http://it.aminet.net/pub/electronics/REPAIR/F_audiofaq7.html
...
2. Battery - deteriorated or abused lead acid batteries are very common.
   If the battery will not charge or hold a charge, battery problems are
   likely.  A UPS (or any kind of lead-acid battery powered equipment)
that
   lies idle for a long time (say a year or two) without power to top
off
   the battery will likely result in a dead - not salvageable - battery
due
   to sulfation.  Symptoms will be: voltage on battery climbs to more
than
   2.5 V per cell when first put on charge and even after a long
charging
   period, the battery has essentially no capacity.  If the battery
voltage
   is at its nominal value - even when the inverter should be running
from it
   (and there is no or low output), then there is a problem in the
inverter
   or its connections or there is excess load.

Something on reversing sulfation. Use at your own risk.
http://www.allegromicro.com/techpub2/cadex/index331.htm

And then there's the 'bogus' stuff
http://www.webcasting.com/pulse/leadbat.htm
"As the sulfate crystal resonates, it is able to become ionized and
reform back into the electrolyte and active material."

Uh huh. Sure. And the resonate frequency of these crystals is??
Ionized by resonance? Tell me more...

"This gentle pulse (150 millivolts 80
milliamps under load), is harmless to the battery and charger. "

150mV is going to do bugger all WRT the electrochemistry of the cell.
I wonder they using a PIC in the controller <G>.


Robert Rolf wrote:
>
> It's called SULFATION. Permanent and fatal, and the number one cause of
> lead acid battery failure. (number 2 is plate shorts from shedding).
>
> The battery was left in a discharged state for too long (many weeks)
> and the lead pentoxide on the plates was converted to lead sulfide
> (which is very inert).
> The sulfation process is not easily reversed although some references
> suggest that charging at 1/100C can undo the damage. I have tried
> this on numerous batteries (mostly UPS's that weren't turned off
> correctly), without success. There are also a number of products
> that claim that they can 'fix sulfation' but I rather doubt their
> efficacy, given the tenacity of the chemical bonding that occurs.
>
> If this were a commercial battery I would return the battery to the
> supplier with a strongly worded letter of complaint about their poor
> storage practices and sale of 'dated' batteries. Since this was a
> 'friend' you have to tell him that he sold you a bad battery because it
> had been left uncharged for too long. You thought you were buying a
> 'good' battery. It wasn't, so your friend should make-good on the deal.
> If he sold you a case of beer and it was sour, would he replace it?
>
> James Cameron wrote:
> >
> > Bought a new 6V 5AH sealed lead acid battery, and when it arrived it
> > had no apparent capacity.  Not quite as dead as an open circuit,
> > though.  It seems that applying a constant current charge simply
> > results in the terminal voltage soaring to whatever voltage limit my
> > charger has.  Remove that and the voltage via DMM drops to 1.3V.
> > Battery is dated in 1999 some time.
> >
> > Is this a "normal" behaviour, and is it fixable?  Any references?
> >
> > Or is it a "return"?  [bought it via a friend; problematic]
> >
> > --
> > James Cameron    mailto:quozl@us.netrek.org     http://quozl.netrek.org/
>
> --
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