# [EVDL] Ni-Cad wear out life/refurbishing



## EVDL List (Jul 27, 2007)

Hi Mark,
What a coincidence, I've been thinking about asking the same
question all week!

> I have 16ea Saft STM5-180's in my E-Porsche that I've put 35k miles on in 2.5 years and the range is
> dropping from 35 miles to 30 miles (work is 30 miles away, had to walk to the top of the mountain last night & > get my tow vehicle).

I am currently using 20 STM5-100MREs. These are "reclaimed" ones so I
wasn't expecting much - they aren't declining noticeably but have a
very poor range of only 20 miles, which is a bit marginal in cold and
snowy weather.
The voltage holds up at 120V (with 1C load) until around 30-40% of
the capacity is used, which is normal, but then the voltage suddenly
drops off drastically. This seems fairly consistent across the pack.

>
> I've heard different old age scenarios of how the batteries wear out from different people, Saft etc, since I'm not
> a chemist, I'm not sure which is accurate. I heard from Saft that they wear out, plates etc at 3K cycles (like
> any other battery just take longer). I've also heard ( I think from Lee) that the separators fatigue and can be
> sent back. I've also heard that (I think from Neon John) that the potassium hydroxide electrolite gradually
> absorbs CO2 and if replaced will get another 35k out of the batteries.
>
> Sooo, which is true?

I'd really like to know this too. I somewhat doubt you'd be able to
get the separators replaced now though.

Another question: can you "top up" the alkalinity by adding potassium
hydroxide? As well as absorbing CO2, it seems possible that it gets
diluted a bit over time (as water is added).

Where can one obtain a suitable instrument for checking the specific
gravity? I think it's off the scale for the typical lead-acid ones,
and those don't seem very accurate anyway.

My batteries are sealed so I also have the problem of drilling holes
and sealing them afterwards.

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## EVDL List (Jul 27, 2007)

Hello Mark,

There is some place on the web I have seen the last century that has a list =

of military specs which shows how exactly to maintain the Ni-Cad batteries. =

Try different web sites on Ni-Cads Maintenance.

When I was working the battery shop, we had Ni-Cads with fill caps so we ca=
n =

perform the maintenance on the battery and potassium hydroxide (KOH).

The seal type batteries are produce to keep the person screwing up the =

battery chemistry if they do not have the training and/or battery lab.

The battery pack was pull from the aircraft every 30 days and each cell was =

pull from a rubber coated lined aluminum battery case. We than install =

shorting bars across the terminals and let set until the voltage went to =

about 0.01 Volts or as close to 0 volts as you can get and then stop this =

action so it does not get to 0 volts.

The KOH was remove from the battery and was never use again. The batteries =

were place upside down and place in a bath of distill water in a sonic =

cleaning tank. After the cleaning, new 1.200 SG KOH is install and each =

cell is charge separately with a charger that can charge 36 cells at the =

same time.

If the cell voltage did not come up to the specification voltage, then we =

sent it back to the depot to be discarded.

We than install the cells with the same manuf. dates back into the cases. =

We fully cover the cells with GE Silicone Di-electric grease so it was =

easier to press the cells in the boxes and to protect them.

New batteries should be at least be cycle about four or more times before =

putting in service, so it can reach its full capacity.

In a Ni-Cad battery, the KOH electrolyte does not change or very little =

change as it's discharge like a lead-acid battery. The KOH is only a =

carrier of electricity like a conductor, not a chemical exchange like the =

5H2O + 3H2SO4 that is a lead battery.

You can get this chemical or any other chemicals and testing equipment from =

Fisher Scientific/Instrumentation Laboratories which there are over 24 =

locations in the USA.

Roland




----- Original Message ----- =

From: "Mark Hanson" <[email protected]>
To: <[email protected]>
Sent: Thursday, February 12, 2009 5:33 AM
Subject: [EVDL] Ni-Cad wear out life/refurbishing



Hi,

I have 16ea Saft STM5-180's in my E-Porsche that I've put 35k miles on in =

2.5 years and the range is dropping from 35 miles to 30 miles (work is 30 =

miles away, had to walk to the top of the mountain last night & get my tow =

vehicle).

