Batteries

How to choose batteries

• Size. The most common are AA (LR6) and AAA (LR03). A 9V battery (6LR61) powers smoke detectors and meters, while C (LR14) and D (LR20) cells run larger torches and radios.
• Alkaline batteries. A good choice for remotes, clocks, scales and toys — devices that draw little power over a long time.
• NiMH rechargeables. Pay off where batteries drain fast: game controllers, cameras, flashguns and kids' toys. Low self-discharge cells such as Panasonic Eneloop hold their charge even in storage.
• Coin cells. The number gives the size: a CR2032 is 20 mm across and 3.2 mm thick. Used in car keys, scales, watches and computer motherboards. Always pick the same number the device takes.
• Pack size. If you get through a lot of batteries, a larger pack is better value and keeps a spare supply at hand.

Safety and recycling

Keep coin cells out of reach of children — a swallowed battery is life-threatening and needs urgent medical attention. Do not mix old and new or different types of batteries in one device. Remove batteries from devices you will not use for a long time so they do not leak. Never try to recharge ordinary batteries. Used batteries and rechargeables do not belong in household waste — take them to a battery collection box or a waste station.

FAQ

Can a NiMH rechargeable replace an AA battery? In most devices, yes. A rechargeable delivers 1.2 V instead of 1.5 V, so some devices will show a low-battery warning sooner.

Can a CR2025 replace a CR2032? The diameter and voltage are the same, but the CR2025 is thinner and may not hold contact firmly. Use the number the device specifies.

How should batteries be stored? In a cool, dry place in their original packaging, so the terminals do not touch metal objects.

See also chargers, power banks and flashlights.