I had this charger on my plastic 10 ft fishing boat for years. I screwed it right onto the inside of the boat. I never took it out. It sat in the elements through cold new England winters. It was submerged many times when it rained hard and filled up with water. Also fished a year with a hole in the boat and it was submerged every trip. it always worked. I sold the boat to a friend and he is still using it. My skeeter bass boat came with an on board 3 bank pro charger. If it didn't I'd buy 3 of these at 20 $ a piece.  Instead of the few hundred for the single pro charger. Shumacher needs to make this same charger with 3 banks for 60$ and I'll buy it. I know all my friends who are anglers would do the same!