Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!boulder!sunybcs!kitty!larry
From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: sci.electronics
Subject: Re: Recovering Lead Acid batteries. (Gel. Cells)
Summary: Not a good idea...
Keywords: Gel Cells Lead Acid
Message-ID: <3113@kitty.UUCP>
Date: 23 Apr 89 15:38:11 GMT
References: <2225@letni.LawNet.Com>
Organization: Recognition Research Corp., Clarence, NY
Lines: 33

In article <2225@letni.LawNet.Com>, doug@letni.LawNet.Com (Doug Davis) writes:
> My problem lies in the batteries that it uses are Gel Cells which
> a couple of them will only hold a partial charge.  But they do hold a
> charge. Two of them hold about 2/3rds normal voltage, and 2 more about
> half and one barely holds a volt. These are 6v gel cells.  My question
> is, is there any way, like shocking NiCads, to recover full capacity
> of these gel cells.

	A common failure mode of gel cells is loss of electrolyte through
overcharging and/or cracking of the case due to age and/or heating effects.
This is most likely the cause of your difficulty

	There is no way to "shock" a lead-acid battery into effective
operation.  The only real option deals with correcting the condition of the
electrolyte.  Since gel cells are not designed for the user to gain access
to the electrolyte, there is no effective way to do this.  Furthermore,
since gel cells use an electrolyte that is gelled using a thixotropic
material such as methylcellulose, adding water to an existing gel without
possibility of mechanical mixing is not practicable.  There is no ready
source for obtaining already gelled electrolyte - and even if same were
available, this would not correct a low water condition.

	I have heard of a few intrepid souls who have opened sick gel cells
and have diddled with the electrolyte, sometimes with a partial success.
However, I would strongly discourage such efforts.  Safety factors
notwsithstanding, the biggest concern would be the case cracking open
due to stress or improper re-resealing, thereby allowing electrolyte to
spill and damage apparatus.

<>  Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp.
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