How long does it take to charge a car battery while driving?
A generator charges your battery while you’re driving. So if you don’t have access to a charger, you can still try charging your battery this way, as long as you can start your car. The amount of time it takes depends on a few factors, but it’s usually between 15 and 60 minutes.
Of course, a fully discharged battery will take longer to charge than one that’s less discharged. If your battery is completely dead, you probably won’t even be able to fully charge it by just driving the car, but you can at least drive long enough to get to the charger.
The overall condition of your battery also affects charging speed. If you drive your car regularly, your battery will usually charge faster and last longer than a battery in a car that’s only driven occasionally, so your car’s usage cycle is a factor. Older batteries can be harder to restore charge.
Different vehicles have different battery sizes and charge capacities, which can also affect charging times. Because engine speed (measured in RPM (revolutions per minute)) is directly related to the voltage delivered by the generator, it’s a good idea to keep your vehicle at a higher speed while charging (always above 1,000 RPM).
Keep in mind that in terms of gears, faster doesn’t necessarily mean higher RPM. If your car doesn’t have a tachometer on the dashboard, listen to the engine a little higher and try to keep it there. However, automatic transmissions will often downshift when possible to get the revs down, so highway speeds may be necessary in these vehicles to achieve the best payload.
When driving to charge your battery, turn off all unnecessary equipment, such as the radio, to ensure that as much of the energy generated by the alternator flows directly to the battery as possible.
