How to jump-start a car: A jump-start is a handy way to start a car with a flat battery. But jump leads can cause damage to both cars and people if they’re not used properly. For your safety, and our peace of mind, we’d always prefer you to give us a call and leave the jump starting to our trained mechanics.
If you’re keen to do it yourself, take a look at our advice on how to jump start a car. But make sure you read the instructions in your handbook and follow those if they’re different to our steps. If you have a dead battery, our Battery Assist team can replace a car battery on the same day.
What you’ll need to jump start a car
If you’re planning on carrying out a car battery jump start, you’ll need the following:
- A pair of working jump leads (you can buy AA jump leads here)
- A pair of rubber work gloves (for safety)
- The vehicle with the flat battery, which needs to be in a spot where jump leads can easily reach the battery
- Another vehicle with a fully-charged battery (avoid a hybrid or electric car as this could cause damage)
Using jump leads safely
Before you try to jump start a car or learn how to attach jump leads, remember that batteries produce flammable gases. Here’s how to stay safe:
Check the battery and jump leads
- Never try to jump start a battery that looks damaged or is leaking
- Don’t use jump leads that are damaged
- Stop using the jump leads if they get hot
Make sure the environment is safe
- Before you start, remove any dangling clothing – like a scarf or tie – as it could get caught up in the moving engine parts
- Don’t let any metal objects touch the car batteries – these could cause a spark and possibly make the battery explode. That includes rings, necklaces, watch straps, hand tools, clips, stray wires etc.
- Never smoke or allow naked flames anywhere near either battery
Take care removing the jump leads
- Don’t remove the jump leads while the car engines are running. This can cause serious damage to the cars’ electronics
A step-by-step guide to jump starting a car
If you want to jump start a car with cables, then you’ll need to find someone with a car who’s happy to help. Their car must have a fully charged battery with the same voltage as yours (usually 12 volts).
1. Line up both cars
- Park both cars so their batteries are within easy reach of one another (without the cars actually touching)
- Keep the handbrakes on and the ignitions off
2. Connect the red jump lead
- Use the red jump lead to connect the working battery’s positive (+) terminal to the flat battery’s positive (+) terminal. Never touch the ends of the red and black leads together as this could create sparks and cause vehicle damage
3. Connect the black jump lead
- Take the black jump lead and attach it to the negative (-) terminal on the working battery
- Then attach the other end to an earthing point (unpainted metal on the engine block or chassis) well away from the flat battery and fuel system
4. Start the other car
- Keep both engines off and wait for 3 minutes, then start the working car’s engine and let it run for 1 minute
5. Start your car
- Turn on the engine in the car with a flat battery
6. Let both cars run
- Leave both cars to idle, at a fast pace, for around 10 minutes
7. Turn off and disconnect
- Turn off both cars’ engines and carefully disconnect the leads in the reverse order to the way they were connected (remove the black lead from your car first and finish with the red lead from the other car)
- Make sure the leads don’t touch one another, or either car, as you remove them
8. Restart your car
- Try turning the keys in the ignition to see if your car will start up
9. Call for help
- If your car won’t start there’s probably a more serious problem requiring professional help
- If you’re still stuck, you can call us on 03330 046 046 or by using the AA app
- Get Instant breakdown cover
