[EVDL List]

Cor van de Water wrote:
> Want to ask the list for some help.
> I have a 12V battery of which one cell has been reversed
> (likely multiple times) because it was the first thing to go
> when the rest of the cells were still going strong.

There isn't anything that will restore its original capacity, except
melting it down and remanufacturing it. About the best you can do is
what you've already done -- recharge it in the correct direction, and
give it a very long hard equalization charge (which helps the bad cell a
little but damages the good cells a lot). At best, this might get it up
to 25%-50% of its original capacity.

One "cheap John" option is to short out the bad cell, so you can use the
rest as a 10v battery. I've done this by driving a bunch of stainless
steel screws into the bad cell. Also drain the acid if at all possible,
to eliminate corrosion.

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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[EVDL List]

>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On
> Behalf Of Lee Hart
> Sent: Saturday, October 06, 2007 6:20 PM
> To: Electric Vehicle Discussion List
> Subject: Re: [EVDL] Bringing a reversed battery back to life?
>

> Cor van de Water wrote:
>> Want to ask the list for some help.
>> I have a 12V battery of which one cell has been reversed
>> (likely multiple times) because it was the first thing to go
>> when the rest of the cells were still going strong.
>
> There isn't anything that will restore its original capacity, except
> melting it down and remanufacturing it. About the best you can do is
> what you've already done -- recharge it in the correct direction, and
> give it a very long hard equalization charge (which helps the bad cell a
>
> little but damages the good cells a lot). At best, this might get it up
> to 25%-50% of its original capacity.
>
> One "cheap John" option is to short out the bad cell, so you can use the
>
> rest as a 10v battery. I've done this by driving a bunch of stainless
> steel screws into the bad cell. Also drain the acid if at all possible,
> to eliminate corrosion.
>
> --
> Ring the bells that still can ring
> Forget the perfect offering
> There is a crack in everything
> That's how the light gets in -- Leonard Cohen
>


Lee,

>From this it sounds as if you may have glossed over the part where he mentioned that he had access to the individual cells.

Would you suggest charging the one cell with a long slow charge, or smoke it into submission.

I personally would open the vent and let it rip; In the hopes that a severe overcurrent would in some way perhaps breakup/burn-up the larger sulfate crystals. You can probably tell, I'm not a chemist. ;-)

I have a few batteries in the same condition..... some day, I'll try both of these methods

Do you know of a way to "open" a shorted cell? Assume I have isolated electrical access to the cell in question.

--
Stay Charged!
Hump
I-5, Blossvale NY

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