I've heard different old age scenarios of how the batteries wear out from =

different people, Saft etc, since I'm not a chemist, I'm not sure which is =

accurate. I heard from Saft that they wear out, plates etc at 3K cycles =

(like any other battery just take longer). I've also heard ( I think from =

Lee) that the separators fatigue and can be sent back. I've also heard tha=
t =

(I think from Neon John) that the potassium hydroxide electrolite gradually =

absorbs CO2 and if replaced will get another 35k out of the batteries.

Sooo, which is true? Does anyone know where to by NiCd electrolyte?

Do you fully charge the battery when replacing the electrolyte or discharge =

prior to changing?

Have a renewable energy day,
Mark in Roanoke, VA
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## EVDL List (Jul 27, 2007)

The fun thing with NiCd is that many of its
characteristics are the opposite of those
with other batteries.
Not only is the electrolyte a Base iso an Acid,
but also do they like to be stored discharged
and for equalization it is best to *completely*
discharge them. To *zero* volts.
Then you can do a full recharge with a controlled
overcharge (make sure you do not collect the H2 gas
or yo umay have the same explosive experience as
one member of the US Electricar group who converted
his truck to flooded NiCd and had the battery box
lid blown off after this process.

Note: watering the cells must only be done at the
end of the recharge, even if the cells seem dry
when you start the charge. The level comes up
quite dramatically and filling them too early 
will lead to a KOH mess.
(Note that it dissolves many metals, some have
found their alu battery box becoming flakey...)

After the equalization the capacity seems to be
increased according to what I hear.
They are spec'ed to have 20 years of service life
so you may have just broken them in...

I cannot relate to experience with carbonation and
replacement of the electrolyte, but that seems
logical if they have degraded from just sitting
and you can't bring them back by an equalization
*dis*charge.

Success,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Evan Tuer
Sent: Thursday, February 12, 2009 7:24 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Ni-Cad wear out life/refurbishing

Hi Mark,
What a coincidence, I've been thinking about asking the same
question all week!

> I have 16ea Saft STM5-180's in my E-Porsche that I've put 35k miles on
in 2.5 years and the range is
> dropping from 35 miles to 30 miles (work is 30 miles away, had to walk
to the top of the mountain last night & > get my tow vehicle).

I am currently using 20 STM5-100MREs. These are "reclaimed" ones so I
wasn't expecting much - they aren't declining noticeably but have a
very poor range of only 20 miles, which is a bit marginal in cold and
snowy weather.
The voltage holds up at 120V (with 1C load) until around 30-40% of
the capacity is used, which is normal, but then the voltage suddenly
drops off drastically. This seems fairly consistent across the pack.

>
> I've heard different old age scenarios of how the batteries wear out
from different people, Saft etc, since I'm not
> a chemist, I'm not sure which is accurate. I heard from Saft that
they wear out, plates etc at 3K cycles (like
> any other battery just take longer). I've also heard ( I think from
Lee) that the separators fatigue and can be
> sent back. I've also heard that (I think from Neon John) that the
potassium hydroxide electrolite gradually
> absorbs CO2 and if replaced will get another 35k out of the batteries.
>
> Sooo, which is true?

I'd really like to know this too. I somewhat doubt you'd be able to
get the separators replaced now though.

Another question: can you "top up" the alkalinity by adding potassium
hydroxide? As well as absorbing CO2, it seems possible that it gets
diluted a bit over time (as water is added).

Where can one obtain a suitable instrument for checking the specific
gravity? I think it's off the scale for the typical lead-acid ones,
and those don't seem very accurate anyway.

My batteries are sealed so I also have the problem of drilling holes
and sealing them afterwards.

_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev


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Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
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----------



## EVDL List (Jul 27, 2007)

About 10 years ago, I talked to someone from a solar racing team who had 
used Safts. He told me that Saft electrolyte is not just KOH and water; it 
contains trace additives, including lithium. 

His advice was to water the batteries, equalize and re-initialize when 
necessary, and otherwise don't mess with them. He told me that if you take 
the cell caps off, you'd better know what you're doing, because if you don't 
you'll probably lose more than you'll gain. His team had learned that 
lesson the hard way. 

