How long to charge a car battery with 12 volt charger?
How long to charge a car battery with 12 volt charger? A trickle charger usually operates at around 2 amps and it is going to take a long time to charge up your 12 volt car battery (read our full guide here). Is the battery light on but battery charging OK? Going nuts - Battery light on but battery charging OK. The battery light is on but the voltmeter says 13.5 to 14.5 volts depending on the engine revs. When engine is off the volts drop to about 12. What does it mean when your car battery light is on?...