Larry wrote:
"Roger Long" wrote in news%11h.492$xw1.375
@twister.nyroc.rr.com:


I understand that the AGM cells in my boat are a wrapped sandwich of
glass mat and the lead plates. How can contact between these plates
be very likely? Is the boat just sitting there motionless more
likely to have these well supported plates bend than all those cars
sitting in unheated garages and out on the street? First, the
batteries have to discharge which seems pretty unlikely with the
cables disconnected. My wife has to have AAA jump start her car a
half dozen times a winter because she doesn't close the doors all the
way or leaves the lights on. No problem so far.



Oh, the cars have their share of battery explosions, usually from the
unfused alternator diodes shorting to ground or the frozen starter with
the shorted commutator. However, it's not much of a mess in a car where
the acid bath is so easily washed away as soon as it happens, and is,
mostly, forgotten, unless it exploded when the WIFE turned the key,
which, of course, is all YOUR fault. The batteries, usually, don't short
internally plate-to-plate because of the separator....as long as they
don't get hot when the supercharger screws up and puts 40A to them for a
couple of weeks while you're ashore or the boat alternator diodes that
ALWAYS have DC voltage on them with the key off, short same as the car.

I had a red AGM battery that came with my government-surplus Chevy diesel
stepvan "go off", by the way. That was an internal short. It didn't
explode, I suppose because the short wasn't a dead short. It simply
MELTED as the plates became so hot it blew the safety pressure valves out
of it and boiled the electrolyte in the gauze into steaming sulfuric
acid. The cell that shorted, took out all the other cells because it
melted from its cylinder into their cylinders. I swapped it with an AGM
dealer who gave me a nice credit against another AGM battery priced like
a Lexus front end. Luckily, the one that melted opened from post to post
so it didn't also short the other one in parallel with it used to crank
the 6.2L diesel V-8...which now runs on free frying oil from 3 chinese
restaurants...(c; (www.frybrid.com)

Larry
You ARE paying the state and federal road tax aren't you?