"Aren't dead Pb batteries dead forever ?"

Lead-Acid batteries or gel-cells?

Lead-Acids, when dead, don't conduct and then something
in excess of the 'normal' is required to begin the process
of getting something back into 'the water' ... I've seen
this more than just a few times in my life, and, no, it's
not good for the battery ...

The times I've done this the battery was 'killed' over-
night by the *usual* means!

Jim

PS. I have used the "crudely pulsed high current"
technique before - I found I get the best results (and
only use the) 'Cap Method' nowadays using my specially
set-up 76,000 uF 40 V "Srague Powerlytic" whose sole
duty in life now is to zap NiCds back into 'productive
behavior' ...


----- Original Message -----
From: "Jinx" <joecolquitt@CLEAR.NET.NZ>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Saturday, June 01, 2002 7:59 PM
Subject: Re: [EE]: Laptop battery fading


> >     "Immediately the voltage starts to rise
> >      you disconnect the 15V."
> >
> > 'splain to me how this works again - minding
> > Ohm's Law?
>
> I agree that zapping is more applicable in general - it may
> take several goes but should work eventually, and this is
> my preferred method. My experience with the brute force
> voltage method is that you can do this with a cell that shows
> 0.00 or thereabouts after normal charging has been tried. It
> will take several seconds to break down the dendrites. Limiting
> the current available will minimise risk, but there has to be
> enough to punch through that barrier. As mentioned in the other
> post, this is an alternative to zapping, as very large caps
> probably aren't in many people's spare parts department
>
> Don't get the idea that I regard this as some Extreme Games
> event - if you don't watch what you're doing you could come
> unstuck
>
> > - this isn't like trying to charge a dead, stone
> > cold Lead-Acid cell ...
>
> Aren't dead Pb batteries dead forever ? I've always been
> led to believe that significant sulphate formation is irreversible,
> and leaving Pb batteries discharged for any length of time
> is unwise
>

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