Many everyday household electronics still take AA and AAA batteries, including cameras, toys, fairy lights, torches, baby monitors and more. If you use these, you can save a lot of money by choosing to buy rechargeable batteries over disposable ones.
But while rechargeable batteries can represent a cost saving, it's not quite as simple as just switching all your batteries to rechargeables. In some devices, disposable batteries are still the better choice.
The good news is that the most power-hungry devices – those which can see you burning through packs of disposables – are the ones you can save a lot of money on when you buy a good rechargeable battery.
Rechargeable AA and AAA batteries cost more than disposables to buy up front. A four-pack can cost around £10 on average, while a pack of alkaline disposables costs between £3 and £4.
Prices vary significantly, especially from retailer to retailer, and batteries are often on sale. But it's true across the board that rechargeable packs cost more than disposables, usually around double.
A charger can cost cost £10- £20, too, adding to the initial outlay.
But if you use power-hungry high drain devices frequently, you'll quickly find that your costs break even.
When running a couple of energy-hungry devices – say, a set of fairy lights and a remote-controlled toy car – you'll find that rechargeable batteries make their money back (including the cost of the charger and the electricity usage) after about 10 charge cycles.
In the long term, the cost savings really stack up. Each charge of a rechargeable battery lasts as long as a full alkaline disposable battery, so for every recharge, you're saving about £1 you'd otherwise spend on a disposable.
To get the most value out of your rechargeables, you should mainly use them in high- and medium-drain devices.
Examples of high-drain devices, where you can expect around seven hours of charge from continuous use, include:
Medium-drain devices are ones where a battery usually lasts 20-30 hours. These include:
This is because rechargeable AA and AAA batteries are most worthwhile if they regularly need charging.
Rechargeable batteries also self-discharge more quickly than disposable batteries. This means that they lose energy when not in use. For this reason, energy-intensive devices that you use often are the most suited to a set of rechargeable batteries.
For low-drain devices like smoke alarms, clocks and television remotes, where the device uses very little energy and it's mainly inactive, alkaline disposables are generally better.
Alkaline disposable batteries last longer in devices that eek out small bits of energy over hundreds of hours. They're better at rationing small amounts of energy because of the way they're built and their chemistry.
It would simply take too long to get through dozens of rechargeable battery cycles in a low-drain device, by which point, after a couple of years, the battery would have degraded anyway.
If you stockpile batteries, rechargeables aren't the best bet. We generally find that 15-20% of a rechargeable battery's capacity declines over two years in storage.
In comparison, alkaline batteries last 5-10 years in storage, while lithium disposable batteries last between 10 and 20 years.
We don't recommend holding onto any battery for too long, because all batteries self-discharge naturally, although you can minimise this by keeping them in a cool environment.
However, if you buy batteries in bulk and use them slowly over years, disposables fare better.
We've just tested seven new rechargeable batteries. Read our reviews of each to see which are the best and most sustainable to buy.