A torch and a radio are only as good as their batteries. Twenty-two of the 24 national guides we compiled list spare batteries; only Belgium and Portugal leave them out. Here is how to choose them, how many to keep, and how to make sure they work on the day.
Start with your devices
Before buying anything, check what your emergency devices take:
- Torch or head torch (all 24 guides list one)
- Radio (all 24 guides)
- Lantern, if you have one
- Hearing aids: eight guides list spare glasses and hearing-aid batteries
- Smoke alarm, CO alarm and thermometer
Ideally, your torch and radio take the same size, usually AA or AAA, so one stock of spares covers both. If you are buying new devices for your kit, choose them with that in mind.
The three types
| Type | Good | Watch out |
|---|---|---|
| Alkaline | Cheap, sold everywhere | Weaker in the cold; old cells can leak inside devices |
| Lithium (AA, AAA) | Store for years; work in the cold; light | Cost more |
| Rechargeable (NiMH) | Reusable, good value over time | Lose charge in storage; need power to recharge |
Alkaline
Ordinary alkaline batteries are fine for a kit you check regularly. Buy them in date, note the expiry date printed on the pack, and use the oldest in everyday devices as you replace them.
Lithium
Lithium AA and AAA cells store for years and keep working in the cold, which matters in a winter outage, a car or an unheated room. They cost more, but for a kit that may sit untouched for a long time, they are the safest choice.
Rechargeable
Rechargeables make sense if you use them every day and always have a charged set. For a kit, their drawback is that they need power to recharge, which is exactly what you won't have. If you rely on them, charge them at every kit check, and keep a set of lithium or alkaline cells as a backup.
How many?
For two adults over three days, we suggest at least eight AA or AAA batteries. A simple rule: one full spare set for each device, plus one extra set for the device you use most, usually the head torch. If you plan for a week or more, add a set per device for each extra few days of evening use.
Keep the radio in mind: a crank or solar radio needs fewer batteries, and a power bank can top up anything that charges by USB. See our guides to the emergency radio and power banks for a power cut.
Storing batteries
- Keep them in their packaging until use. Loose cells that touch each other, or keys and coins, can short-circuit.
- Somewhere cool and dry, indoors. Avoid hot places such as a car in summer or a shelf above a radiator.
- Next to the devices they belong to, so you find both in the dark.
- Don't mix old and new cells, or different types, in the same device.
- Take alkaline cells out of devices you store for a long time, to prevent leaks. Tape them to the device so they stay together.
Check them twice a year
Pick two dates you will remember, such as when the clocks change. Switch on every torch and the radio, replace weak cells, check the expiry dates on your spares, and recharge any rechargeables. Batteries you take out for the TV remote should be replaced the next time you shop.
Button cells and special sizes
Hearing aids, thermometers and some alarms use button cells or less common sizes. These are easy to forget and hard to find in an emergency. Keep at least one spare pack for each, and put hearing-aid batteries with the person's medication.
Summary
- Match your torch and radio to one battery size.
- Choose lithium for cells that will sit in the kit for a long time.
- Keep at least one spare set per device.
- Store them packaged, cool and dry, and check twice a year.
Our checklist includes batteries, sized for your household and your country's guide.