I agree completely Denny. I once had a 52' GMC 2 ton size that somebody had put an 8V battery in. It was a good battery but wouldn't take enough of a charge from the 6V generator to keep it up. A new 6V battery was installed and everything was great after that. Mismatching parts, especially electrical, is not a good idea IMHO.
Incidentally my 8V battery was a Delco Marine battery.
