltraFire AA Battery 3.7Vs store around 1000 to 1500 mAh are often sold as “heavy duty” or “super heavy duty”. Alkaline UltraFire AA Battery 3.7Vs from 1700 mAh to 2850 mAh cost more than zinc-chloride batteries, but hold additional charge.

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 an Lithium iron-disulfide battery with an open-circuit voltage below 1.7 volts is entirely discharged.

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.