Lead-Acid Battery Degradation, Repair/Replacement options?
Kyle
I've had an iMow rechargable lawnmower for about a year.
(http://www.toro.com/home/mowers/imow/index.html) Over the winter I
left it outside in the shed where it lives attached to its charger.
It was my understanding that this was the proper way to leave it for
an extended period of time. I live in the Wash DC area so we do go
below freezing for extended period of times (shed not heated, detached
from house). The charger is smart (indicates the difference between
when the batteries need charging and they are fully charged) so I
assumed it was operating in a trickle mode all winter.
When I cranked up the iMow this spring the length of each run had
deterioriated significantly - instead of 2-3 hours per charge I was
only getting half that much. I called toro support and they told me I
shouldnt have left it out in the cold all winter and said there was
nothing they could do for me short of selling me a new battery back
($120). Interestingly they said I was correct in leaving it
attached to the charger so I guess I was suppose to bring the whole
lawnmower in my house over the winter ?!? (no way to charge the
battery unless its sitting in the mower) My toro rant will be saved
for another post however...
Anyway, I took apart the battery pack and it consists of two Yuasa
NPC17-12 batteries connected together (in parallel I believe). The
NPC series appears to be designed for cyclic applications, its 17Ah x
12 volts - full details here:
http://www.yuasa-battery.co.uk/NP_Batteries.html
I pulled out the batteries separately and tested them with a
multimeter both fully charged and after running them through a mowing
cycle, they both gave the same readings which dashed my hopes that
only one of the batteries was underperforming and needed to be
replaced.
My questions are:
(1) Is there anything I can do to revive these batteries?
(2) And if not, is my best bet just buying two more Yuasa batteries
(cost about $100 for two with shipping) or is there some other battery
technology that I should consider - I was thinking that some sort of
multicell nimh battery pack would give much longer mowing time but
don't know how to approach designing such a custom battery pack or if
those batteries are appropriate for this type of application.
Thanks for any advice/answers...
N. Thornton
Lead acids are meant to be out in the cold all winter - cars'd be in
trouble if they weren't :). Sounds like you got dud batteries then.
Revival: yes. First thing is to check the electrolyte level and
correct if need be. Then ditto electrolyte strength - tho how you do
that with little widdly batts I dont know. Finally if you still havent
got good battery life they're probably sulphated. Charge them from a
high voltage (30v or more) thru a resistance to break down sulphation.
If all that fails, new battery.
Nimh will give you way less capacity per dollar. Car batts last 15 yrs
or so if taken care of, so lead acids are fine for the job.
If youve got space in there, you _could_ put a small used car battery
in it, or 2 6v motorbike batteries in series. You'll get several times
the capacity, but dont run them down. Stick to say 4 or 5 hrs mowing
at most, then recharge, then they'll last fine. If you run them right
down they wont. Or put new yuasas in. BTW there are other brands
similar to yuasa that are much cheaper.
Regards, NT
Sylvan Butler
> Anyway, I took apart the battery pack and it consists of two Yuasa
> NPC17-12 batteries connected together (in parallel I believe). The
Parallel is connecting both minus together and both plus together.
Then the motor connects also to the minus and to the plus.
Series would be connecting one minus to the other plus. Then the
motor connects to the remaining plus and minus.
> NPC series appears to be designed for cyclic applications, its 17Ah x
> 12 volts - full details here:
> http://www.yuasa-battery.co.uk/NP_Batteries.html
Much like these for $16/ea:
http://www.meci.com/default.asp?featured=true&partno=140-0094&mode=Search
(don't know anything about them other than some discussion in a
radio newsgroup a month or two ago)
> (1) Is there anything I can do to revive these batteries?
If normal usage does not do it, probably not.
I'm guessing either it wasn't really on charge on winter (came
unplugged or something) and they sulfated, or else they were
overcharged and cooked out a bit. In either case, sayonora.
> (2) And if not, is my best bet just buying two more Yuasa batteries
> (cost about $100 for two with shipping) or is there some other battery
I'd say that is probably the best bet. Might check with MECI.
> technology that I should consider - I was thinking that some sort of
> multicell nimh battery pack would give much longer mowing time but
> don't know how to approach designing such a custom battery pack or if
> those batteries are appropriate for this type of application.
Would work fine IF you could find big enough cells. It would cost a
small fortune. It would probably be lighter for the same energy or
more energy for the same weight. But very expensive... And you
would need a new charger that understood NiMH. That wouldn't be
cheap either, except when compared to the price of the cells.
sdb
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Fight terrorism, arm the population!
Kyle
Thanks - the toro rep sounded like she was making excuses but I didnt
even know what type of batteries was in it at the time so I was in no
position to argue about it
>Revival: yes. First thing is to check the electrolyte level and
>correct if need be. Then ditto electrolyte strength - tho how you do
>that with little widdly batts I dont know.
These are sealed batteries so I'm assuming that I can't do that -
please let me know if there is some trick that I dont know about
>Finally if you still havent
>got good battery life they're probably sulphated. Charge them from a
>high voltage (30v or more) thru a resistance to break down sulphation.
