For how little a battery is used in your car---only when the starter engine is cranking---its failure can mean only one thing: You're stuck. Fortunately, most modern car batteries can take a charge and be brought back from the dead so your car will start the next time you turn the key. Depending upon the make of your car and equipment available, there are several options to getting volts flowing back into your battery.
The best and recommended way to charge a dead car battery is with a battery charger. These chargers connect to battery terminals using alligator clamps and transfer current from a power source back into a dead battery. This recharge process isn't instant and may take up to an hour depending upon the type of charger. Chargers are available in sizes that range from commercial grade ones found in a professional garage that plug into an outlet to draw their power to portable versions that can be stored in a car's trunk that draw power from a pre-charged battery or through another vehicle's lighter input. To avoid receiving a shock when using a charger, operators must connect the negative terminal first, connecting to the black terminal before connecting to the red one.
Jump Start to Charge
The most common method used to start a car with a dead battery will also provide a charge to a worn-out one. Although you'll need a pair of jumper cables and a friend with a car with enough electrical power to crank your starter to get your engine running, once your engine is operating, your serpentine belt will create power from your alternator. A car's alternator provides electrical current while the engine is running and, when operating long enough, produces enough excess electricity to charge a dead battery. A long drive may give your battery the electricity it needs to be replenished. As with charging a battery, connect jumper cables to a grounded point on the engine block before completing the circuit by connecting cables to the red terminals.
Push Start to Charge
Owners of manual tramsmission vehicles don't need extra equipment to start their car when its battery is dead. Place the car in neutral and push until it's rolling 3-4 mph. Place the car in gear by engaging the clutch; if the wheels are turning fast enough, it will force the engine to turn over on its own. The car can then be driven as the alternator charges the battery in the same manner as if was started using jumper cables.
Over time, car batteries will lose their charge if the car's not driven. Owners of cars who don't plan on driving them often enough to keep the battery replenished by the alternator can attach a solar charger to feed current into a battery's storage cells. Solar chargers aren't usually designed to charge a dead battery enough to start a car, but rather to maintain a charge over a long period of time and don't provide much in the way of excess current.