AA Batteries - 1.5V versus 1.2V

AA batteries come in two voltages - 1.5V and 1.2V which is more common on rechargeables. Most modern electronic equipment should take into account the lower voltage of rechargeable batteries.

Duracell make a rechargeable AA HR6/NiMH at 1.2V (the prefix HR refers to rechargeable batteries, as compared to LR which are standard alkaline batteries). They last 25 hours in a wireless game controller based on an ANSI Digital Audio test.

Duracell Rechargeables AA-type come in two varieties - 2400mAh which is called Rechargeable Ultra and Rechargeable Plus which is 1300 mAh. The Ultra and Plus are not marked on the batteries themselves, but the mAh are. From a buyer's perspective, the higher the mAh the longer the battery will last. An analogy is the size of a gas tank. A possible way to increase mAh is to increase the strength of the electrolytic solution in the battery. They are made in Japan.

NiMH stands for Nickel metal-hydride and these types of batteries were invented in 1967. The European Union Battery Directive caused NiMH batteries to replace Ni-Cd batteries for portable consumer use. Metal hydrides are metals bonded with hydrogen often in a covalent bond, where atoms share electrons.

What is a CR2032 battery?

The CR2032 is a lithium battery button cell rated at 3 Volts. It is used in watches, wireless doorbells and CMOS batteries.

Battery Sizes

The most commonly available batteries are cylindrical cell batteries.

AA - also known as penlights, are one of the most common types of battery in the marketplace. They were introduced in 1907 and are 5cm (50mm) in height.

AAA - are known as microlights. They are 4.45cm in height and slimmer than the AAs.

C - (aka MN1400) 5cm by 2.6cm (same height as AA but fatter). Comes in a range of varieties e.g. LR14 (alkaline), and R-14 (carbon zinc). Used for medium drain applications.

D - 6cm tall by 3.42cm wide. This was introduced in 1898 as the first flashlight battery.

Some cameras use specialist battery types.