AA Batteries

The AA battery (sometimes affectionately called "double-A"), is the most common battery size. Every year, about 200 million are sold in the UK alone!

The AA standard actually refers to the physical dimension of the battery: cylindrical, measuring 1.988" (50mm) in height with a diameter of 0.571" (14.5mm). Amongst battery professionals, the AA battery is also called an R6.
Based on this physical standard, a large number of different AA batteries have actually been developed. They differ in performance, electrical specification, and suitability for various applications.

Zinc-Carbon AA batteries have been available for the longest amount of time. They are least expensive, and work well in low drain applications, such as portable radios or torches. They don't work well when the application requires a lot of electricity quickly, because the chemicals in the battery start deteriorating, with the result of the battery losing power. Low to moderate drain applications allow the battery chemicals to recover, and thus make for a reasonable life-span.

Alkaline AA batteries are the best general purpose AA battery available today. They provide more power then Zinc-Carbon AA batteries, and also work much better at lower temperatures. The cheapest alkaline AA battery comes close to a Zinc-Carbon battery in price, but still exceeds it in performance. A top-of-the-range alkaline AA battery, such as the Duracell Ultra M3 commands a visible premium, but outlasts not just Zinc-Carbon AA batteries, but also several other alkaline AA batteries by multiples.

More recently lithium AA batteries have emerged to power high drain devices, such as digital cameras. They clearly outperform any alkaline AA battery in such demanding electronic applications as digital photography, but this extra performance is also visible in their price.

The most economical and environmentally friendly version of the AA battery is the NiMH rechargeable AA battery. Recharging a set of NiMH AA rechargeables costs only a small percentage of the price of alkaline AA batteries, and when you've used them, you don't have to pile your used batteries into a landfill, you simply recharge them. NiMH AA rechargeables also use less dangerous materials than the previous generation of NiCd rechargeable batteries.

Rechargeable AA batteries are also typically rated at a voltage of 1.2V, rather than the 1.5V nominal voltage of the pre-charged batteries. Because of the difference in chemical process inside the battery however, the rechargeable AA battery can still outperform an alkaline AA battery in many applications.

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