Using a car battery charger | How a Car Works
An average car battery has a capacity of around 48 amp hours which means that, fully charged, it delivers 1 amp for 48 hours, 2 amps for 24 hours, 8 amps for 6 hours and so on. A basic charger usually charges at around 2 amps - and so needs 24 hours to deliver the 48 amps needed to fully charge a flat, 48 amp hour battery.
