How to buy the best rechargeable batteries
Unlike disposable batteries, where you can simply bin a dud pack and vow never to buy them again, buying rechargeable batteries is an investment, as the best types will last for hundreds of hours of use. In fact, our tests have shown that the best AA rechargeable batteries give more than 400 hours of battery life without lasting for a shorter time per charge, live up to their stated capacity and stay charged between uses.
So it's worth doing a little research before you buy, to make sure you get the right ones for your needs.
Duracell, Energizer and Panasonic batteries are among the biggest brands on the market, and all offer more than one type of rechargeable battery. This guide will help you cut through the jargon to find the best rechargeable battery for your gadget - and your budget. Read on to find out what you might want in a rechargeable battery, and we’ll help you avoid spending too much.
How much do I need to spend on rechargeable batteries?
A pack of four rechargeable batteries will cost from around £4 up to £13. You’ll also need a battery charger, so the total cost could be closer to £40. Our tests have revealed that you don’t necessarily need to splash out - we’ve found Best Buy AAA rechargeable batteries costing less than £7 a pack. So our results can save you money as well as show you the best.
Battery offers are worth looking out for if you’re not in a hurry to buy your rechargeable batteries. Keep an eye out in supermarkets and online for the best deals.
What type of rechargeable batteries should I choose?
Nickel-metal hydride (NiMH)
Most rechargeable batteries currently available use nickel-metal hydride chemistry. They are better value than alkaline disposable batteries, especially if you frequently rely on battery power. Our tests found AA rechargeable batteries that will provide more than 400 hours of power to your devices. If your device takes two batteries, the equivalent time using disposables could cost you more than £160.
You might spot nickel zinc (NiZn) rechargeable batteries; we haven’t yet included these in our tests as there are very few available in shops. You shouldn't still be able to find nickel cadmium (NiCad) rechargeable batteries - it's been prohibited to sell these to consumers in the UK since 2006, following EU legislation.
What other features should I look out for?
Capacity in mAh (milliamp hours)
The key feature that differentiates rechargeable batteries of the same size is their capacity, measured in milliamp hours, or mAh. You’ll see this number printed on the packaging, as well as on the battery itself.
Capacity is the amount of electrical charge stored inside the battery. The more charge there is in a battery, the more electrical current it can deliver and the longer it can power your device.
- For AA rechargeable batteries, you’ll find capacities between 1,300mAh and 2,900mAh
- AAA rechargeable batteries range from 500mAh to 1,100mAh.
This doesn’t mean that all batteries with the same mAh value will last the same amount of time in your devices. This is because of different techniques used by manufacturers to make them. Our tests have found batteries with similar stated capacities that last quite different amounts of time.
Some rechargeable batteries are sold with a certain amount of charge already in them, so you can use them in your device straight from the pack. This can be very convenient if you prefer to buy rechargeables, but are out and about and want to use them straight away.
How batteries lose capacity after repeated recharging
Which are the best batteries?
We’ve tested AA and AAA rechargeable batteries from Duracell, Energizer and Panasonic, plus smaller brands, to reveal which are worthy of Best Buy status.
The very best rechargeable batteries balance how long they'll power your devices on a single charge with how well they cope with being used repeatedly. They also live up to their stated capacity and won't leak away their charge when you're not using them. The worst batteries power your devices for noticeably less time when you've used them repeatedly, or lose up to a third of their charge if you don’t use them for seven weeks – so you’d need to be organised to make sure your batteries haven’t gone flat when you need to use them.
Our tough tests have found there’s no direct link between price and performance – so it’s worth doing a bit of research before deciding which rechargeable batteries to buy.