The battery that came with my travel trailer THE battery?

Amp hrs are the same 6v or 12v, if we talk group 27 12v, verses the std golf car 6v. Either will work fine. If it were me, I'd go w/ the 6'ers, but don't really know why (please don't tell me why I should or shouldn't) I used 6'ers for 9 yrs, now I'm using 12'ers, and w/o getting all tech'y there ain't no difference, no matter what !!.
But I do like the series connection on the 6'ers a little better

FYI, the 6v batteries are the same size as group 24 12v, except they are at least 1.5 inches taller