Updating Map... See why the Art Institute of Chicago is the only museum in the world to be... See why the Art Institute of Chicago is the only museum in the world to be top-ranked by TripAdvisor four years in a row! Experience the greatest Impressionist collection outside Paris, and view contemporary masterpieces in the spectacular Modern Wing.
A battery with 40 amp-hrs of charge will easily start a car that is otherwise ready and willing to go. Less! Anyone with even a decrepit 10-amp battery charger will tell you it doesn't take all day just to get that one crucial start. I've taken a stone-dead battery up to starting power in about 30 minutes.
How long does it take to charge a 12-volt car battery from flat? The two common ways to charge a battery are fast and slow charges. The preferred method is a slow charge as it allows the battery to safely regain all its power.