[EVDL List]

Hi,

I noticed an article by Home Power www.mrsharkey.com/nife2.pdf explaining
that CO2 gradually carbonates the KOH Potassium Hydroxide and electrolyte
needs to be replaced in the 5-15 year time frame. They show adding a
special mineral oil 1/8-3/16" on top "Chevron utility oil 22".

Is this necessary for flooded ni-cads like my STM5-180 Saft's? They show
replacing the electrolyte with the battery in a fully charged condition and
available from Pacific West Supply in oregon for $55 for 4 gallons (and you
return the used KOH to them).

What is the failure mode of Ni-Cads after say 2k -3k cycles? Do the plates
disintegrate like lead? Is it worth trying an electrolyte replacement when
they appear dead if at the speced end of life? I assume that would be it,
not to bother if they die at 2-3k. Home Power noted that 2K cycles is
typical (for me 40k miles) not the advertised 3k cycles or 60k miles.

Have a renewable energy day,
Mark

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[EVDL List]

It's been a long time, so I've forgotten the details, but about 8-10 years
ago I had some folks who had worked quite a bit with the Saft STM batteries
tell me that you should keep the caps on, don't even open them to check the
electrolyte level. They said that all their troubles started after they
opened the cells. I take that to mean that the watering system helps keep
the air and its CO2 out.

I think I've read that STMs have a bit of lithium in the electrolyte. I
don't know in what form or how much. So I don't think you can just dump in
new KOH and be good to go.

When they reach the end of their useful cycle life, you can ship them back
to Saft to be rebuilt. What that entails, I don't know, but I'd guess that
they replace the separators and electrolyte. As I understand it, the
electrodes don't change composition in the charge/discharge reactions, and
so shouldn't be degraded - but I'm not 100% positive about that.

I guess the operative phrase in the above is "I don't know." Lots of
speculation here, but maybe it will help a little.

David Roden
EVDL Administrator
http://www.evdl.org/


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Yes i heard about that electrolyte replacement, it's used if watering have
been made before servicing charge, resulting in electrolyte mess
(deconcentration)
To solve this you can purchase special electrolyte replacement by gallon can
at Saft for your model batteries.
replacing it use same way than water refiling.
If well used and water filled often, they show beautiful state material
plate even after 100 000km, changing electrolyte is a good idea but generaly
separator short circuit is the killing problem.


2007/8/27, Mark Hanson <[email protected]>:
>
> Hi,
>
> I noticed an article by Home Power www.mrsharkey.com/nife2.pdf explaining
> that CO2 gradually carbonates the KOH Potassium Hydroxide and electrolyte
> needs to be replaced in the 5-15 year time frame. They show adding a
> special mineral oil 1/8-3/16" on top "Chevron utility oil 22".
>
> Is this necessary for flooded ni-cads like my STM5-180 Saft's? They show
> replacing the electrolyte with the battery in a fully charged condition
> and
> available from Pacific West Supply in oregon for $55 for 4 gallons (and
> you
> return the used KOH to them).
>
> What is the failure mode of Ni-Cads after say 2k -3k cycles? Do the
> plates
> disintegrate like lead? Is it worth trying an electrolyte replacement
> when
> they appear dead if at the speced end of life? I assume that would be it,
> not to bother if they die at 2-3k. Home Power noted that 2K cycles is
> typical (for me 40k miles) not the advertised 3k cycles or 60k miles.
>
> Have a renewable energy day,
> Mark
>
> _________________________________________________________________
> Messenger Caf=E9 =97 open for fun 24/7. Hot games, cool activities served
> daily.
> Visit now. http://cafemessenger.com?ocid=3DTXT_TAGHM_AugHMtagline
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
_______________________________________________
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----- Original Message -----
From: "Mark Hanson" <[email protected]>
To: <[email protected]>
Sent: Monday, August 27, 2007 12:57 PM
Subject: [EVDL] NI-Cad Electrolyte Replacement


> Hi,
>
> I noticed an article by Home Power www.mrsharkey.com/nife2.pdf explaining
> that CO2 gradually carbonates the KOH Potassium Hydroxide and electrolyte
> needs to be replaced in the 5-15 year time frame. They show adding a
> special mineral oil 1/8-3/16" on top "Chevron utility oil 22".
>
> Is this necessary for flooded ni-cads like my STM5-180 Saft's? They show
> replacing the electrolyte with the battery in a fully charged condition
> and
> available from Pacific West Supply in oregon for $55 for 4 gallons (and
> you
> return the used KOH to them).
>
> What is the failure mode of Ni-Cads after say 2k -3k cycles? Do the
> plates
> disintegrate like lead? Is it worth trying an electrolyte replacement
> when
> they appear dead if at the speced end of life? I assume that would be it,
> not to bother if they die at 2-3k. Home Power noted that 2K cycles is
> typical (for me 40k miles) not the advertised 3k cycles or 60k miles.

> Hi Mark, an' All;

I have reverse engineered Ni Cads(Blown them up!)Scrapnel went all over
my garage, STILL find plastic shards in cleanups!Was amazed how pure and
CLEAN the plates, separaters, etc were. Just rinced the Ko away, and they
are objects 'de aet in my family room shelf.So, I think a "rebuild" job on
them is to wash 'em out and fill with new electrolyte, I was gunna
say"juice" but that, too.If you have ever destructed Led Acids, you KNOW
what a mooky MESS they are!?Active meterial in the "bilge" shedded off the
grids. This is WHY the magic battery rejuivenaters are a joke. They can't
put the active material back on the plate grids, the goop that makes the
damn battery work in the first place.

> Have a renewable energy day,

I'll try!

Bob

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