That said, you might contact Saft and see if they sell premixed electrolyte. 
Saft also offer a rebuilding service, or at least they used to. I suspect 
that it's not cheap.

Another thought - Bob Schneeveiss used Saft NiCd batteries in at least one 
of his EVs, possibly a racing EV. He might be able to help, if you know how 
to get in touch with him. 

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


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----------



## EVDL List (Jul 27, 2007)

It's been quite a few years since I've replaced electrolyte on NiCad
batteries, but I recall it being mostly KOH, with a trace amount of LiOH.
We mixed it all up by hand from distilled water and dry flake. See if
www.beutilityfree.com has any info... they used to, but that was about 15
years ago last I did it.

Z



> EVDL Administrator <[email protected]>wrote:
> 
> > About 10 years ago, I talked to someone from a solar racing team who had
> > used Safts. He told me that Saft electrolyte is not just KOH and water; it
> ...


----------



## EVDL List (Jul 27, 2007)

> Mark Hanson wrote:
> > Hi,
> > =
> 
> ...


----------



## EVDL List (Jul 27, 2007)

> On 12 Feb 2009 at 13:53, Evan Tuer wrote:
> 
> > The voltage holds up at 120V (with 1C load) until around 30-40% of
> > the capacity is used, which is normal, but then the voltage suddenly
> ...


----------



## EVDL List (Jul 27, 2007)

> On 12 Feb 2009 at 14:55, Bill & Nancy wrote:
> 
> > EV Trading Post...
> 
> ...


----------



## EVDL List (Jul 27, 2007)

David,

Trading post works just fine with Safari on a Mac : )
Works fine with Firefox on a Mac too : )

Must be a PC glitch : )

Pete







> EVDL Administrator wrote:
> 
> > On 12 Feb 2009 at 14:55, Bill & Nancy wrote:
> >
> ...


----------



## EVDL List (Jul 27, 2007)

> EVDL Administrator <[email protected]> wrote:
> > On 12 Feb 2009 at 13:53, Evan Tuer wrote:
> >
> >> The voltage holds up at 120V (with 1C load) until around 30-40% of
> ...


----------



## EVDL List (Jul 27, 2007)

You should be able to measure S.G. with the same tool
as for lead-acids, just make sure that you never use
one tool on both, you need to have a dedicated S.G.
tester for KOH only.

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Evan Tuer
Sent: Friday, February 13, 2009 2:52 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Ni-Cad wear out life/refurbishing

On Fri, Feb 13, 2009 at 5:38 AM, EVDL Administrator <[email protected]>


> wrote:
> > On 12 Feb 2009 at 13:53, Evan Tuer
> 
> 
> ...


----------



## EVDL List (Jul 27, 2007)

> Cor van de Water <[email protected]> wrote:
> > You should be able to measure S.G. with the same tool
> > as for lead-acids,
> 
> ...


----------



## EVDL List (Jul 27, 2007)

> On Friday 13 February 2009 05:26 am, Evan Tuer wrote:
> > On Fri, Feb 13, 2009 at 10:06 AM, Cor van de Water <[email protected]>
> wrote:
> > > You should be able to measure S.G. with the same tool
> ...


----------



## EVDL List (Jul 27, 2007)

>


> > On 12 Feb 2009 at 14:55, Bill & Nancy wrote:
> >
> >
> >> > EV Trading Post...
> ...


----------



## EVDL List (Jul 27, 2007)

Hi,
=

Roland mentioned discharging all the way then dump & replace with new KOH. =
I would think that would overflow like it does if you don't wait until the=
end of charge to fill. I think if replacing the KOH it should be done whe=
n the battery is fully charged? I may have diluted my KOH over the last 35=
k miles even with the computer controlled spit detector (shuts off the char=
ger when spitting occurs)..
=

