How long do you have to run a car engine to charge a fully discharged battery?
The amount of time needed to charge a fully discharged car battery depends on several factors, such as the battery's capacity, the alternator's output, and the condition of the battery. Typically, a car battery can be charged fully by driving the vehicle for at least 30 minutes to an hour. However, if the battery is severely discharged, it may take several hours of driving or using a battery charger to fully charge it.