How to - Jump starting a car with a Flat battery

So, your car won’t start?

It sounds as though it is trying, but not quite starting? You could be able to jump/push start your car. Read the important information at the bottom of the post before going through these steps.

It is always useful to have a set of jump cables in the boot of the car.
‘Handy things to carry in your car’.

​Steps:

​Step One
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Attempt to start car – If it doesn’t start and you determine it’s the battery, make sure anything that can drain the battery is turned off (e.g. radio, windscreen wipers, etc.). Don’t attempt to start it too much as this will drain the battery further.

Step Two

Find your jump cables – If you don’t have jump cables or a jump starter this could prove to be difficult and you may need to call a recovery service.

Step Three

Call a friend or find a ‘good Samaritan’ (booster car) – You will need another car with the same or similar voltage (most cars are similar). Parked front ends together but not touching.

Step Four

Turn off the booster car – To attach jump cables, turn off the booster car’s power.

Step Five

Attach Positive end of the jump lead to booster car battery and then the other positive end to the flat car battery. Important positive (+) to positive (+)!

Step Six

Attach negative jump lead to negative port on booster car and then an earth point on flat car. Connecting to earth point can be any metal object that earths the car. This can be an object off of the car, for example a sign post. You can connect to the negative point on the flat battery however this may cause sparking and even cause the battery gasses to combust so isn’t advised.

Step Seven
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Once clear, start booster car and leave to run for a few minutes – Start the booster car as soon as possible as to not drain the booster cars battery too much.

Step Eight

Start giving the booster car acceleration in neutral – Giving the car gas will cause more electricity to pass through the cables to the flat battery.
 
Step Nine

Turn the key on the flat car whilst accelerating in neutral – If it starts then great! If it doesn’t, leave it a few more minutes and try again. Once you have been trying for a while with no luck disconnect the jump cables as you don’t want to leave two cars stranded. This may mean you need a new battery or to charge this one up.

Step Ten

If your car has started make sure you disconnect the wires in the same order you connected them in – Do not turn off the flat car until you are either at a garage or at a location that it does not matter if the car doesn’t start. A minimum of 15 minutes driving time at 40mph is advised, however, if you are in a location where the speed limit doesn’t allow that be weary that the car may not gain sufficient charge. Having a completely flat battery can cause it to not take any charge again.

Important Points

• A cars battery is a lot more likely to drain in the winter.
• Never try and jump start a battery where the liquid inside is frozen (this can cause an explosion. Equally do not attempt to warm it. Leave this to a professional).
• Make sure cars are in neutral when parked front to front.
• Do not leave the cars connected with the booster car ignition off as this may drain that car completely.
• If you do not have jump leads or a friend to help jump your car, make sure you are in a built up, safe area when trying to find a Good Samaritan for help.
• Do not get close to the cars once jump leads are connected and attempting to start each car.
• Make sure the terminals (positive + and negative -) are connected to the correct place. Positive to positive and negative to earth.
• It is advisable to wear gloves if your jump leads do not have plastic covers. Rubber soled shoes should also be worn when jumping a car.
• If you are unsure wait for a professional