Best Regards,
Mark



Date: Thu, 12 Feb 2009 15:23:32 -0700Subject: Re: [EVDL] Ni-Cad wear out li=
fe/refurbishingFrom: [email protected]: [email protected]: marke.hanso=
[email protected]'s been quite a few years since I've replaced electrolyte on=
NiCad batteries, but I recall it being mostly KOH, with a trace amount of =
LiOH. We mixed it all up by hand from distilled water and dry flake. See =
if www.beutilityfree.com has any info... they used to, but that was about 1=
5 years ago last I did it.Z
On Thu, Feb 12, 2009 at 12:47 PM, EVDL Administrator <[email protected]> wrot=
e:
About 10 years ago, I talked to someone from a solar racing team who haduse=
d Safts. He told me that Saft electrolyte is not just KOH and water; itcon=
tains trace additives, including lithium.His advice was to water the batter=
ies, equalize and re-initialize whennecessary, and otherwise don't mess wit=
h them. He told me that if you takethe cell caps off, you'd better know wh=
at you're doing, because if you don'tyou'll probably lose more than you'll =
gain. His team had learned thatlesson the hard way.That said, you might co=
ntact Saft and see if they sell premixed electrolyte.Saft also offer a rebu=
ilding service, or at least they used to. I suspectthat it's not cheap.Ano=
ther thought - Bob Schneeveiss used Saft NiCd batteries in at least oneof h=
is EVs, possibly a racing EV. He might be able to help, if you know howto =
get in touch with him.David RodenEVDL Administratorhttp://www.evdl.org/


_______________________________________________General EVDL support: http:/=
/evdl.org/help/Usage guidelines: http://evdl.org/help/index.html#convArchiv=
es: http://evdl.org/archive/Subscription options: http://lists.sjsu.edu/mai=
lman/listinfo/ev
_________________________________________________________________
Windows Live=99: E-mail. Chat. Share. Get more ways to connect. =

http://windowslive.com/online/hotmail?ocid=3DTXT_TAGLM_WL_HM_AE_Faster_0220=
09
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## EVDL List (Jul 27, 2007)

When you dump the old KOH out and replace with new then
you must take care to fill back not more than came out,
because indeed the level rises significantly during charging!

Adding distilledd water is required and does not dilute,
because it serves to replace the water that was lost
during the charging (split into H and O gas) so the
KoH gets more concentrated with every charge and you
bring it back to normal by watering to the original
max level after you fully charged the pack.


Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 VoIP: +31 20 3987567 FWD# 25925
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Mark Hanson
Sent: Friday, February 13, 2009 11:20 PM
To: [email protected]
Subject: Re: [EVDL] Ni-Cad wear out life/refurbishing


Hi,

Roland mentioned discharging all the way then dump & replace with new
KOH. I would think that would overflow like it does if you don't wait
until the end of charge to fill. I think if replacing the KOH it should
be done when the battery is fully charged? I may have diluted my KOH
over the last 35k miles even with the computer controlled spit detector
(shuts off the charger when spitting occurs)..

Best Regards,
Mark



Date: Thu, 12 Feb 2009 15:23:32 -0700Subject: Re: [EVDL] Ni-Cad wear out
life/refurbishingFrom: [email protected]: [email protected]:
[email protected]'s been quite a few years since I've replaced
electrolyte on NiCad batteries, but I recall it being mostly KOH, with a
trace amount of LiOH. We mixed it all up by hand from distilled water
and dry flake. See if www.beutilityfree.com has any info... they used
to, but that was about 15 years ago last I did it.Z
On Thu, Feb 12, 2009 at 12:47 PM, EVDL Administrator <[email protected]>


> wrote:
> About 10 years ago, I talked to someone from a solar racing team who
> hadused Safts. He told me that Saft electrolyte is not just KOH and
> water; itcontains trace additives, including lithium.His advice was to
> ...


----------



## EVDL List (Jul 27, 2007)

Roland, If the electrolyte doesn't change, why were you replacing it??



> Roland Wiench <[email protected]> wrote:
> > Hello Mark,
> In a Ni-Cad battery, the KOH electrolyte does not change or very little
> change as it's discharge like a lead-acid battery. The KOH is only a
> ...


----------



## EVDL List (Jul 27, 2007)

It doesn't change in the normal chemical reaction of the battery, but as I
understand it, it asborbs carbon dioxide from the air (and carbon from
graphite plate separators for some poor designs) and turns into potassium
carbonate, instead of potassium hydroxide solution.

Z



> storm connors <[email protected]>wrote:
> 
> > Roland, If the electrolyte doesn't change, why were you replacing it??
> >
> ...


----------

