A dead battery can be a real headache. But if you carry jumper cables in your car and know how to use them properly, your problem is solved. Once your car engine is running, and if the battery is still good, the alternator will recharge it. If the battery is bad, at least you can drive to an auto parts store to buy a replacement battery. Often, stores will install batteries for free. Jump-starting a car is easy, but you should do it with caution.