How long should i charge a car battery?
You can charge it a number of different ways. DO NOT run the car and hope for the alternator to charge it. The alternator is only used for maintaining a charge, not for recharge. This will in some circumstances (especially with fords) cause the alternator to overheat and fail. Go to your local Advance Auto Parts store. They can throw it on the fast charge (35 minutes), the Full charge (4 hours), or the 1 amp trickle charger and leave it overnight. EDIT: this is a free service, testing as well. If you’re planning on letting the car sit, I’d invest in a 1 amp trickle/maintenance charger that way this won’t repeat itself again.