If you inadvertently leave your lights on and drain your battery, take the following precautions to prevent damage to the battery and the starter when jump-starting your car:
- Don’t risk causing the battery to explode. With both cars off, connect a positive cable end to the positive battery terminal of the dead battery.
- Connect the other positive cable end to the positive terminal of the source battery.
- Connect a negative cable end to the negative terminal of the source battery.
- Attach the remaining negative cable to unpainted metal on the car engine (as far from the dead battery as possible).
- Wait a few minutes and try to start the disabled car. If it doesn’t start, start the source car and then try starting the dead one again.
- When the car starts, be careful to disconnect the cables in the reverse order.
- If the car still doesn’t start, don’t keep trying to charge it or you are liable to damage the starter. Bring the battery to an automotive shop to see if it can be recharged.
- Even if you’re successful, ensure a full recharge by hooking up the battery to a charger overnight or by driving the car for 5 or 10 miles (8 to 16 km).