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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