Why this happens
Lithium-ion batteries store a lot of energy, and a damaged, overcharged or faulty cell can go into thermal runaway, releasing toxic smoke and fire that spreads quickly and is hard to put out. Most of the risk is controllable: where you charge, which charger you use, the battery's condition and whether someone is around to notice early.
What you need
Tools
- Smoke alarm (battery-operated or professionally installed)
- Fire extinguisher suitable for general household fires, kept near the exit
- Torch
Materials
- The vehicle's original or manufacturer-approved charger
- Non-combustible surface such as a ceramic tile or concrete floor
- Printed family fire plan
Before you start
- Never charge a battery that is swollen, damaged, wet inside or smells unusual.
- Never use a charger that does not match the battery or one from another vehicle.
- If a battery smokes, hisses or catches fire, leave the area, close the door if safe and call 112; do not try to carry a burning or smoking battery.
- Home wiring, sockets and earthing problems are for a licensed electrician.
Step by step
- 1
Choose where to charge
Charge in a well-ventilated place away from beds, sofas, curtains and stored fuel, ideally on a concrete or tiled floor. Never charge in a staircase, corridor or doorway that is your escape route, because a battery fire there can trap people. A ground-floor parking area or open balcony away from combustibles is usually better than a bedroom.
- 2
Use only the matching charger and a proper socket
Use the charger supplied with the vehicle or one the manufacturer approves for that battery. Plug it directly into a wall socket in good condition, not a loose extension board or multi-plug adapter. If the socket, plug or cable gets warm, looks scorched or the circuit trips, stop and have a licensed electrician check the wiring.
- 3
Fit and test a smoke alarm
Install a smoke alarm on the ceiling near where you charge and another on the escape route, following the alarm's instructions. Test it monthly with the test button and replace its battery as recommended. An early warning gives you time to get everyone out before smoke fills the room.
- 4
Charge when someone is around
Charge while you are awake and at home where possible, and unplug once charging is complete instead of leaving it plugged in for days. Avoid charging immediately after a hard ride when the battery is hot; let it cool first. Check the battery and charger by touch and smell during the first charges after any fall or water exposure.
Tip: Set a phone reminder to unplug when charging should be done.
- 5
Inspect the battery regularly
Look for swelling, cracks, dents, leaks, melted plastic or a sweet or chemical smell. Check the charge port and connectors for discolouration. A battery that has been dropped, submerged or damaged in a crash can fail later. Do not charge any battery with these signs; take it to an authorised service centre.
- 6
Keep an extinguisher and know its limits
Keep a fire extinguisher suitable for household fires near the exit, not next to the battery. It can help with surrounding materials or allow escape, but a lithium battery in thermal runaway may reignite and release toxic gases. The priority is to get people out and call the fire service, not to fight a battery fire yourself.
- 7
Make and practise a fire plan
Agree two ways out of every room, a meeting point outside and who helps children or elderly family members. Make sure everyone knows to call 112 in an emergency and to tell the fire service a lithium battery is involved. Walk through the plan once with the family so it feels familiar.
How to tell it worked
Your battery charges on a non-combustible surface away from escape routes with the matching charger, a tested smoke alarm is in place, and everyone in the home knows the way out and to call 112.
Stop and call a technician if
- The battery swells, cracks, leaks or smells sweet or chemical; stop using it and contact an authorised service centre.
- The charger, plug or socket gets hot, discoloured or trips the circuit; stop charging and have it checked.
- The battery has been submerged in water or damaged in a crash; do not charge it until a service centre has inspected it.
Questions
Is it safe to charge overnight?
It is safer to charge while you are awake and unplug when done. If you must charge overnight, do it away from bedrooms and escape routes with a working smoke alarm nearby.
Can water put out a lithium battery fire?
Do not try to fight it yourself. Get everyone out, call 112 and tell the fire service a lithium battery is involved so they can use the right method.