I'd say there are 2 problems with doing this. First one is that although I couldn't find the manufacturers rated amp output, I can't imagine it being enough to make much of a difference in the grand scheme of things. I did see in the "outdoor answers" about this item that 2 users responded to a question about it's output. One claimed 300ma, the other said he was getting 1.5amp (I have doubts about this claim). Even if you wanted to be optimistic about it and say the output is 1.5 amp, that's the output of a float/maintenance charger and not enough to try to charge a deep cycle with. The other "potential" problem, would be if you forgot to disconnect this from your battery and it stayed on for a prolonged time. Once the battery was at full charge, it would have the same affect as leaving a trickle charger on without the benefit of a maintenance/float control circuit. And that could harm your battery. But that's just my opinion so if you decide to try this, let us know how it works out for you.
