Morningstar Sunguard 4.5A 12V Solar Charge Controller - Waterproof MPPT Battery Regulator for Outdoor Solar Panels | Low Failure Rate | Perfect for RV, Boat, Cabin & Off-Grid Power Systems

I've been using these for years to charge 12v deep cycle batteries with solar. They work great in the north florida sun and humidity. Out of about 35 of them I've only had a few fail over the years. Slightly expensive but far better than the cheaper solid state charge controllers.