Car Battery Cable Order: Which to Connect First
Improperly connecting a car battery cable when jump starting your car can cause serious damage to your car, the car supplying the jump and possibly cause severe injuries from burns to you and the helpful motorist supplying the jump. The charge and discharge cycle of a battery causes hydrogen gases to build up. These gases escape through vented cell caps and can accumulate around the battery. If you connect the jumper cables incorrectly, you can create a much large spark than normal and this spark can ignite these gases and cause an explosion.
1. Connect Positive Cables First
Connect one positive or red cable end to the positive or red terminal on the dead battery. Connect the other end to the positive terminal on the good battery.
2. Connect Good Negative
Attach the negative or black clamp to the negative terminal on the supply battery.
3. Start the Supply Engine
With both positive cables connected and the negative connected to the good battery, start the supply car's engine.
4. Connect Negative Cable to Ground
Find a clean metal component under the hood on the car being jump started and connect the negative cable end to it.
5. Start the Car
Allow the dead battery to charge for a minute or two and then attempt to start it. If it doesn't start right away, allow the supply battery to charge the dead one for at least five minutes and attempt to start it again.
6. Disconnect Immediately
Once the car being jumped is running, disconnect both negative cables and then both positive cables immediately. Allowing the jumper cables to remain connected can cause problems with the ignition modules and computers on both cars.
Before you attempt to jump start your dead battery, make sure both terminals on both batteries are clean, otherwise optimum electrical transfer won't be able to happen.