A friend of mine says
Before spending mucho denaro try to evaluate your needs based on cruisingstyle.I have used two GNB golf cart (GC-2) batteries for the last eight year.They are generic GC-2, lead acid, 6v, 220 amp-hour reserve @ 70 amp drawbatteries. I've been out for 4 days with family and continuous cabin hotel& instrument loads without charging and still had 55% capacity.These are big, heavy duty batteries.They are wired in series (12v) and make a great house bank. I don't have astarting bank (outboard is hand crank)They have served me well and are VERY cost effective ($30 @ Sams in 1996),but do require continuos monitoring and diligence.