The Quick Cable 303303 Quick Power Battery Isolator is rated for up to 120 Amp alternators. This unit allows you to charge an auxillary battery withing a vehicle, boat, or RV. This fully automatic switch allows for your engine alternator or aux battery charger to charge 2 batteries, while keeping the batteries electrically isolated from each other. This means that you can run your spare battery down, without worry of running down your starting battery.
This waterproof unit will work in a marine environment, as well as stand up to extreme heat. The Battery Isolator switch will prevent current flow from one battery to another, thus allowing each battery to be an independent power sourceMake sure your batteries are of same design. If battery types are mixed, you may damage one or both.