" wrote in news:d58baedd-dd67-
:

On Jul 19, 5:22*pm, Brian Whatcott wrote:
..
Still, give a person credit for gun-shyness from a battery fast-
charge
accident! ...

Oh yes. An exploding battery while offshore is a nightmare! I
appreciate the concern. I think Larry is incorrect in his assertion,
but I'm listening because if he convinces me that he isn't then I'm
going to change my ways fast.

-- Tom



I heard a noise about taking the VOLTAGE REGULATOR off the alternator
and putting a manual current control on the field winding so it can be
"cranked up" to whatever charging current some idiot wants. Look back,
I forgot who said it. This is the absolute stupidest idea I've seen
about battery charging. I know why they are doing it. they've been
watching that ammeter that starts out charging like hell for the first
few minutes, then DROPPING LIKE A ROCK as the surface of the plates
becomes replated and the ions in the near-plate electrolyte are used up.
Right there at the surface of the plates, in the worst possible place,
there's a tiny slice of battery that has already charged. When more and
more current is shoved through it, by cranking up the charging (voltage
is the ONLY way to overcharge ANY lead-acid battery) that little slice
turns current directly into heat, gassifying the water at the barrier
into O2 and H2 and heating those plates!

I'm in FULL AGREEMENT of 14.2 to 14.8V REGULATED VOLTAGE charging....the
way the damned alternator was delivered. BUT, alas, this will NOT
recharge those batteries in an hour! The voltage rises very quickly up
to over 14V to the regulation point because the charge right there on
the surface causes the cell voltage to rise quickly as it runs out of
free ions to convert until more MIGRATE....SLOWLY....IN HOURS....to
replace the ones the initial current shock used up so quickly at high
current.

The boater, of course, with his eye glued to the AMMETER sees the
charging voltage max out the regulator and that LIFE THREATENING CURRENT
DROP happen so quickly, coming off the current limit of the alternator's
winding resistance and field strength. THAT BATTERY IS NOT CHARGED! If
you PROPERLY measured its specific gravity, you'd see the electrolyte
gravity hadn't moved hardly at all. Of course, in the wonderful AGM
battery you cannot MEASURE the specific gravity of the soaked up gauze
electrolyte so you have no idea of its charge condition.

Just because the voltage went up and the current went down DOESN'T MEAN
THIS BATTERY HAS CHARGED! It means this battery is in the process of
charging and has caused the charging current to drop back to a SAFER,
more sane level...tapering off because of the VOLTAGE REGULATOR, not the
charging level, to a long-term, plate-soaking true charge that soaks
INTO the plates....not plated upon its surface.

Battery charging takes 14 hours......REALLY! You cannot get 90% from
50% using a NORMAL, voltage regulated alternator in 60
minutes...CHEMISTRY won't allow it.

This will soon change as we leave these 1885-era chemical monstrosities
behind us. A fantastic technology is coming. You charge it at a
thousand times its AH rating for SIXTY SECONDS to 80% charge and 3
minutes to 100%! Read he
http://www.physorg.com/news3539.html

Your problem with the new battery is providing it the 8000A to recharge
it in a minute from your measily 55KW diesel aux engine....NOONE will be
overcharging this puppy!