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Discussion Starter #1
Hi, Hopefully some of you have been down this road and can help. I
have a motorcycle converted with one Etek (brushed, Alltrax 48v
controller) around 6:1 drive ratio. My problem is that though I have
limited the Alltrax output to 150 amps, I still get many cell deaths
when using multiple DeWalt 36v packs. I usually run 4-7 parallel and
never let them go below 28 volts. The bike runs great and I can
consistently get about 1 mile to a pack (bike and rider are heavy and
many real hills where I am testing). Motor does not get hot at all by
end of drain. I have run the bike at 48v but lately have been using it
at 36v, which with the DeWalt is really 33v nominal. The bike is peppy
and fine. I tap each of the DeWalt packs before the BMS and come out on
a pair of 14ga wires which I then parallel for the multi-pack. The
batts get warm but no where near hot after riding. I charge using the
DeWalt charger and usually give awhile for the BMS to balance the pack.
So far I have killed about ten cells. They are from random places in
packs and usually only one in a 10s pack will go bad. Am I causing a
problem by not using perhaps 12ga wire? The 14ga never gets warm. I
cannot believe that too many amps output or too low cutoff voltage are
the problem. The amps is at least divided by four batts or more. Any
thoughts or help appreciated...
Jeff K. Burbank, CA "Deep Cycle" and "Bike to the Future"

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Discussion Starter #2
My guess would be that the batteries aren't sharing the load current
equally. I don't recall lithium batteries playing nice in parallel.
--
Martin K

Jeffrey P. Kloth wrote:
> Hi, Hopefully some of you have been down this road and can help. I
> have a motorcycle converted with one Etek (brushed, Alltrax 48v
> controller) around 6:1 drive ratio. My problem is that though I have
> limited the Alltrax output to 150 amps, I still get many cell deaths
> when using multiple DeWalt 36v packs. I usually run 4-7 parallel and
> never let them go below 28 volts. The bike runs great and I can
> consistently get about 1 mile to a pack (bike and rider are heavy and
> many real hills where I am testing). Motor does not get hot at all by
> end of drain. I have run the bike at 48v but lately have been using it
> at 36v, which with the DeWalt is really 33v nominal. The bike is peppy
> and fine. I tap each of the DeWalt packs before the BMS and come out on
> a pair of 14ga wires which I then parallel for the multi-pack. The
> batts get warm but no where near hot after riding. I charge using the
> DeWalt charger and usually give awhile for the BMS to balance the pack.
> So far I have killed about ten cells. They are from random places in
> packs and usually only one in a 10s pack will go bad. Am I causing a
> problem by not using perhaps 12ga wire? The 14ga never gets warm. I
> cannot believe that too many amps output or too low cutoff voltage are
> the problem. The amps is at least divided by four batts or more. Any
> thoughts or help appreciated...
> Jeff K. Burbank, CA "Deep Cycle" and "Bike to the Future"
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>

_______________________________________________
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Discussion Starter #3
they share very well in parrallel but have to be matched and not defective
to make this well...
imho you have some defective cells, it happen time to time on a production
line.
when you use 10 cells pack, 1% defective cell is less a problem than when
you use a pack made out of 100 for exemple

philippe


e2007/10/2, Martin Klingensmith <[email protected]>:
>
> My guess would be that the batteries aren't sharing the load current
> equally. I don't recall lithium batteries playing nice in parallel.
> --
> Martin K
>
> Jeffrey P. Kloth wrote:
> > Hi, Hopefully some of you have been down this road and can help. I
> > have a motorcycle converted with one Etek (brushed, Alltrax 48v
> > controller) around 6:1 drive ratio. My problem is that though I have
> > limited the Alltrax output to 150 amps, I still get many cell deaths
> > when using multiple DeWalt 36v packs. I usually run 4-7 parallel and
> > never let them go below 28 volts. The bike runs great and I can
> > consistently get about 1 mile to a pack (bike and rider are heavy and
> > many real hills where I am testing). Motor does not get hot at all by
> > end of drain. I have run the bike at 48v but lately have been using it
> > at 36v, which with the DeWalt is really 33v nominal. The bike is peppy
> > and fine. I tap each of the DeWalt packs before the BMS and come out on
> > a pair of 14ga wires which I then parallel for the multi-pack. The
> > batts get warm but no where near hot after riding. I charge using the
> > DeWalt charger and usually give awhile for the BMS to balance the pack.
> > So far I have killed about ten cells. They are from random places in
> > packs and usually only one in a 10s pack will go bad. Am I causing a
> > problem by not using perhaps 12ga wire? The 14ga never gets warm. I
> > cannot believe that too many amps output or too low cutoff voltage are
> > the problem. The amps is at least divided by four batts or more. Any
> > thoughts or help appreciated...
> > Jeff K. Burbank, CA "Deep Cycle" and "Bike to the Future"
> >
> > _______________________________________________
> > For subscription options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
> >
> >
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
_______________________________________________
For subscription options, see
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