How to jump start a car

How to jump start a car
How to jump start a car

The cold winter months are tough on cars and particularly their batteries.

Heavy use of lights and heaters can place extra strain on batteries, as does operating in the colder temperatures.

It gets so bad at this time of year that January 2 has been christened flat battery day due to the number of call-outs breakdown companies receive as people head back to work after a few days off.

So knowing how to jump start your car is a useful skill to have yet a recent study by Halfords found that nearly half (46 per cent) of motorists don’t know how to do it.

To avoid being stuck out in the cold, here are the simple steps you need to take if you car’s battery has lost its charge.

Using jump leads

For this you’ll need a set of jump leads and a second car with a similar sized engine. Alternatively a battery booster pack works in much the same way.

First check your battery isn’t leaking or damaged. If it is, don’t attempt to jump start it – it’s time to get a replacement.

  • Make sure all electrical systems such as radios, lights etc are switched off.
  • Position the two cars so their engine bays are close together but the cars aren’t touching. Move any loose metal objects away from both batteries and remove any loose clothing that could get caught and any metal jewellery.
  • Connect one end of the red jump lead to the positive (+) terminal of the working car’s battery, then connect the other end to the positive (+) terminal of the flat battery.
  • Connect one end of the black jump lead to the negative (-) terminal of the working car’s battery and the other end to an earthing point on the other car – this needs to be a solid, paint-free metal point such as a bolt or bracket away from the battery.
  • Start the engine of the working car and allow it to run for a minute or two then try to start the other car. If the battery is very depleted it could take a few attempts.
  • Once the failed car has started leave both cars running for around five minutes before removing the leads.
  • Remove the leads in the reverse order to which you attached them. Make sure they don’t touch any metal surface or get caught in any moving parts.
  • You then need to drive the failed car for 15 minutes or preferably longer in normal conditions (not heavy traffic) to get some charge back into the battery.

If your car won’t start after following these steps you battery has most likely failed completely, in which case you’ll need a new one.

Bump starting

how to jump start a car
Bump starting isn’t as safe or reliable as using jump leads. Picture: Shutterstock

This method isn’t as safe or reliable as using jump leads so we’d recommend avoiding it unless you’re absolutely desperate. It also only works on cars with manual transmission.

For this you’ll need a couple of helpers to push the car.

  • Start by putting the car in second gear and turning the ignition on.
  • Get your helpers to start pushing the car, making sure it’s safe to do so.
  • Once the car is moving at at least 5mph let out the clutch quickly. This should engage the transmission and allow the turning of the wheels to get the engine spinning.
  • Once it’s running, stop but let the engine run for at least 15 minutes to put some charge back in the battery.