>If all that fails, new battery.
Check
>Nimh will give you way less capacity per dollar. Car batts last 15 yrs
>or so if taken care of, so lead acids are fine for the job.
Ok
>If youve got space in there, you _could_ put a small used car battery
>in it, or 2 6v motorbike batteries in series. You'll get several times
>the capacity, but dont run them down. Stick to say 4 or 5 hrs mowing
>at most, then recharge, then they'll last fine. If you run them right
>down they wont. Or put new yuasas in. BTW there are other brands
>similar to yuasa that are much cheaper.
Thanks again - I was wondering if the fact that Yuasa sells
rechargeables other than those designated "cyclic" meant that these
were special and that others wouldnt last in this application. It
sounds like thats not the case.
Kyle
<Znospam+...@hpb13799Z.Zboi.hpZ.com.invalid> wrote:
>On Wed, 19 Jun 2002 08:45:18 -0400, Kyle <Kyle-I...@invalid.com> wrote:
>> Anyway, I took apart the battery pack and it consists of two Yuasa
>> NPC17-12 batteries connected together (in parallel I believe). The
>
>Parallel is connecting both minus together and both plus together.
>Then the motor connects also to the minus and to the plus.
>
>Series would be connecting one minus to the other plus. Then the
>motor connects to the remaining plus and minus.
Oops my bad for not being more clear - I just meant I didnt have them
in front me when I was posting. I checked and they are in fact in
series not parallel.
>> NPC series appears to be designed for cyclic applications, its 17Ah x
>> 12 volts - full details here:
>> http://www.yuasa-battery.co.uk/NP_Batteries.html
>
>Much like these for $16/ea:
>http://www.meci.com/default.asp?featured=true&partno=140-0094&mode=Search
>
>(don't know anything about them other than some discussion in a
>radio newsgroup a month or two ago)
Cool thanks! Thats definitely a much better price than the yuasa
batteries
>> (1) Is there anything I can do to revive these batteries?
>
>If normal usage does not do it, probably not.
>
>I'm guessing either it wasn't really on charge on winter (came
>unplugged or something) and they sulfated, or else they were
>overcharged and cooked out a bit. In either case, sayonora.
Ok
>> (2) And if not, is my best bet just buying two more Yuasa batteries
>> (cost about $100 for two with shipping) or is there some other battery
>
>I'd say that is probably the best bet. Might check with MECI.
>
>> technology that I should consider - I was thinking that some sort of
>> multicell nimh battery pack would give much longer mowing time but
>> don't know how to approach designing such a custom battery pack or if
>> those batteries are appropriate for this type of application.
>
>Would work fine IF you could find big enough cells. It would cost a
>small fortune. It would probably be lighter for the same energy or
>more energy for the same weight. But very expensive... And you
>would need a new charger that understood NiMH. That wouldn't be
>cheap either, except when compared to the price of the cells.
Ahhhh, ok, I use a lot of AA nimh that seem pretty cheap these days
but I didnt know if you could get large sized cells (or multicell
packs) at reasonable prices.
Thanks for the info...
N. Thornton
> >> I've had an iMow rechargable lawnmower for about a year.
> >> (http://www.toro.com/home/mowers/imow/index.html) Over the winter I
> >> left it outside in the shed where it lives attached to its charger.
> >> It was my understanding that this was the proper way to leave it for
> >> an extended period of time. I live in the Wash DC area so we do go
> >> below freezing for extended period of times (shed not heated, detached
> >> from house). The charger is smart (indicates the difference between
> >> when the batteries need charging and they are fully charged) so I
> >> assumed it was operating in a trickle mode all winter.
> >>
> >> When I cranked up the iMow this spring the length of each run had
> >> deterioriated significantly - instead of 2-3 hours per charge I was
> >> only getting half that much. I called toro support and they told me I
> >Revival: yes. First thing is to check the electrolyte level and
> >correct if need be. Then ditto electrolyte strength - tho how you do
> >that with little widdly batts I dont know.
>
> These are sealed batteries so I'm assuming that I can't do that -
> please let me know if there is some trick that I dont know about
Thats a problem. Sulphation busting is probably your only revival
option then.
>
> >If youve got space in there, you _could_ put a small used car battery
> >in it, or 2 6v motorbike batteries in series. You'll get several times
> >the capacity, but dont run them down. Stick to say 4 or 5 hrs mowing
> >at most, then recharge, then they'll last fine. If you run them right
> >down they wont. Or put new yuasas in. BTW there are other brands
> >similar to yuasa that are much cheaper.
> Thanks again - I was wondering if the fact that Yuasa sells
> rechargeables other than those designated "cyclic" meant that these
> were special and that others wouldnt last in this application. It
> sounds like thats not the case.
Non cyclic, or 'thick plate' cells, such as car batteries, will not
last if you run them down. But non cyclic batts would be fine if you
got one of twice the capacity and only half discharged it each time.
