How to jump start a car in 10 steps (with video)

How to jump start a car in 10 steps (with video)
It’s a horrible feeling - jump in the car on a winter’s morning, turn the key, and the starter motor groans and fails to fire up the engine.

This may mean a dead battery but, if your battery is merely flat it may just need a jump start to get it going again.

If you're not sure that the issue is definitely being caused by the battery, find out how to tell if you have a flat battery here.

How to jump start a car with jump leads

The most common and effective means of getting your car going with a flat battery is by using jump leads.

What do I need to jump start a car with jump leads?

Jump start your car guide
Typical car battery

 

Safety precautions before jump starting a car with jump leads

When jump starting a vehicle, it’s important not to take risks.

Consult your owners manual first and if you’re not confident that you know what you’re doing, give RAC Breakdown a call on 0330 159 1111 and we’ll be happy to help.

  • Check for damage - if there’s any obvious damage to either of the batteries, or the jump leads, don’t risk attempting a jump start
  • Remove any rings or metal jewellery you’re wearing and make sure nothing metal touches the terminals on the battery.

Ten steps to jump start a car

  1. Before starting, make sure any electrical systems or devices in the vehicle with the dead battery are switched off (Lights, radio/CD, sat-nav etc) and if possible, lower the drivers window. 
  2. Park the second vehicle as close to the casualty vehicle as possible, without the vehicles touching, ensuring the jump leads will comfortably reach from one battery to the other.
  3. Ensure both vehicles engines are switched off, remove the ignition keys and open their bonnets (or boot if the battery’s located there). 
  4. Attach one end of the red jump lead to the positive terminal on the flat battery. The positive terminal will usually have a red plastic cover with a plus (+) symbol on it. Pull the cover back to access the terminal.
  5. Then attach the other end of the red jump lead to the positive terminal of the good battery on the second vehicle.
  6. Attach one end of the black jump lead to the negative terminal of the good battery.
  7. Then attach the other end of the black jump lead to a good earth point on the casualty vehicle – a solid metal part of the engine is usually best.
  8. Now attempt to start the casualty vehicle. If it doesn’t start after a few attempts, it might be more serious than a flat battery. In this event, seek professional help by calling the RAC on 0330 159 1111.
  9. If it does start, leave it running for about five minutes.
  10. Switch off the casualty vehicle, disconnect the negative jump lead then check the engine starts again okay. Disconnect the remaining jump leads.
Jump start your car guide - earth
Attach the other end of the black jump lead to a good earth point on the casualty vehicle – a solid metal part of the engine is usually best

 

How to safely remove the jump leads

  1. Switch off the engines on both vehicles
  2. Disconnect the black jump lead that is connected to the casualty vehicle
  3. Disconnect the other end of the black jump lead from the second vehicle
  4. Disconnect the red jump lead that is connected to the second vehicle
  5. Disconnect the other end of the red jump lead from the battery on the casualty vehicle

After the leads have been removed

Restart the engine on the casualty vehicle.

The battery will need to recharge fully for it to be fully serviceable, which is best achieved using a quality battery charger for several hours.

In the meantime, if possible, drive the vehicle normally (not in heavy traffic) for around 30 mins to try to put some charge back into the battery.

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Bump starting a car

The RAC do not recommend bump starting vehicles. 

Please follow the advice in the How to jump start a car with jump leads or How to jump start a car with a portable battery pack sections.

How to jump start a car with a portable battery pack

RAC-jump-start-guide-booster

If you're worried about getting stranded with a flat battery when you are unable to call for help or seek assistance from someone, then you can buy a portable battery pack as a precaution, to keep you mobile if your battery goes flat.

These can be purchased from the RAC shop and are able to jump start a car without the use of another vehicle.

Before you start

When jump starting a vehicle, it’s important not to take risks. Consult your owners manual first and If you’re not confident that you know what you’re doing, give the RAC a call on 0330 159 1111 and we’ll be happy to help.

  • Check for damage - if there’s any obvious damage to either of the batteries, or the jump leads, don’t risk attempting a jump start
  • Remove any rings or metal jewellery you’re wearing and make sure nothing metal touches the terminals on the battery.

Jump starting with a portable battery pack

First check that the battery pack is fully charged.

Locate the vehicle battery - usually situated in the engine bay under the bonnet, but in some vehicles, it is located in the boot. It’ll probably be hidden under a plastic cover – unclip this and you should see the battery with its two terminals.

Connect the positive (red) lead from the battery pack to the positive (+) terminal of the battery. Connect the negative (black) lead to a good earth point on the casualty vehicle – a solid metal part of the engine is usually best.

Stand the battery pack on the ground next to the vehicle, the leads are usually long enough to reach the battery. Avoid placing it on the engine as it might fall off when the engine starts.

Once the battery pack is connected, switch on the pack and attempt to start the vehicle as you normally would. If it doesn’t start after a few attempts, it might be more serious than a flat battery. In this event, seek professional help by calling the RAC on 0330 159 1111.

