The AGM batteries will thrive if you only drain them 50-75% and then recharge them.
This practice alone will add many more useful charging cycles over the life of the battery as compared to nearly depleted each use.
Therefore if you purchase two group 31's with each about 100 amp hours.
And say you run the terrova nonstop for 5 hours at about mid speed or less
that would be somewhere near 20 amps an hour usage times five hours.
The two batteries in a series would have supplied about 100 amp hours therefore about 50% of their charge, i do not have the amp hour usage chart of the terrova in hand therefore my figures are only estimates, maybe someone can chime in.
btw: i had seen three one year old blue top optima batteries being sold on another forum IDO, if you are in MN they may be a deal, they where group 31M three for $100 each or +20 if you did not purchase all.
I have not used that brand, i read both positive and negative feedback, yet at $100 and they still should be covered by the 24 month 100% replacement warranty.
Last edited by cyber16; 04-13-2012 at 11:26 AM.