You can get quality 12v deep cycle batteries with capacity similar to the 6v golf cart batteries. For example, a Group 27 12v deep cycle from Trojan, the model 27TMH battery, produces 115 amp-hours, so a pair is 230, just like a pair of 6v golf cart deep cycles. The slightly larger group 30 Trojan 30XH produces 130 AH each, for a total of 260. These are true deep cycles, not marine hybrids.
However, the Trojan 12v's will probably cost you more than the 6v golf cart batteries, so it may be worthwhile to re-wire for 6v series operation.
2004 American Tradition; 2014 Buick LaCRosse
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