How to Jump Start Your Car

We have all been there – Go to start the car and the battery is flat! Not only can this cause an issue but knowing how to get it started again can be a pain.

While using jump leads might seem simple enough, they can be really dangerous so please take care when attempting to jump-start a car.

There are a couple of ways to do this if you need to but, in all honesty, the best bet is to call out breakdown or get the car recovered to us so we can check it over.

If you are confident enough and have the right tools there are a few ways of jump-starting your car, all can be very effective.

Using jump leads safely

Before you try to jump-start a car, 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. Check for this before you attempt to jump-start your car.
  • 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 loose clothing 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 jewellery, 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

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 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.

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.

How to remove the jump leads

You remove the jump leads in the reverse order to how you attached them. But if you’re not sure, here are the steps:

  • Switch off the engines on both vehicles.
  • Take the black jump lead off the earthing point.
  • Remove the other end of the black jump lead from the working battery’s negative (-) terminal.
  • Disconnect the red jump lead from the working battery’s positive (+) terminal.
  • Remove the other end of the red jump lead from the positive (+) terminal on the flat battery.

How to jump-start a car with a battery booster pack

It can be a good idea to keep a car battery booster pack in your car. That way, you can jump-start your battery even if you can’t get another car to help you.

Before you start, make sure:

  • The car battery doesn’t look damaged and isn’t leaking.
  • You’ve taken off any metal jewellery or watches and removed dangling clothing like a tie or scarf.


Steps to using a car battery booster:

1. Check the battery booster

  • Make sure the pack is fully charged
  • Put the battery booster pack somewhere stable. Don’t put it on the engine as it might fall off when the engine starts.

2. Connect the red jump lead

  • Connect the red positive (+) jump lead from the battery pack to the positive (+) terminal of the car battery.

3. Connect the black jump lead

  • Connect the black negative (-) jump lead to an earthing point on your car. Unpainted metal on the engine block or chassis is best.

4. Switch on the pack

  • Once the battery pack is connected, switch on the pack.

5. Try to start the car

  • Try to start your car by turning the key in the ignition.
  • If it doesn’t start after a few tries, there’s probably a more serious problem that needs professional help.

6. Let the engine run

  • If the car starts, keep the engine running for about 5 minutes.
  • After 5 minutes, switch off the boost pack and allow the engine to run for a further 5 to 10 minutes.

7. Turn off and disconnect

  • Turn off the engine.
  • Remove the leads in the reverse order to how you placed them on (first disconnect the black lead, then the red lead).

8. Restart your car

  • Try turning the keys in the ignition to see if the car starts up again.
  • If you’ve managed to jump-start your car, the engine will need to recharge again fully.
  • Charge the engine by driving normally (not in stop-start traffic) for at least 30 minutes.

How often should you change a car battery?

On average, batteries last between 5 and 7 years but you should only consider changing a car battery when it’s showing signs of deterioration.

If the battery is more than 5 years old and seems like it’s struggling to start the car, get it checked out. It’s better to be safe than sorry – it’ll be worse if it’s a roadside emergency or on a cold morning when you’re already late for work.

Car Friend offer FREE battery checks; it takes less than five minutes, and we can give you a good indication of the health and charge of your battery. We can also offer a battery condition charge or advise on the best replacements available for your car if it needs it.

All our batteries come with a warranty ranging from 3 to 5 years. This means should your new battery fail within this time we will replace it with a new one – no fuss – no problem and best of all no cost to you.

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