I had a full garage during a house move, my GT is a second car too so was parked outside, I shoved the CTEK under the car out of the rain, it was fine, in fact, I think they are rainproof and used on boats, check out the web site. This way you only have the thin wire going into the boot.As my GT is a second car I was thinking of using a battery tender to keep it charged. However my car lives outside. Is it a good or bad thing to have it in the boot?