I thought about going to dual batteries, but on one of the boards I was on at the time

There was a realy good discussion going on about the pros and cons of single vs dual batterys.
In a nut shell,
A single battery may drain quicker but it also can be charged quicker.
So in the long run if you go with two, you might be left with two dead batterys needing a long time to charge.
Anyway it was a long discussion and it convinced me to go with one battery and I'm planing on going with a higher output altenator.
P.S. Another thing to do if your wenching, besides sutting off all electrical draws, is to put in something like a hand throttle where you can raise your RPMs up to 2000. Your altimator will charge at peak outtput then, it can't at an idle.