How to jump start a car


Jump starting a car is the most common way to start a car in the event of a flat battery. However, it can be dangerous to jump start a car if you are not aware of how to use jump leads properly. Follow our step-by-step guide or watch our video to ensure you don’t put yourself in danger.


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What you'll need

  • Jump leads

    You’ll need a set of working jump leads that have no faults, to link the flat car battery to the working battery of another car.

  • A donor car

    You’ll need a donor car with a working battery to transfer electricity to the flat battery on your car.

  • Safety goggles

    Sometimes there are dangerous sparks created when jump starting a car. To protect your eyes, you should always wear safety goggles.


How to remain safe when using jump leads


When jump starting a car, it is important that you don’t take any risks. Below we have explained how to remain safe:

  • Check for any damage to either car batteries or the jump leads. If there is any leaking or damage you shouldn’t attempt a jump start. If the jump leads become hot at any point you should immediately stop using them.

  • Make sure that the clothing you’re wearing is suitable. We would recommend removing any metal, including rings and accessories and any loose clothing, such as scarves.

  • The engine should be off when the jump leads are removed. If you remove the jump leads while either engines are running you could damage the electronics.

  • Never put naked flames close to the battery - this includes smoking.


How to jump start a car: step-by-step

  • Position the two cars

    You’ll need to park the car with a flat battery and the car with a charged battery nose-to-nose. You should ensure enough space is left between each car to open both bonnets and connect the jump leads.

  • Make sure you’re safe

    Before you jump start your car you should remove any loose clothing that could get tangled in the engine, remove any metal jewelry and put on your protective glasses.

  • Attach the red jump lead

    With both ignitions turned off and the parking brakes engaged on both cars, you should attach the red lead to the donor car's positive (+) terminal and the other end to the flat battery’s positive (+) terminal.

  • Attach the black jump lead

    Once the red jump lead is attached, you should attach the black jump lead to the negative (-) terminal on the donor car. The other side of the jump lead should be attached to an unpainted metal surface, well away from the fuel system and the battery on the car with a flat battery as an earthing point.

  • Start the donor vehicle

    After all jump leads are attached to the correct places, you should start the engine of the donor vehicle and allow it to run for 3-5 minutes. The donor vehicle should remain in park or neutral, with the handbrake locked.

  • Start the car with a flat battery

    After the donor vehicle has been running for 3-5 minutes, you should start the car with the flat battery.

  • Allow both cars to run

    Leave both cars in idle and allow them to run for 10 minutes with the jump leads still attached.

  • Turn off both cars and disconnect the cables

    After both cars have been left to run for 10 minutes, you should turn off both cars. Only once both cars are turned off should you begin removing the cables - this should be done in reverse order to how they were applied. It’s important that the cables don’t touch each other when they’re being removed.

  • Run the car with a flat battery

    Once all jump leads have been safely removed you should turn on the car with a newly charged battery and leave it running for 15-20 minutes. After this, you should drive the car for 20-30 minutes on a route where you’re unlikely to stop and start regularly to recharge your car’s battery further.


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