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02-12-2009, 06:37 AM
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EVDL List Bot
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Posts: 70
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[EVDL] Ni-Cad wear out life/refurbishing
Hi,
[top]
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 mi=
les away, had to walk to the top of the mountain last night & get my tow ve=
hicle).
[top]
I've heard different old age scenarios of how the batteries wear out from d
ifferent people, Saft etc, since I'm not a chemist, I'm not sure which is a=
ccurate. I heard from Saft that they wear out, plates etc at 3K cycles (li=
ke 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.
[top]
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?
[top]
Have a renewable energy day,
Mark in Roanoke, VA
__________________________________________________ _______________
Windows Live
99: E-mail. Chat. Share. Get more ways to connect. =
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02-12-2009, 07:05 AM
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EVDL List Bot
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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.
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02-12-2009, 08:48 AM
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EVDL List Bot
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Re: [EVDL] Ni-Cad wear out life/refurbishing
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" <marke.xxx@xxx.xxx>
To: <xxx@xxx.xxx.edu>
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
__________________________________________________ _______________
Windows Live=99: E-mail. Chat. Share. Get more ways to connect.
http://windowslive.com/explore?ocid=3DTXT_TAGLM_WL_t2_allup_explore_02200 9
_______________________________________________
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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02-12-2009, 11:35 AM
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EVDL List Bot
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Join Date: Jul 2007
Posts: 70
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Re: [EVDL] Ni-Cad wear out life/refurbishing
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: xxx@xxx.xxx Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: xxx@xxx.xxx
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: xxx@xxx.xxx.edu [mailto:xxx@xxx.xxx.edu] 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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02-12-2009, 12:59 PM
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EVDL List Bot
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Join Date: Jul 2007
Posts: 70
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Re: [EVDL] Ni-Cad wear out life/refurbishing
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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02-12-2009, 03:25 PM
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EVDL List Bot
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Join Date: Jul 2007
Posts: 70
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Re: [EVDL] Ni-Cad wear out life/refurbishing
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
[quote] EVDL Administrator <xxx@xxx.xxx>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
> 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/
>
>
> _______________________________________________
> 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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02-12-2009, 04:05 PM
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EVDL List Bot
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Re: [EVDL] Ni-Cad wear out life/refurbishing
[quote]Mark Hanson wrote:
> 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 L=
ee) that the separators fatigue and can be sent back. I've also heard that=
(I think from Neon John) that the potassium hydroxide electrolite graduall=
y 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 dischar=
ge prior to changing?
> =
> Have a renewable energy day,
> Mark in Roanoke, VA
> __________________________________________________ _______________
> Windows Live=99: E-mail. Chat. Share. Get more ways to connect. =
> http://windowslive.com/explore?ocid=3DTXT_TAGLM_WL_t2_allup_explore_02200 9
> _______________________________________________
> 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
>
>
> =
Someone has 16 NiCd stn 5-180 batteries listed on the EV Trading Post.
Bill
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02-12-2009, 10:45 PM
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EVDL List Bot
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Re: [EVDL] Ni-Cad wear out life/refurbishing
[quote]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
> drops off drastically. This seems fairly consistent across the pack.
I'm far from an expert, so I hope someone will knock me aside if this is
rubbish -- however, this sounds like the phenomenon I've heard called
"voltage depression."
I would try re-initializing (commissioning) the pack. Discharge it to below
5 volts per module. Make sure the modules are below 35 deg C. Apply a
constant current charge of 7 amps for 21 hours. Voltage may go as high as 9
volts per module. Monitor module temperature and back down the current or
shut off for a while if the hottest one exceeds 50 deg C.
That's it, simple as that. See if that helps.
David Roden - Akron, Ohio, USA
EVDL Administrator
= = = = = = = = = = = = = = = = = = = = = = = = = = =
EVDL Information: http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = =
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02-12-2009, 10:56 PM
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EVDL List Bot
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Re: [EVDL] Ni-Cad wear out life/refurbishing
[quote]On 12 Feb 2009 at 14:55, Bill & Nancy wrote:
> EV Trading Post...
Speaking of which, am I the only one for which nothing works on this
website? When I click on a trading post item to view, I get a blank screen
with the title at the top reading "GIF Image, 32x32 pixels." I use a
Mozilla variant.
David Roden - Akron, Ohio, USA
EVDL Administrator
= = = = = = = = = = = = = = = = = = = = = = = = = = =
EVDL Information: http://www.evdl.org/help/
= = = = = = = = = = = = = = = = = = = = = = = = = = =
Note: mail sent to "evpost" or "etpost" addresses will not
reach me. To send a private message, please obtain my
email address from the webpage http://www.evdl.org/help/ .
= = = = = = = = = = = = = = = = = = = = = = = = = = =
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02-12-2009, 11:07 PM
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EVDL List Bot
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Re: [EVDL] Ni-Cad wear out life/refurbishing
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
[quote] EVDL Administrator wrote:
> On 12 Feb 2009 at 14:55, Bill & Nancy wrote:
>
>> EV Trading Post...
>
> Speaking of which, am I the only one for which nothing works on this
> website? When I click on a trading post item to view, I get a blank
> screen
> with the title at the top reading "GIF Image, 32x32 pixels." I use a
> Mozilla variant.
>
> David Roden - Akron, Ohio, USA
> EVDL Administrator
>
> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
> EVDL Information: http://www.evdl.org/help/
> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
> Note: mail sent to "evpost" or "etpost" addresses will not
> reach me. To send a private message, please obtain my
> email address from the webpage http://www.evdl.org/help/ .
> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>
>
> _______________________________________________
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>
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