How do I store batteries safely at home?
Keeping terminals apart, the temperature that actually matters, and what to do with a swollen lithium battery.
- Difficulty
- beginner
- Time
- 25 min
- Read
- 5 min
- Safety
- warning
Short answer
Keep batteries in their packaging or a purpose-made case so terminals cannot touch each other or loose metal. Cool and dry, not the fridge. Tape the terminals of used batteries, and never put lithium cells in household or recycling bins.
The risk with stored batteries is not leakage but short circuit — a 9V battery or a loose lithium cell touching keys or coins in a drawer can get hot enough to start a fire.
Safety
What you'll need
- A plastic battery case or the original packaging
- Insulating or masking tape
- A lidded metal tin for used lithium cells
Step by step
- Keep terminals from touching anything.This is the core rule. Loose batteries rolling in a drawer with keys, coins or paperclips can short and heat rapidly. Packaging or a case solves it entirely.
- Pay particular attention to 9V batteries.Both terminals are side by side on the top, so anything metal laid across them shorts the battery directly. Always tape the top of a 9V battery, new or used.
- Store cool and dry.Room temperature in a cupboard is right. Heat shortens life significantly, so not near a radiator, in a car, in a loft or in a conservatory.
- Do not put them in the fridge.An old habit that does more harm than good with modern batteries. Condensation on the terminals causes corrosion, and the benefit is negligible.
- Keep new and used separate.Two clearly marked containers. Mixing them wastes new batteries and leads to part-charged sets being fitted, which is how devices leak.
- Never mix types or ages in a device.Old with new, or alkaline with rechargeable, causes one cell to be driven backwards. That is the mechanism behind most battery leaks in a device.
- Take batteries out of anything unused.A torch or a toy left in a cupboard for a year is how alkaline leakage destroys the contacts. If it will not be used for months, take them out.
- Lock button cells away from children.Swallowed button cells cause severe internal burns within hours and are potentially fatal. Store them well out of reach, and check that devices containing them have a screwed battery compartment.
- Know the emergency response for button cells.Straight to A&E if one may have been swallowed. Do not induce vomiting, do not give anything to eat or drink, and say specifically that it may be a button battery.
- Handle lithium batteries as a special case.Power tool packs, phone and laptop batteries and e-bike or scooter batteries. Store at partial charge, cool, and away from anything flammable. Do not leave them charging overnight or unattended.
- Never charge a swollen or damaged lithium battery.Swelling means internal failure. Stop using it, move it somewhere non-flammable away from the house if it is safe to do so, and take it to a recycling point that accepts damaged cells.
- Tape the terminals before disposal.Used batteries still carry enough charge to short and ignite. Tape over the terminals, which is what stops bin lorry and recycling centre fires.
- Never put batteries in household or kerbside bins.Batteries in general waste are a major and growing cause of fires in refuse vehicles and sorting facilities. Supermarkets and shops selling batteries have collection points, usually free.
- Clean up a leak carefully.Alkaline leakage is caustic. Gloves and eye protection, dab the crust with a cotton bud dipped in vinegar or lemon juice to neutralise it, then dry thoroughly.
- Keep only what you use.Batteries lose charge on the shelf, so a large stock stored for years is mostly waste. A modest quantity of the sizes you actually use is more practical.
Tips
- Tape the terminals of every 9V battery, new or used. Both contacts are adjacent and short across anything metal.
- Not the fridge. Condensation corrodes the terminals and the benefit is negligible on modern batteries.
- A swollen lithium battery is failing. Never charge it, never puncture it, and get it to proper recycling.
Common mistakes
- Keeping loose batteries in a drawer with keys and coins — Contact across the terminals shorts the battery, which heats rapidly and can ignite whatever is around it. This is a documented cause of house fires.
- Putting used batteries in the household bin — They are crushed in the collection vehicle, short out and start fires. Lithium cells in particular burn fiercely and are very hard to extinguish.
If it doesn't work
White crusty deposit in a device
Cause: Alkaline battery leakage — Fix: Gloves and eye protection, neutralise with a little vinegar on a cotton bud, dry thoroughly. Badly corroded contacts may not recover.
Battery hot in storage
Cause: Short circuit across the terminals — Fix: Do not handle it directly if it is very hot. Once cool, separate and tape all terminals and store in a case.
Lithium battery pack swollen
Cause: Internal cell failure — Fix: Stop using it, do not charge it, keep it away from anything flammable, and take it to a recycling point that accepts damaged batteries.
New batteries flat already
Cause: Stored too warm, or too long, or shorted — Fix: Store cool and dry in packaging, and buy smaller quantities more often.
Device leaks batteries repeatedly
Cause: Mixed types or ages, or left unused — Fix: Always replace all cells together with the same type, and remove them from anything stored for months.
Questions people ask
Should batteries be kept in the fridge?
No. It was worth a little with older batteries but modern ones lose very little charge at room temperature, and condensation on the terminals when they come out causes corrosion.
How do I dispose of batteries?
Tape the terminals and take them to a collection point. Any shop selling a reasonable quantity of batteries must provide one, so most supermarkets have a box near the entrance.
What do I do if a child swallows a button battery?
Go to A&E immediately and say it may be a button battery. Do not induce vomiting or give food or drink. They cause serious internal burns within a couple of hours.
How should I store power tool batteries?
Cool, dry, partially charged rather than full or empty, off the tool, and away from anything flammable. Do not charge them unattended or overnight.