"Mark" wrote in news:1156831412.903466.125420
@b28g2000cwb.googlegroups.com:

Sulfation which drops to the bottom of the battery case does not
decrease battery capacity. There's space at the bottom of the battery
for just that reason. The battery's service life is decreased;
ultimately enough crud will drop to the bottom of the battery to short
it out.



This is just not true because the capacity of a lead-acid battery is
caused by the acid charge in that battery. "Discharged" means, quite
simply, that we've run out of acid to eat the lead. Lead Sulphate that
drops out of suspension and cannot be recovered from the bottom of the
battery USES UP the acid charge, making that acid charge unrecoverable.
As it sulphates (or sulfates, I gotta go look that up some time) more and
more the "fully charged" specific gravity, the measure of the acid
intensity in the electrolyte, will fail to come up to 1.260-1.280 of a
new battery. The sulfated (sulphated??) battery will run OUT of acid on
discharge faster. You've lost capacity.

"Dead Cell" isn't really dead. It's just that its acid load has been
converted "mostly" to lead sulfate and can no longer be charged.

Now, before we get to the plates-have-been-holed-and-warped state, you
can ADJUST the acid load on a FULLY CHARGED battery back up to recover
the lost acid to sulfation. VERY SLOWLY adding sulphuric acid to the
electrolyte, agitating or simply waiting for a day, then adding more as
you continue to test specific gravity with your TEMPERATURE COMPENSATED
real hydrometer, can recover a low capacity cell you haven't let go too
far. (This sorta happens when some IDIOT drops an aspirin tablet, 2-
(acetyloxy)benzoic acid, into the poor battery he's trying to destroy.)
He gets a momentary boost in voltage and thinks he's fixed it. He
hasn't.

It's this sulfation problem of lead acid batteries the manufacturers
depend on to produce a steady stream of sales to the same people, over
and over. Sales have gone up since we convinced them a gelcell or AGM
battery that CANNOT precipitate its crystals is worth $300. When these
stationary-electrolyte batteries sulfate, the sulfate crystals stay in
place. Of course, great for manufacturers, there isn't going to be any
smartass adjusting the gravity to save it if we seal it all up and make
it "maintenance free", now, is there?

--
There's amazing intelligence in the Universe.
You can tell because none of them ever called Earth.