If your car won’t start, the most likely cause is a flat battery. This happens when you’ve drained the battery more quickly than you’ve recharged it while driving. Forgetting to turn off your headlights, or running the radio and heating while the engine is off, will drain your battery pretty quickly. If you mainly use your vehicle for short journeys, then you may find that over time your battery struggles to recharge itself. If you do have a flat battery, then jump starting your car is the most used solution, and we will tell you what you need, and how to do it.

First Things First

jump start cables hooked to a car battery with another car next to it who will jump start it

It’s a good idea to check a few things to confirm your battery is flat before proceeding further, as there are other reasons that your vehicle won’t start.

Check these three things to see how they are working

  • Dashboard warning lights

  • Interior lights and electric windows

  • Central Locking

If any of these are not working, or the lights are dim, then your battery is probably flat, but there are a few things to bear in mind.

If only the central locking is not working, then it may be an issue with the key fob, and you should try with a spare. If you are unable to turn the ignition key it may be that your front tyre is jammed against the kerb. You can remedy this by turning your steering wheel away from the kerb, or rocking the steering wheel side to side while you turn the key.

If after these steps you are confident that a flat battery is the likely problem, then you can follow this guide to jump start your car.

What You’ll Need

 two hands holding jump starting cables

You’ll need a set of jump leads, one red for positive one black for negative. You’ll also need an appropriate donor vehicle to take your charge from. This car will need to have a battery of the same voltage as yours (usually 12v), and can’t be an electric or hybrid vehicle as the jump start process can damage those vehicles. You’ll need to be able to safely park the donor vehicle close enough to your vehicle to connect the two. It is also best practice to pop on some non-conductive gloves and a pair of goggles when you are connecting the jump leads.

Preparing To Jump Start

There are a couple of safety related steps you should carry out before attempting to jump start a vehicle. Firstly, you should remove any metal jewellery or watches to ensure they don’t contact the battery terminals at any point. Any dangling clothing such as a scarf or tie should be removed to ensure that it doesn’t get tangled with any of the moving parts in the engine.

You should also check the two batteries and the jump leads for any signs of leaking or damage. If there are any issues with either battery or the jump leads, then you shouldn’t attempt the jump start.

Step by Step Guide to Jump Starting Your Vehicle

two road employees trying to jump start a car

  1. Turn It All Off

Before starting, ensure all electrical systems (lights, radio/CD, sat-nav etc.) are switched off in the vehicle receiving charge.

  1. Get In Position

Park the donor vehicle safely as close to the receiving vehicle as possible, without touching, in order to have the jump leads comfortably reach between the vehicles. Turn off both engines, remove the ignition keys, and open their bonnets (or boots if the batteries are located there as is often the case with some manufacturers).

  1. Connect the Red Positive (+) Lead

Attach the red lead to the positive (+) terminal on the flat battery. This often has a red plastic cover over it, which you should pull back to allow access to the terminal. Then connect the other end of the lead to the positive (+) terminal on the charged battery.

  1. Connect the Black Negative (-) Lead

Attach the black lead to the negative (-) terminal on the charged battery. Then, DO NOT connect the other end to the negative (-) terminal on the flat battery. You need to attach the other end of the lead to an earthing point away from the flat battery and fuel system. Some engines have a specific earthing point which you will be able to find in your manual, but any unpainted solid metal part of the engine block or chassis is suitable.

  1. Start the Donor Vehicle

You should wait, with the batteries connected, for 3-4 minutes before starting the donor vehicle’s engine.

  1. Start Your Vehicle

After the donor vehicle’s engine has been running for 1-2 minutes you should start the engine in your vehicle. Leave both engines running for about 10 minutes.

  1. Turn Off and Disconnect

Turn off both car engines, and then carefully disconnect the jump leads. You should disconnect the leads in the reverse order that you attached them. Remove the black negative (-) lead from the earthing point on your vehicle, then from the donor battery. Then remove the red positive lead (+) from both batteries.

You should now be able to start your car engine successfully.

After a Jump Start

If you’ve jump started your car you will still need to fully recharge your battery. You should drive the vehicle for at least half an hour continuously, as stop start traffic will prevent the battery from recharging properly. On average a car battery should last between 3 and 5 years, and you should only consider changing it when it’s showing signs of deterioration. If your battery is still less than 5 years old you should consider regularly driving the vehicle for 30 minutes or more to ensure that it is regularly fully recharging, or investing in a battery charging unit to keep the battery topped up.