Batteries How we test batteries
Which? disposable battery tests
To discover which batteries are best for your gadgets, we've tested 32 types of disposable battery, both AA and AAA sizes, and we found that you needn't pay a high price for a powerful performance. Log in now to find out which disposable batteries are Best Buys, or try Which? for £1 to get instant access to our site.
We test 11 samples of each battery to ensure consistency in our results and subject each battery to a variety of load conditions to see how they cope in different ‘drain’ situations. The load conditions within our tests vary between AA and AAA batteries, as their capacities are not directly comparable.
We test using a computer-controlled rig that turns each battery on and off to simulate real-life usage – each battery is allowed to rest between controlled drain cycles, and we measure the total length of time it takes before the battery runs flat.
In previous years, we've tested batteries under medium-drain conditions, which simulate the use of an undemanding device, such as a remote control or a pocket radio. However, we found that virtually all supermarket and big-brand batteries excelled in such test conditions, typically lasting well over 15 or even 20 hours. So we now focus on testing batteries under high and very high-drain conditions.
In Autumn 2010, we changed our testing to better reflect real-life battery usage. Previously we measured only how long batteries took to run down to 0.8V, but now we also include 1V as a cut-off point for when we classify the battery as 'dead'. This is because many modern electronic devices, such as digital cameras and DAB radios, stop working at 1V.
Tough and tougher tests
We test every battery under high-drain and very high-drain conditions.
Our high-drain test is demanding on batteries – equivalent to use in a pocket torch, a battery-powered razor or a radio-controlled toy – and battery lifetime varies between six and nine hours.
Very high-drain tests
Our toughest very high-drain test simulates use in a digital camera with an LCD screen (see the Which? digital camera reviews for Best Buys), and battery life typically drops to around two to four hours.
Looking for the best rechargeable batteries instead? Our online review lists current Best Buys.