# [EVDL] Optimum A123 Racing Pack



## EVDL List (Jul 27, 2007)

I was thinking about what would be the ideal drag racing battery pack 
for my set up. I have a Warp 11 and a Z1K-HV. A 20kW lithium battery 
pack is on order which is optimized towards range, not power.

If I wanted decided to get a second "drag racing pack", what would the 
ideal parameters be for such a pack. As I understand it the Warp 
motor should be limited to about 160-170V. Got this from multiple 
sources, so is there any value in getting a battery pack that produces 
more than 1000 amps at 170V?

A123 cells seam like the gold standard for high power output. As I 
understand it the A123 26650 Cell can put out 70 Amps continuous and 
120 A (for 10 sec). I'm sure the voltage probably sags down to about 
2.5 V/cell at 70 Amps, so I figure a 15P68S pack is needed to put out 
1000 A at 170V. That's 1020 cells, and even if I can get them for $5/ 
each thats still $5,100 + BMS. I know others have spent way more, but 
I'm not sure I want to race that bad:^)

The new A123 32113 cells look very interesting. I assume they are 
about a 10Ah cell. If so, and they can put out 30C like their smaller 
counterpart, then you would only need 4P68S to get the same 
performance. That would only be 272 cells, but as far as I can tell 
they are unoptanium at this point.

Anybody have any thoughts along these lines.

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## EVDL List (Jul 27, 2007)

That sounds about right (2.5V/cell, 170V under max sag, 1000/70 in parallel)

Where do you plan on getting your cells? I guess for drag racing the
e-bay cells might be OK?

-Morgan LaMoore

On Wed, Nov 18, 2009 at 9:19 PM, Roger Heuckeroth


> <[email protected]> wrote:
> > I was thinking about what would be the ideal drag racing battery pack
> > for my set up. I have a Warp 11 and a Z1K-HV. A 20kW lithium battery
> > pack is on order which is optimized towards range, not power.
> ...


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## EVDL List (Jul 27, 2007)

I can see how higher voltage would help a Z2K with series /parallel 
shifting dual motor set up, but if you are running a standard single 
Warp 11 and are limited by the volts that the motor can take, would 
you really gain anything by having a 375V pack. I know that would put 
you in a class A3 instead of B.




> Bill Dube wrote:
> 
> > You need to look at the KillaCycle web page.
> > http://www.killacycle.com/photos/battery-assembly-110s-x-9p/
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > I can see how higher voltage would help a Z2K with series /parallel
> > shifting dual motor set up, but if you are running a standard single
> > Warp 11 and are limited by the volts that the motor can take, would
> ...


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## EVDL List (Jul 27, 2007)

Roger's numbers gave him a 218V nominal pack of 34.5Ah that could do
170V 1000A with fairly little battery sag.

Bill's numbers gave a 320V nominal pack of 18.5Ah that could do 170V
1000A with lots of battery sag.

Roger's described pack needs 1020 cells, while Bill's described pack
needs 800 cells. Both give the same final output power, but Roger's
puts less stress on the cells and provides more range (and cost and
weight).

-Morgan LaMoore

On Thu, Nov 19, 2009 at 8:18 AM, Ole-Egil Hvitmyren <[email protected]> w=
rote:


> > Roger Heuckeroth wrote:
> >> I can see how higher voltage would help a Z2K with series /parallel
> >> shifting dual motor set up, but if you are running a standard single
> >> Warp 11 and are limited by the volts that the motor can take, would
> ...


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## EVDL List (Jul 27, 2007)

> Ole-Egil Hvitmyren wrote:
> 
> > Roger Heuckeroth wrote:
> >> I can see how higher voltage would help a Z2K with series /parallel
> ...


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## EVDL List (Jul 27, 2007)

Voltage sag under load will result in a motor voltage of about 170 to 
180 volts.


At 07:11 AM 11/19/2009, you wrote:
>I can see how higher voltage would help a Z2K with series /parallel
>shifting dual motor set up, but if you are running a standard single
>Warp 11 and are limited by the volts that the motor can take, would
>you really gain anything by having a 375V pack. I know that would put
>you in a class A3 instead of B.
>
>
>


> Bill Dube wrote:
> >
> > > You need to look at the KillaCycle web page.
> > > http://www.killacycle.com/photos/battery-assembly-110s-x-9p/
> ...


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## EVDL List (Jul 27, 2007)

The question was "Optimum" racing pack.

The pack I suggested is the one that will produce the most HP with 
the least weight (without adding heaters or playing with bleeding off 
surface charge) into a Zilla with a motor that will withstand ~170 
volts. It is also the most HP per dollar under those constraints if 
you are using A123Systems cells.

One can move away from that optimum if additional constraints or 
conditions must be met. You can build a much more expensive and 
massive pack at a lower voltage. The car will go slower, but it might 
possibly be faster than others in a specific voltage class. That was 
not the question asked, however.

The pack I suggested would not be the very top voltage class. At the 
starting line, the pack voltage would be about 100 x 3.375 = 338 
volts. This would be in the A2 voltage class. You could drop down to 
97 cells in series to put yourself in the "A" voltage class. The car 
would go slower, of course.

What you must keep in mind is that there are open records in A, A1, 
and A2 voltage classes for Street Conversion (SC). Pro Street 
conversion (PS) has an open record in the A voltage class. Extreme 
Street (XS) has open records in A2 and A3.

You can see that it all depends on the specifics of the vehicle 
whether a lower voltage is an advantage in setting a record.

Bill Dube'

>Bill said that each cell will put out 130-135 A at half cell voltage
>(3.75/2 = 1.875V) That would be 8P cells to get 1000A. However, if
>you go for a stiffer pack like 15P68S, then you stay in a lower
>voltage class, and have more chance of holding a record.
>
>See: http://www.nedra.com/class_rules.html
>
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## EVDL List (Jul 27, 2007)

Bill,

Are any of the other larger cells that A123 has on their website 
available. Are you still using a 26650 pack?

Roger



> Bill Dube wrote:
> 
> > The question was "Optimum" racing pack.
> >
> ...


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