Why cant you connect the black jumper cable to the dead batterys negative (–) terminal? This is so you can avoid sparks from occurring near the battery where flammable hydrogen gas may be present, resulting in a possible explosion.

Can you connect negative to negative when jumping a car?

Caution: Dont attach the negative cable to the negative terminal of the weak battery when jumping a car battery! This common mistake could ignite hydrogen gas directly over the battery. If it doesnt start, shut off both ignitions, make sure the cable clamps are making good contact and then try it again.

What happens if you put the negative jumper cable?

When jumpstarting a vehicle, the final connection should be to a good ground on the vehicle with the dead battery. Connecting the jumper cable to the negative terminal of the dead battery can create sparks and potentially cause an explosion.

Do you jumpstart a dead battery connect the negative cable to?

Turn off the ignition on both cars. First, clamp one end of the positive cable to the dead batterys positive clamp. Next, connect the negative cable to the negative terminal on the good battery. Finally, connect the other end of the negative cable to a ground on the vehicle with the dead battery.