And what if your car won’t start because of a dead battery? To revive a dead battery, first make sure each car is in park or neutral -- and turned off. Then, connect one end of the cable to the positive terminal of the donor battery, and then connect the other end to the positive terminal of the dead battery. Let the dead battery charge for a few minutes, and then turn the ignition on the vehicle of the dead battery to see if it starts. This only applies if you:a) Have someone to take you to a repair shop or the store right away to buy a new battery.