Let me throw this out there,, went from two deep cycle interstate 12v group 27's to two Costco 6V 220 AH golf cart batteries,, maybe three years old,, not allot of use because we boondock 60 % of the time and only for five days max,, Lately have been only out three times this year and batteries have been home on a Schuamker battery tender for two months at a time and a month off, They never fell below 12.7,, I am headed to the coast tomorrow for three days, tested the heater because temps might drop into the high thirties,, not freezing, heater drew the batts down to 12.1 before I shut it off, and recovered at 12.3, When I hooked them up they were 13.4, Not happy!! water level was topped off (just below the ring)and I have 200 watts of solar, I will bring along my group 31 trolling motor Wal Mart battery just in case!! I am leaning towards a set of Trojan T105s if these don't cut it. My thought is the heater will cut in a few times while we sleep, I have a Gen and will charge daily, I have never seen these deplete so quickly,, If they **** out next week, Its off to High dollar quality, if that does not work,, back to 12v Optima's!!
Had one on my PUP (Yellow Top) Couldn't kill it!!