"Mark" wrote in news:1156829173.178462.265980
@h48g2000cwc.googlegroups.com:

From a University of Washington paper:

"If plates are exposed above the electrolyte then the capacity of the
exposed plate
areas has been lost and cells will likely develop short-circuits
because of plate shedding. Batteries with exposed plates should be
replaced."

You seem to be saying exposed plate area can be recovered by
recharging. That's apparently not so. I once accidently exposed about
50% of the plate area on a battery, and it lost about 50% of its
capacity; soon thereafter it died due to shorted plates, probably from
plate shedding. Exactly as the UW paper described.



In order to "sulphate", conversion of lead metal into lead sulphate, it
takes sulphuric acid, not air. Lead sulphate is suspended in the
solution of the electrolyte, after it has released its electrons to us.
I don't see how exposing lead to air can eat it away. That's what the
posts are doing all the time, and they're lead.

No, I disagree with the professors, I'm afraid. Using a battery with low
electrolyte eats away the BOTTOM of the plates, sometimes bad enough to
eat holes in them we cannot recover because the electrolyte still has the
same acid it started out with, in a more concentrated form, and the
electronics freed must come from the plates still submerged, eating them
away far worse than the engineers intended. So, if anything is
"damaged" or "unrecoverable" it MIGHT be the submerged portion of the
plates, not the exposed-to-air top, which won't get eaten away
discharging at all. See my point?

It's the submerged part that needs to be recharged very badly, not the
exposed part. But, alas, we're talking of extreme conditions, not the
conditions in your boat. You don't discharge the battery severely, or I
hope you don't. You also didn't let the battery get THAT FAR down in
electrolyte, just a little below the plates, exposing them. When you
submerge these plates, that haven't been holed permanently, with
DISTILLED WATER ONLY, please....The battery will nicely recover, after a
few charge/discharge cycles, to its soft plated old self, the tops of the
plates resoftening by the cycling, like we're SUPPOSED to do to a brand
new battery that's just had its initial electrolyte charge poured into
it. Of course, noone in reality ever does a proper cycling of a new
battery to soften up those plates. That takes too much time from our
busy life. The dealer doesn't do it, either. He pours the electrolyte
pack into the holes, helter skelter, and never checks the gravity again
to see which cells are really hot and which are not-so-hot...caused by
differences and impurities in the plates.

If we had any brains, we'd dump this crap and go back to "Edison Cells",
those Nickel-Iron-Potassium Hydroxide beasts just outside my hamshack.
Mine were made in the late 40's for a telephone system and STILL have the
capacity stamped into the cases....(c; Ni-Fe batteries are only bad for
the battery business....never needing constant replacing and recycling as
Pb's do....the reason they just HAD to be eliminated.
http://www.beutilityfree.com/battery...tery_flyer.pdf
Don't worry about how deep you discharge them. Recharge them when the
lights get too dim...(c; It doesn't hurt them at all. You don't even
need a regulated charger.

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

"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.

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

Have you actually done that? 1.5 amp charger charging a 500AH bank or
larger.

I'm guessing a 500AH bank would need at least a 5 amp charger to bring
it up to 14.2 volts and a fully charged state. A 1.5 amp charger might
bring it up to something like 80% charged before it can't up the
voltage above 13.2 volts or so, and just floats the partially charged
bank. Could be wrong though, anybody wanna chime in here with
firsthand experience?

I do agree a 1.5 amp charger will float a fully charged 500AH bank,
that's 36 amps a day, more than the natural discharge loss of the bank.
But will it charge it up from a deeply discharged state?


No, actually it was only 330AH of golf cart 16H batteries.

All this is quite moot on a "working boat" sitting in a slip. The 1.5A
charger is NEVER going to recharge or even keep charged a boat that has
LOADS running all the time, like bilge pumps cycling on and off to keep
the dripping packing glands from flooding it. I don't recommend it for
that.

What I DO recommend the little brick for is any boat that's shut off
sitting on a trailer or in a dry stack or put up for the winter. The
battery is disconnected from all loads and only needs a VERY slow
recharge, like my little brick creates, over long storage periods, longer
than a week.

It's not for charging the boat battery at the slip between uses. What IS
really nice about it is you can go off for 3 months and come back to
batteries that are REALLY hotly charged, so slowly, and NOT have to add
water to them, at all! Charging this slow rarely makes a bubble of
hydrogen. I've never seen electrolyte drop at all from the 75AH deep
cycle driving my dink's electric outboard to the 330AH beasts in my shop.

At $30 a charger, if you have two banks of house batteries, use two
little bricks, not one, on separated battery banks, eliminating the
cross-discharging that always goes on in parallel. (You won't hurt them
if you screw up and put them in parallel...been there, done that. Then,
you'd have a 3A, stepped-charge charger as one of them will always have a
little different trip point than the other, shutting one down first.

This morning, the 1.5A brick charger is recharging some utility gelcells
for me....from 2.2AH to 12AH...I have laying around the shop. When it
starts charging a small 12V gelcell like these, the "charged" LED
immediately comes on after 5-10 seconds, and starts blinking on and off
as 1.5A is WAY too much charging current for a 2.2AH gelcell. The "on
time" (when the LED is off) and the "off time" (when the LED is on)
exchange time lengths as the little batteries charge up. Eventually, the
LED stays on for many minutes and occasionally winks off, immediately
coming back on because the little battery is fully charged. It's easy to
see when the charge cycle is completed, and forgetting it for a day seems
to make no difference at all.

