Ive got about the same issue going on. My current set up is what came with the boat. The bank is made up of 2 deep cycle marine batteries and a starting battery that was for the motor. There is no real charger in the system, just a AC-to-DC converter. In the year ive had the boat, the bank has always stayed charged up and will run my load for about 2 days before dieing. Now since we will be heading out to anchor soon, im going to put off buying a charger and just geting my Air-X wind gen going. Ive got 4 golf cart batteries to use for my bank. I know the Air-X isnt going to keep the bank fully charged since ive got 3 large 12v(house style bulbs) lights to light the boat and a small TV that runs on 12v(love that since our marina is the main target of power outages). Ive got a 700watt Kawasaki generator that i can use to help keep the bank up. The boat did come with an older car battery charger that ive used before to get the bank in shape before going out for a trip. It works decent, but is junk, its about to rust apart.