You can charge a 12-volt car battery by using a battery charger or another vehicle. If you're near an electrical socket, use a car battery charger. Most modern car battery chargers provide the option of a rapid charge or a 12-hour charge. If you are having trouble with your battery and you don't have access to battery charger, you can give your 12-volt car battery a quick charge by connecting it to another vehicle. Either way, the process is simple and requires only a few tools.
Disconnect the cables from your car battery using a spanner or wrench. Tuck the cables out of the way so they cannot touch the battery.
Place your 12-volt battery charger near your car battery and an electrical socket. Set the battery charger to 12 volts.
Attach the black (negative) cable from the battery charger to the negative terminal of your car battery.
Attach the red (positive) cable from the battery charger to the positive terminal on your car battery. Check to make sure there's a good connection to both terminals.
Plug the battery charger into an electrical socket. Turn on the battery charger to begin charging your 12-volt car battery.
Make sure that the other vehicle has a 12-volt battery.
Position the other vehicle as close as possible so that the batteries can be connected using jump leads. Make sure the engine is turned off. Use a spanner or wrench to disconnect the battery cables from your car battery. Don't disconnect the battery cables from the other vehicle.
Connect the black (negative) battery cable to the negative terminal on your battery. Connect the red (positive) battery cable to the positive terminal on your battery. Make sure that the cables don't touch each other or either vehicle.
Connect the other end of the black (negative) cable to the negative terminal of the other vehicle. Connect the other end of the red (positive) cable to the positive terminal of the other vehicle. Check to make sure that the cables are firmly connected to the battery terminal and that the cables do not run over moving parts of either engine.
Start the engine of the other vehicle. Your car battery will start to charge.
Use another vehicle to charge your battery only if you have to. Your battery will usually be charged enough to start your car after 10 or 15 minutes. Gently revving the engine of the other vehicle increases the charge. Make sure you disconnect the jump leads from both cars before reconnecting the battery to your car.