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

Daniele Fua wrote in news:J8VIg.85744$zy5.1465697
@twister1.libero.it:
a "smart" regulator would fit. I understand that there should be a way
to cheat the regulator and force a higher charge for at least some
reasonable time. Anybody knows how?

Don't! You cannot get a good charge on any lead-acid battery by heaving
great gobs of current to it for 10 minutes. You get what's known as a
"surface charge", a quick, but useless conversion on the surface of the
plates that goes away, as you have obviously discovered, very quickly.

Batteries must be charged SLOOOOOWWWLLLYYY to get a good charge, the
slower the better. That 20A you're getting is the battery's chemistry
resisting having its guts heaved out by the 14V applied...and is NORMAL
AND DESIRABLE as it reduces charging time to something, while not ideal,
at least a little more reasonable. A good charge happens at 10% of
capacity...20A on a 200AH battery. The chemical reaction of our archaic
lead-acid batteries just happens slowly recharging. Don't go screwing
around trying to overhead and warp the plates on them in 10 minutes.
Next time someone has a battery explode on their boat, wait 4 days then
go look at what that looks like and you'll very quickly PUT THIS NOTION
OUT OF YOUR MIND!...(C;

However, just over the horizon of battery technology is just what all
boaters are looking for....INSTANT CHARGING BATTERIES are HERE! Look at:
http://www.physorg.com/news3539.html
http://www.technewsworld.com/story/hardware/41889.html

http://www.worldchanging.com/archives/002435.html
"The excellent recharging characteristics of new battery are not its only
performance advantages. The battery has a long life cycle, losing only 1%
of capacity after 1,000 cycles of discharging and recharging, and can
operate at very low temperatures. At minus 40 degrees centigrade, the
battery can discharge 80% of its capacity, against 100% in an ambient
temperature of 25 degree centigrade)."

Even Yankees freeze solid at -40C!

These Li-Ion batteries will be in hybrid and electric cars very soon. In
a boat the DENSITY of the technology is going to be MOST welcome! The
capacity of your huge battery bank will be reduced to the size of a loaf
of bread with HUGE conductors attached to it so we can charge it at 400A
or 4000A or more! THEN, your charger is going to be the issue....too
small....little diesel. The entire output power of your Perkins 4-108
COULD, with this new battery, be converted to charging current...AND THE
BATTERY WILL ABSORB IT AND CHARGE IN MINUTES, NOT HOURS.

In vehicles, dynamic braking, which is currently too much power in too
short a time to be of much use, will store most all the energy of braking
right back into the battery bank to be used to boost you away from the
traffic light, to the amazement of that little ******* with the noisy
Honda who always goes shooting off ahead of you, now.

Back to the calculator.....

Let's say we're going to get 400AH of "house battery" in the new
technology. 3 minutes, to fully charge it to 100%, is .05 hours. So, if
we're going to charge a 400AH/12V nanoLithium in 3 minutes, we're gonna
need:
400AH divided by .05 = 8000 AMPS for 3 minutes! Boy, that's gonna put a
sweat on those v-belts...(c; 8000 AMPS! Hmm...746 watts = 1 hp, give or
take a little. 8000A at 14V = 112,000 watts divided by 746 = 150 HP
(plus any inefficiency of the charging system, of course.) We're gonna
need a bigger ENGINE...not to mention alternator!

When this technology emerges, I hope the boat business will have enough
brains to switch to diesel-electric, traction motor drives. You'll have
that 100KW electric power plant....well, maybe 50hp, 1/3 of that....and
will be able to charge the new battery bank in 10 minutes at FULL POWER
or switch the electrics to the traction motors for propulsion (and bow
thruster??)....(c;


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

As you suggested Larry I was able to get the totally dead battery to
take a charge using an old fashioned, not fully automatic charger.
Thanks for the suggestion!

Also, I picked up one of those 1.5A bricks you suggested. The one I
found was a Schumacher Model WM-1562A. About $15. Similar to the one
you suggested except it's rectangular, and has a 6/12V switch. The
switch is useless to me, but oh well. All the other features are
exactly as you mentioned.
Thanks again!

(Floating Mind) wrote in news:4579-44FDAD37-284
@storefull-3111.bay.webtv.net:

As you suggested Larry I was able to get the totally dead battery to
take a charge using an old fashioned, not fully automatic charger.
Thanks for the suggestion!

Great! Works quite often. I wonder how many recoverable batteries got
trashed because of the computerized battery chargers....and what the
motivation is making them the way they are.....sales?

Also, I picked up one of those 1.5A bricks you suggested. The one I
found was a Schumacher Model WM-1562A. About $15. Similar to the one
you suggested except it's rectangular, and has a 6/12V switch. The
switch is useless to me, but oh well. All the other features are
exactly as you mentioned.
Thanks again!



I found it on Ebay. The dealer wanted $42 so you did well...(c;

It's much larger than mine....but does the same thing.

Glad it worked out for you. Hope the battery will stay up WITHOUT the
charger hooked to it, now. Leave the battery sitting without the charger
for a full week then let's see if it will take a load like it should.
That'll be the key...




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