This page should help anyone to manage the current drawn on the batteries:
http://rveducation101.com/articles/RVConverters.pdf
...and I think it was Jamie wondering about how batteries might work in extreme cold. I understand the average flooded cell type battery would freeze and not work. I believe there are types of batteries that will work in the cold, but they might be cost prohibitive, depending on your budget.
I'm looking forward to the day I can afford two big solar panels, inverter, and four, count 'em, four 6v deep cycles. I'll have to bolster up my battery tray to take the weight. Not enough left in my hunting budget to do it this year.