I really wasnt sure where to put this, but figured I would get the most help here. Mods, move if appropriate.

I want to wire my radiator fans to a manual switch for the track, but was affraid of the battery drain on it. So I thought about solution using a relay and potientiameter. Using say a 12 volt relay, and a pot to dial in the exact trip voltage, to

 

I've left my fans on for up to an hour at the track before with no problem. This sounds like a good idea though.

 

Just bring a set of booster cables to the track.