How to Jump Start a Car

Hopefully, you will never need this advice, however, flat batteries do happen – at such times knowing how to jump start a car can be the quickest way to get you mobile again.

Although a new battery should give a number of year’s trouble free motoring, usually somewhere between three and five years, there are a several reasons you may find your battery drained of energy and, temporarily at least, you have a problem that leaves you stranded and unable to make or continue your journey.

Knowing how to jump start a car is a get out of trouble quickly solution that all motorists should be familiar with and prepared for. As with most things, there is a right way and a wrong way to jump start a car – a safe way, and a way how not to do it. Jump starting a car can pose a personal safety risk if not carried out correctly.

For safety reasons it is advised to remove metallic objects such as bracelets, rings, and watches before connecting jump lead connections. Ensure no loose clothing can become entrapped in working parts of the engine whilst working under the vehicles bonnet

In this short article we set out the steps to follow which will give your engine the much needed boost of lie that will get you moving again. It may be helpful at this point to reflect on the reasons why a car battery runs flat – click on our article why has my car battery died, here the various reasons are explained, with tips on how to avoid this inconvenient and frustrating problem.

Which type of battery do you use?

The most common battery used in standard cars today is a 12-volt battery. Other vehicles such as heavy goods vehicles and military vehicles need a much bigger battery to sustain their high power usage, which is basically a unit consisting of two 12 volt batteries combined.

How to jump start a 12 volt battery

Firstly, switch off your engine making sure all electronic devices are also switched off. For example, lights, CD player and radio, navigational system, gaming, and any other devices that drain power from the battery. Remove your key from the ignition.

The ignition of the vehicle you are using to give the all important boost/ jump start should also be turned off whilst connecting the jump leads.

Position the boosting vehicle a short distance – not touching – away from the vehicle containing the flat battery, just enough for the cables to reach from one battery to the other. Then, connect one end of the red positive lead to the positive battery terminal of the dead battery, and the other end to the live battery positive pole.

Next, attach one end of the black negative lead to the black negative battery terminal pole of the booster vehicle, and connect the other end to a metal earthing point such as a bolt or bracket, away from the flat battery. Ensure all four grips are secure.

Start the engine of the working vehicle allowing it to run for a few minutes before turning on the ignition of the vehicle containing the flat battery.

After the flat battery has fired up and the engine is running for a minute or so, remove the jump cables in reverse order i.e. the black negative cable then the red positive cable. Your vehicle should now be ready for the road.

Using a battery booster/charging pack

As before, turn off all electrical devices in the car and make sure your ignition key is removed.

Make sure the battery booster/charging pack is in the off position at this stage.

Connect the red positive lead to the positive terminal on the battery then connect the black negative lead to an uncovered (earthing) metallic part of the engine.

Switch on the booster pack which will charge the flat battery.

Turn on the engine and switch off the battery pack. Remove all cables in reverse order starting with the black negative cable first.

How to jump start a 24 volt battery

A 24 Volt battery is simply two 12 volt batteries combined in one unit and you can use the same boosting processes detailed above. When changing over the cables from one battery to the other make sure that you turn the engine off on the assisting vehicle or booster pack before removing and reconnecting the cables.

You can charge both batteries at the same time using a working vehicle and a booster pack.

Make sure the booster/charging pack is switched off before connecting it to the battery unit. Connect the red positive cable to the positive terminal and black negative cable to a bare metal connection not less 45cm away from the battery.

For the second battery attach the jumper leads as per the instructions above.

Switch on the booster pack and turn on the engine of the assisting vehicle. Allow the engine to run for a few minutes.

Switch on the ignition of the dead battery vehicle and switch off the engine of the assistance/booster vehicle. Once the flat battery has received the all important boost, let it run for a few minutes to give it charge.

Switch off the engine of the car that had the flat battery, and has now hopefully been jumped into life, then switch off and remove the booster pack making sure you remove the negative cable first.

Make sure that the battery pack is not removed whist the engine is still running.

Restart the car and remove the other cables.

By following the above steps you should be back on the road again within a short time. Once you are up and running again, a lengthy journey will help give your battery the opportunity to recharge itself – but consider why the battery has flattened in the first place? How old is your battery?  Is it time for a new car battery? If so, then click here to view our extensive range of new car batteries

And do please remember, if jump starting your flat battery is not an option, simply call us for assistance, that’s why we are here.

Whichever battery you have, make sure you use the right charger. Choose the correct charger for your battery by clicking on the link, or if you would prefer to speak with one of our advisors regarding the appropriate battery or charger for your vehicle, then give us a call on 0800 8620676. We are here to help.

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