"Roger Long" wrote in news:2GAQf.7687$Zs1.7219
@twister.nyroc.rr.com:

When running for long periods under power
however, my expensive AGM's are being driven by the alternator which
isn't significantly different from the ones on the Model T.
Retrofitting my larger spare with an expensive, 3 stage, temperature
compensated regulator is on my wish list.


Like most boaters who've been sold amazingly overpriced AGM batteries,
you've been duped into thinking they are some amazingly different
technology than the cheap $89 golf cart batteries from Sam's Club.

The AGM battery is not. It's simply a cheaper way of rolling up thin lead
plates with glass mats soaked in the same electrolyte used in all the other
lead-acid batteries. These plates cannot be as thick as the ones in the
golf cart batteries because the big thick plates are very hard to bend.
With so limited an amount of electrolyte, that cannot flow in the gauze and
cool the cell while moving fresh acid in contact with the plates as the
solution of lead sulphate moves away, it matters little how thin the plates
are. To get capacity, the plates rolled up are huge!

BOTH these archaic lead-acid batteries are charged just fine with any
standard alternator with a voltage regulator. They've been working fine
since way before the Model T was produced....(c;