I too do not think it makes much difference so long as all 4 batteries are good but.. IF one battery dies.. Well. the Put 'em in series tHEN parallel works better I think.
I'm fond of saying there are no six volt batteries in RV's.. This is because when you take two IDENTICAL 6 volt GC-2's and put 'em in series they "Magically" (No magic about it) become one big 12 volt battery.
You then parallel as many 12 volt batteries as you can carry.
So why not just put in a 4D (12 volt 220 amp hour).. WEIGHT. Those suckers are HEAVY!!!!!!!
