6V vs. 12V Ah equal?

I see the 20 hour rate used on most batteries, but there are a few sneaky exceptions. 6's often have more amp hours than typical 12's at very low draws for the same 20 hour amp hour rating, and of course conversely less inverter time and fewer amp hours at higher current. It really depends how you are going to use them. Thick plates win for cycles and slow draws, thin plates with lots of surface area win for high current. Get lots and lots of either and you can do about anything because they are hardly working hard. But good luck recharging!

Jim