There is also the possibility of the new Firefly Group 31 batteries. Their specs say they are good for 700-800 recharges at 80-100% Depth of Discharge. Standard deep cycles are good for 200-300 charges at these dod's. Haven't seen a cost on these yet. I expected the weight to be less based on early information by Firefly but I see the batteries are weighing in at about 70 pounds each. Not too different than a standard deep cycle. Here's a link to the spec sheet.
http://www.fireflyenergy.com/images/...t%20012308.pdf
JJ