Oh, wait a tic. A stand alone battery? As in not running a vehicle. Well, that's a different story. Takes a bit of amps to initially start a car. A stand alone can fill for quite awhile as long as you're not using it for any other needs. When I say kill a battery, i mean dropping amperage enough that it won't crank the engine. Sometimes that isn't much, depending on the battery you have in your vehicle.