But now I see you can get them for $16, that is evidently the easy way
to go. Good luck.
Regards, NT
Ian Stirling
>
> Kyle <Kyle-I...@invalid.com> wrote in message
>
>> >> I've had an iMow rechargable lawnmower for about a year.
>> >> (http://www.toro.com/home/mowers/imow/index.html) Over the winter I
>> >> left it outside in the shed where it lives attached to its charger.
>> >> It was my understanding that this was the proper way to leave it for
>> >> an extended period of time. I live in the Wash DC area so we do go
>> >> below freezing for extended period of times (shed not heated, detached
>> >> from house). The charger is smart (indicates the difference between
>> >> when the batteries need charging and they are fully charged) so I
>> >> assumed it was operating in a trickle mode all winter.
>> >>
>> >> When I cranked up the iMow this spring the length of each run had
>> >> deterioriated significantly - instead of 2-3 hours per charge I was
>> >> only getting half that much. I called toro support and they told me I
>
>> >Revival: yes. First thing is to check the electrolyte level and
>> >correct if need be. Then ditto electrolyte strength - tho how you do
>> >that with little widdly batts I dont know.
>>
>> These are sealed batteries so I'm assuming that I can't do that -
>> please let me know if there is some trick that I dont know about
>
> Thats a problem. Sulphation busting is probably your only revival
> option then.
Is there any valid sulphation busting technique, other than the
well-established, 100% method of sending the battery back to the
maker, so they can melt it down, and make new ones?
--
http://inquisitor.i.am/ | mailto:inqui...@i.am | Ian Stirling.
---------------------------+-------------------------+--------------------------
My inner child can beat up your inner child. - Alex Greenbank
John Mireley
> Is there any valid sulphation busting technique, other than the
> well-established, 100% method of sending the battery back to the
> maker, so they can melt it down, and make new ones?
>
Here is a "Lead Acid Battery Desulfation Pulse Generator"
http://www.flex.com/~kalepa/desulf.htm
There are a number of commercial products available.
The army did research on the topic and these desulfation
technologies work. Desulfators could be designed into
the battery. Guess why they aren't.
Steve Bolam
Stirling <ro...@mauve.demon.co.uk> writes
>
>>
>> Thats a problem. Sulphation busting is probably your only revival
>> option then.
>
>Is there any valid sulphation busting technique, other than the
>well-established, 100% method of sending the battery back to the
>maker, so they can melt it down, and make new ones?
>
Http://www.macbat.com
seem to think there is an alternative.
--
cut nocornedbeef to reply. http://www.Bolam.org
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`64 M Y*k L+++ U-- KQ++ C- c++ p++ R(HG3) I++ OP++
"An eye for an eye, will make the world blind!"
Sylvan Butler
> In article <1024576670.25177....@news.demon.co.uk>, Ian
> Stirling <ro...@mauve.demon.co.uk> writes
>>> Thats a problem. Sulphation busting is probably your only revival
>>> option then.
>>
>>Is there any valid sulphation busting technique, other than the
>>well-established, 100% method of sending the battery back to the
>>maker, so they can melt it down, and make new ones?
> seem to think there is an alternative.
Yup, they stand to make money if they can convince you. :)
And they strike me as at least over-hype, if not shady:
''The Macbat battery regenerator is a unique and revolutionary
innovation, ... ''
1) Their implementation may be unique, but the ideas, overall
techniques, etc. sure don't seem to be.
2) revolutionary? Right.
This is another one of those gray areas where people seem to get
sometimes good results, sometimes not. Every controlled (ie
scientific) study I've seen has shown inconclusive or outright
failure.
So if you can find one cheap (eg easily build the one mentioned in
another post, borrow or buy and return, or ???) or if you're
spending someone else's money (gov't job, perhaps?) then try it out.
Just don't bet your life on it working.
m...@here.com
> Is there any valid sulphation busting technique, other than the
> well-established, 100% method of sending the battery back to the
> maker, so they can melt it down, and make new ones?
Somewhere there's a battery faq that mentioned 2 methods:
for less severe sulphation, just hook up a charger that
puts out about 1A, and leave it on until the battery is
more or less restored, which might take several days.
For harder sulfation, replace the electrolyte with distilled
water (which dissolves sulphate better) and keep charging with
an amp or so current for a few days, then replace the electrolyte.
bradkazz
The type of batteries that you have suit this application due to the large
power density and ability to be cycled. They have a reduced life if they
are flattened to much during use and will last much longer if you only use a
small amount of powerduring each use, for example use only half the running
time and then recharge before the next use. In my experience they can not
usually be repaired. Another possible source is the medical field, these
batteries are common in life support equipment and they are changed every 2
years even if they are not faulty (for safety reasons). You could contact
your local hospitals Biomedical Engineers and ask if they have a tender
process for second hand batteries.
Good on you for saving the environment with an electric mower!
>
> Regards Brad
"Kyle" <Kyle-I...@invalid.com> wrote in message
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