If the vehicle does start, keep the engine running for about 5 minutes. Switch off the engine, then switch off the battery pack and remove the leads from the battery pack. Now restart the engine again.

The vehicles’ battery will need to recharge fully for it to be fully serviceable, which is best achieved using a quality battery charger for several hours. In the meantime, if possible, drive the vehicle normally (not heavy traffic) for around 30 mins to try to put some charge back into the battery.

 

If your MOT is due or if you would like to book your vehicle in for a full car service, you can book online with your local RAC Approved Garage today.

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Jump starting a car FAQs

  • Will my car start again after being jumped?

    Once you’ve jump started your car, you should drive for at least 30 minutes (in normal driving conditions, not heavy traffic) before stopping to give your battery long enough to build up some charge.

    If you don’t drive for long enough before stopping, it’s likely you’ll need another jump start after you’ve stopped, which could put undue stress on your vehicle.

  • How do you jump start a car without another car?

    If you’re concerned you’ll need to jump start your car when you don’t have access to another vehicle, you might want to invest in a portable battery pack that you can keep in your car.

    This will ensure you can charge your battery on-the-move in case you get stranded. The RAC does not recommend push starting your car.

  • Can I drive my car after a jump start?

    Yes, although you should let your car’s battery charge up sufficiently before attempting to drive it, to avoid putting you or other road users at risk.

    If jump starting from another vehicle, leave both vehicles running for at least 5 minutes before attempting to drive your car. If jump starting from a battery pack, leave your battery to charge for as long as possible before driving.

  • Can a car battery be too dead to jump start?

    It’s possible to jump start a battery even if it’s ‘dead’ by following the advice on this page. However, if your car doesn’t start, it could signal an underlying problem with your battery – meaning it needs replacing – or another electrical issue with your car.

  • What do I do when my car battery dies?

    If your car battery dies, you have two options to try and jump start it yourself.

    Firstly, you can use jumper cables to jump start your car from another vehicle with a good-quality battery.

    The second option is charging your battery using a portable charger. You should avoid push starting your car.

    If you’re driving in Europe and your car battery dies, European breakdown cover will be able to help cover the cost of any repairs.

  • Is it bad to push start a car?

    The RAC does not recommend push starting or bump starting a vehicle, please follow the advice in the How to jump start a car with jump leads or How to jump start a car with a portable battery pack sections.

  • Does jump starting a car drain your battery?

    If you’ve been asked to help jump start a friend’s battery, you run the risk of frying one or both of the batteries if your battery is old or damaged in any way. Ensure your battery is in good condition before offering to help jump start anyone else’s car.

  • How do you tell if it's your battery or alternator that’s faulty?

    It can be difficult to know whether it’s your battery or alternator that’s at fault if you’re having issues with starting your engine, but there are some indicators you should watch for.

    If your battery’s at fault, your battery warning light may be illuminated or your engine may need regular jumping. Tell-tale signs of your alternator being at fault are headlights and dashboard lights that are dimmer than usual, or your engine dying soon after a jump start.

  • How do you jump start a completely dead car battery?

    Even if you think your battery is completely ‘dead’, it’s still possible to jump start it by following the advice on this page.

    However, if your car doesn’t start, it could signal an underlying problem with your battery – meaning it needs replacing completely – or another electrical issue with your car.

  • Can you recharge a dead car battery?

    It’s possible to jump start a battery even if it’s ‘dead’ by following the advice on this page.

    However, if your car doesn’t start, it could signal an underlying problem with your battery – meaning it needs replacing completely – or another electrical issue with your car.

  • What if a jump start doesn't work?

    If your attempts to jump start your car don’t work, it could be the sign of your car having a more serious underlying issue with its battery and/or electrical system.

  • Is jump starting a car dangerous?

    Providing you follow the advice laid out on this page, it should be safe to jump start your car with either another vehicle’s battery or a portable battery pack.

    However, before attempting to jump start a battery, ensure it’s not cracked or leaking as this could lead to an explosion and be sure not to smoke around either vehicle or lean over the battery of either car.

  • Do I need to jump my car every time?

    Car batteries go flat for a number of reasons, from something as simple as leaving your lights on to more serious faults with your car’s electronics.

    However, if your battery needs jump starting every time you use it, it’s likely your vehicle has a more serious underlying problem with its electrical system or your battery needs replacing.

  • Is it safe to jump start a car in the rain?

    Jump starting your car in the rain is no more dangerous than doing so on a dry, sunny day although you may want to invest in an umbrella to stop you from getting soaked.

  • What happens if you jump your car wrong?

    Unfortunately, there are plenty of things that could go wrong with your car if you jump it incorrectly.

    This includes damage to your battery, alternator and jumper leads which can lead to a costly replacement bill, so save yourself some money and follow the advice on this page correctly.

  • Can you remove jumper cables while the car is on?

    In order to keep yourself safe and avoid any damage to your vehicle, you should disconnect the black clamp from the car being jumped, then the other black end from the ‘good’ car, then the red clamp from the ‘good’ car, and finally the last red clamp from the jumped car.

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