Almot wrote:
Yes, there are AGM starter batteries. Optima Yellow (?), Odyssey, and probably a bunch of less known Chinese knockoffs. The performance varies a lot.
Yep. The big AGM difference is between the spiral wound like Optima and the rectangular ones.
We need to set the spiral wound aside as a special case as they are special purpose and normally not the best choice for RVing.
That leaves the rectangular AGMs which come it two usage categories, starting and dual purpose. Some have more CCA or more AH, but all have both AH and CCA.
E.g., a Deka 8a24m has 79AH and 470CCA and a Sears P-4 has 68AH and 850CCA and both are 53lbs. Obviously, the first is primarily for deep cycle service and the second for starting.
6V AGMs are not significantly different than their 12V cousins. There is no real advantage to 6V AGMs on an AH or CCA specs comparison.
HTH;
John