Anyone use a battery isolator on a dual battery drag car

On my drag car I only have one battery. I have a 95 amp alternator, and a wide open throttle micro switch on the carb, that opens the alt field circuit at WOT. Any other time the charging system works normally. Also have a time delay relay on the fan/water pump system, that turns them off after a preset (adjustable) time, so I don't kill the battery, if I get running my mouth and forget to turn them off.