60stradewin,
I bought my Solargizer off ebay. I really like this model because it has more than a charger/maintainer built into it. It has a desulfation mode that sends pulses to the battery plates to help shake them of deposited material so that it will dissolve back into the battery acid solution. Do an engine search for Solargizer battery chargers and you should hit their website. There have been times that I felt that more is better i.e. maybe another 5 watt panel attached to the other battery or maybe a 10 watt version of the Solargizer. The 5 watt has worked for me so far. Unisolar has flexible solar panels which fit curves of boats, etc. Camping World, Northern Hydraulic and numerous other sites sell the ICB Global (I think that is correct) solar systems ranging from an auto battery maintainer to 100 watt panels with 21 amp controllers. I talked a friend into the 5 watt ICB that was on sale for $69 and he has been happy with it. He though it had failed after leaving the trailer for several days. He found that he turned his gas system off but left the electric fan system on. When the temps got down, the fan ran all the time and the poor battery never could catch up. He took the battery home, charged it up and it has been fine since. Lucky him.
Also check
www.rvsolarelectric.com for good info on solar systems and a great catalog.