What is the best way to keep a battery charged on a car thats not going anywhere?
If you disconnect the battery, there’s no need to start the car. When leaving the battery connected, all of the computers in the car will draw a small amount of current, just to “keep alive.” Cranking the engine is the largest draw a car’s battery will ever encounter. My own testing has shown me that, generally, instantly after cranking the car, the battery itself constitutes a draw of about 30-40 amps. That is, the alternator has to output 40 extra amps just to recharge the huge expenditure of amperage used to start the car. This inrush lasts about two minutes. After that initial period, the battery current draw starts to drop off pretty quickly. After ten minutes of idling, a healthy battery typically draws less than 10 amps (and usually even less than 5 amps). That being said, if you’re concerned about preserving your battery, the best thing to do is either leave it disconnected, or attach a trickle charger. Running your car for ten minutes a week during the cold winter isn’t really
