AA batteries might be cheap and cheerful, but that doesn’t mean they’re all the same. Different manufacturers use alternate chemistries and processes to make the batteries, largely affecting how much power the battery can supply, how long it lasts and how fast it loses energy while not in active use. For some purposes – when you’re powering low-drain devices such as a clock or remote control – the differences aren’t that important, but with high-drain devices like a camera, game controller or anything with a lamp, screen or motor, you could see huge differences in lifespan and reliability.
Today’s disposable batteries break down into three basic types:
Zinc chloride: This used to be the general-purpose battery of choice, but alkaline batteries are now so cheap that you don’t often see them. They’re cheap as chips when bought in bulk and fine for low-drain gadgets such as a remote control, but you’ll go through them quickly on anything more demanding.
Alkaline: The mainstream battery technology for high-drain devices. They’re cheap and very easy to find, and last much longer than the old zinc chloride batteries. Technical advances have also seen the major problems – a short shelf life and a propensity to leak – reduced or even fixed.
Lithium: Lithium batteries work even better than alkalines. They last much longer, have an epic shelf life, don’t discharge as much power when not in use and can cope with extreme temperatures. While normal alkaline AAs struggle below 0°C, lithium batteries will operate down to -40°C. They can also be up to 9g lighter than the equivalent alkaline AA battery, which counts when you have something powered by four AAs. The only negative? They’re significantly more expensive.
Generally speaking, you should go for alkalines for most of your battery needs but opt for lithium's for digital cameras or other high-drain products where you need a reliable high charge for as long as possible.