"Roger Long" wrote in news:wxI0h.11440$0L1.9288
@twister.nyroc.rr.com:

These two year old batteries get pretty light use with a
15 hp diesel, a few lights, and frequent dockside charging from shore
power. I don't leave the charger on all the time so they don't micro
cycle but they seldom get pulled down very far either.



I don't advocate constant charging on batteries that are stored. I
recommend a SIMPLE automatic shutoff charger put on them overnight ONCE a
month during the storage period, with the batteries completely disconnected
so there's little external leakage over the dead period...just disconnect
their terminals. ONE a month, not a continuous trickle which usually
results in them gassing with a little overcharging, no matter how much a
boat dealer charged for the chargers...(c;

As to pulling them.....they should be stored ABOVE 0C, so there's no
possiblity of them freezing, even if discharged inadvertently. AGMs and
gelcells have no place to expand to all wadded up like they are so anything
the might freeze them will simply destroy them. If the boat's going to sit
on the hard with no internal heat in -20F winter...pull 'em.

Another factor might be a self-preservation issue. Batteries are always
subject to internal shorting...and subsequent explosions. If anything
warps a plate...like really cold weather...a simple plate-plate short will
blow the thing apart, turning the acid electrolyte into a steam explosion,
distributed evenly over everything left in the boat.

You have to weigh that $70 against this Worst Case Scenario....It's your
call...(c;

(If you ever get a chance to look around in a boat the battery exploded
inside of, please take the time to look around. It never ceases to amaze
me how it can etch a fork buried in a tightly closed drawer on the other
end of the boat from that battery!)

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