My current bracket car has two group 24 marine/RV deep cycle batteries in it, I charge them for two to three days at 2 to 6 amps before going to the track to race, I don't charge them between time runs or between races but I do charge them during the lunch break I don't start and shut the car off to move it up in the lanes to move up for one or two spaces either, I'll wait for 5 or more spaces before starting the car to move it up