Way to revive tired gel-cell batteries?

[JakeD]

I have acquired some 12v gel cell batteries, some of which have been
left in an almost discharged state for several months, and don't seeem
to be charging up readily. I vaguely remember hearing some tips on how
to breath new life back into such batteries. I think the advice was to
charge rapidly, then completely discharge quickly, and repeat several
times. And another trick I think I heard was to put the battery
charger leads on the wrong terminals momentarily. I vaguley remember
that this was supposed to blast something or other off the plates.
Does any of this sound plausible?

Thank you,

JD

 

[Ecnerwal]

In article <akirr3h23vmft8epcm81kckbhd9tcd8dfn@4ax.com>,
JakeD <JakeD@n3ddfdfdf2223n.com> wrote:

I have acquired some 12v gel cell batteries, some of which have been
left in an almost discharged state for several months, and don't seeem
to be charging up readily. I vaguely remember hearing some tips on how
to breath new life back into such batteries. I think the advice was to
charge rapidly, then completely discharge quickly, and repeat several
times. And another trick I think I heard was to put the battery
charger leads on the wrong terminals momentarily. I vaguley remember
that this was supposed to blast something or other off the plates.
Does any of this sound plausible?

Not for lead-acid gel cells. IMHO you may be scrod with abused
gel-cells. Here's some info from a place that deals with a lot of
batteries.

http://www.windsun.com/Batteries/Battery_FAQ.htm#Gelled%20electrolyte

You might (and might not) get some benefit out of using a desulphator on
them. Can be bought or built. More typically useful on liquid acid
batteries, but possibly worth a shot - on the other hand, you can get
"good used" batteries for not a lot of money, e.g. from
www.allelectronics.com (not even a customer, but have them in my list of
places that have stuff I've looked at - notably, fixed low shipping,
which counts for a lot when ordering heavy batteries).

The original article now seems to be on a pay to view basis, but here's
a derivative article:

http://www.geocities.com/yosemite/2358/e_electrical_tips/e04.html

For nicads, "zapping" them with a big capacitor can be beneficial to
blow off dendrites that form and short out the plates. Does not restore
full capacity, but can restore some useful capacity to cells that had
reached uselessness - ie, won't take a charge at all - zap, get perhaps
1/2 original capacity. I've done that repeatedly with some drill
batteries. Always in correct polarity - I can't see any benefit to
reverse - sometimes abused cells reverse, but that's NOT a good thing.

--
Cats, coffee, chocolate...vices to live by

 

[JakeD]

On Thu, 21 Feb 2008 21:55:55 GMT, Ecnerwal
<LawrenceSMITH@SOuthernVERmont.NyET> wrote:

Not for lead-acid gel cells. IMHO you may be scrod with abused
gel-cells. Here's some info from a place that deals with a lot of
batteries.

http://www.windsun.com/Batteries/Battery_FAQ.htm#Gelled%20electrolyte

You might (and might not) get some benefit out of using a desulphator on
them.

Thank you very much for the links and suggestions. Extremely helpful -
many thanks...

JD