How to start a car with jump leads.
Make sure that your jump leads are not damaged as this can mean that they overheat and catch fire.
Keep all metal objects out the way when you are trying to jump start a car as any contact with the battery can cause a spark and may explode the battery.
Don’t jump start a car if the battery is damaged or leaking.
Batteries give off flammable gases so don’t smoke or use any naked flames near to it as this could cause an explosion.
Make sure you keep your hands and any loose clothing well away as these could get caught up in moving parts of the engine and cause injuries.
Before you connect the jump leads make sure that the vehicles in use have the same voltage and they are not touching as this can cause explosions. Both vehicles should also be parked with their handbrakes on and the ignition off.
- The red jump lead needs to be connected from the (+) positive terminal of the donor vehicle’s good battery to the (+) positive terminal of the flat battery.
- Use the black lead to connect the (-) negative terminal of the good battery to a suitable earthing position on the engine or chassis of the other vehicle. The earthing point should be away from the battery and fuel system.
- Once both leads are connected you need to wait three minutes for the voltages to equalise before starting the engines.
- Start the engine of the donor car and make sure it is running for at least one minute. Start the other car whilst the donor car is still running and leave both engines running at a fast idle for at least ten minutes.
- Don’t remove the jump leads whilst the engines are still running as this can cause damage to the electronics of the cars.
- If the jump leads get hot switch off both engines to avoid them over heating and causing a fire. Don’t turn the engines back on until the leads have cooled down properly.
- Turn off the ignition on both cars and then disconnect the leads carefully in the reverse order to the way that they were connected. Be careful not to touch the clips together or against the bodywork of the cars.
- Start the car with the dead battery using its own battery power. If the car fails to start then it could have a more serious problem and you may need to call a breakdown service or garage.
Battery voltage is reduced by cold and prolonged downtime. If you drive your car infrequently the battery voltage can decrease due to internal consumers (e.g. clock and computers etc).
Purchase a "trickle charger" to top up your battery. Have your battery voltage checked at your garage. Your garage will probably check the battery as a part of their eVHC or health check but definitely worth mentioning any difficulty in starting at a regular maintenance visit.
On average, a battery should be checked once a year. Do you usually drive short distances or is the car often stationary? Then we recommend that you have the battery checked more often.