# Where are the Hi-Power Cells?



## somanywelps (Jan 25, 2012)

A123?

10char


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## LithiumaniacsEVRacing (Oct 9, 2010)

somanywelps said:


> A123?
> 
> 10char


A123 pouch cells will weigh much more than 5000grams to get anywhere close to 3000amps.


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## Arlo (Dec 27, 2009)

4 of these http://www.hobbyking.com/hobbyking/..._5600mah_1S2P_65_130C_Hardcase_Lipo_Pack.html
Would be just under 3000 amps. And weigh 608 grams!
5 would be well over 3000 amps and weigh 760 grams! 
I have personally pushed these batteries past their limits and I know others who have done it more scientifically and found that their ratings don't lie!

And If and when i build performance bikes/cars I comepare price of these to you and I compare the cycle life vs the price as well! Right now I am still buying hobby lipo because its so much cheeper and still has the performance I need!


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## LithiumaniacsEVRacing (Oct 9, 2010)

Arlo said:


> 4 of these http://www.hobbyking.com/hobbyking/..._5600mah_1S2P_65_130C_Hardcase_Lipo_Pack.html
> Would be just under 3000 amps. And weigh 608 grams!
> 5 would be well over 3000 amps and weigh 760 grams!
> I have personally pushed these batteries past their limits and I know others who have done it more scientifically and found that their ratings don't lie!
> ...


These are new cells from Turnigy sold in 1S2P hard cases, at 5.6ah X 130c = 728amps (awesome) and they weigh only 152g. Now lets break them down, one cell is 2.8ah and 130c = 364amps. To get 4000amps you would need 11 (1S) cells in Parallel = 4004amps @ 1672grams. Not bad weight, but now add in the connection method and tab size?


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## MN Driver (Sep 29, 2009)

Don't you mean one cell is 2.8Ah and 130C. The C rating of each cell doesn't change. The total amperage is cumulative though. You would need 11 in parallel for the 4000 amps and this is assuming their specs are reliable. If this is 130C but with high voltage sag you'll need either a higher total pack voltage to account for the sag, add even more in parallel, both of these options add more weight, or take a hit on performance. It's a compromise, of course you need to be able to flow 4000 amps without going into motor meltdown.


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## Arlo (Dec 27, 2009)

MN Driver said:


> Don't you mean one cell is 2.8Ah and 130C. The C rating of each cell doesn't change. The total amperage is cumulative though. You would need 11 in parallel for the 4000 amps and this is assuming their specs are reliable. If this is 130C but with high voltage sag you'll need either a higher total pack voltage to account for the sag, add even more in parallel, both of these options add more weight, or take a hit on performance. It's a compromise, of course you need to be able to flow 4000 amps without going into motor meltdown.


These cells have very low sag and do meet and exceed the specs!


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## Yabert (Feb 7, 2010)

LithiumaniacsEVRacing said:


> A123 pouch cells will weigh much more than 5000grams to get anywhere close to 3000amps.


Why?

5 cells at 30C (600A) = 3000A. 
496g each + some hardware > 3000g


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## somanywelps (Jan 25, 2012)

LithiumaniacsEVRacing said:


> A123 pouch cells will weigh much more than 5000grams to get anywhere close to 3000amps.


Check your math.


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## LithiumaniacsEVRacing (Oct 9, 2010)

Yabert said:


> Why?
> 
> 5 cells at 30C (600A) = 3000A.
> 496g each + some hardware > 3000g


Incorrect data, I was told by a tech at Mavizan the A123 AMP20 Pouch cells do not put out those discharge numbers.


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## LithiumaniacsEVRacing (Oct 9, 2010)

Yabert said:


> Why?
> 
> 5 cells at 30C (600A) = 3000A.
> 496g each + some hardware > 3000g


I was told the max discharge (amps) from an A123 AMP20 Pouch cell is 300 to 400amps, please prove me wrong. Do not use the Mavizan website, I was told the stats are not correct. This might help:

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA548025


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## rwaudio (May 22, 2008)

LithiumaniacsEVRacing said:


> Incorrect data, I was told by a tech at Mavizan the A123 AMP20 Pouch cells do not put out those discharge numbers.


There is only so much you can take someone's word on before you have to prove/disprove it yourself.

It's much like the connection method I PM'd you about, I don't expect you to take my word for it, the only way I would expect you to see the benefit would be from your own testing either on the bench or on the track.


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## rwaudio (May 22, 2008)

LithiumaniacsEVRacing said:


> I was told the max discharge (amps) from an A123 AMP20 Pouch cell is 300 to 400amps, please prove me wrong. Do not use the Mavizan website, I was told the stats are not correct. This might help:
> 
> http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA548025


I would challenge the thought that practical military use would be about as far from drag racing as you could get. For military use it must operate at that specification over an extreme temperature range for many more cycles at longer or at least repeated use.

I use some "mil spec" resistors in my headphone amplifiers, a mil spec 1/8 watt resistor is the same size as a 1/4 watt and a 1/4 watt resistor is the same size as a normal 1/2 watt resistor.... de-rating on purpose for failsafe use?

Compare these two virtually identical resistors, one consumer/industrial grade and the other official mil spec.
http://www.vishay.com/docs/31018/cmfind.pdf
http://www.vishay.com/docs/31027/cmfmil.pdf

If you were building a ambulance or fire truck that just had to work 100% without fail, I'd go with the mil spec rating, since you are pushing the limits of weight and power for very small periods of time I'd be comfortable pushing past the military rating on these cells.


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## Batterypoweredtoad (Feb 5, 2008)

Didn't Jack at EVTV test an A123 pouch cell at 600 amps? I think the guy on endlesssphere may have as well.


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## LithiumaniacsEVRacing (Oct 9, 2010)

Batterypoweredtoad said:


> Didn't Jack at EVTV test an A123 pouch cell at 600 amps? I think the guy on endlesssphere may have as well.


Okay, I will research. I like A123 pouch cells, its much easier to build a pack with less in parallel. I just need some confirmation they can produce 600amps and for how many cycles?


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## LithiumaniacsEVRacing (Oct 9, 2010)

Batterypoweredtoad said:


> Didn't Jack at EVTV test an A123 pouch cell at 600 amps? I think the guy on endlesssphere may have as well.


All I can find on EVTV is Jack testing the cells to a maximum of 475amps for 30 seconds. I do not see any 600amp tests ?


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## rwaudio (May 22, 2008)

LithiumaniacsEVRacing said:


> All I can find on EVTV is Jack testing the cells to a maximum of 475amps for 30 seconds. I do not see any 600amp tests ?


I don't think Jack did a 600A test, but 475 for 30 seconds should sound promising when all you need is 600A for 4-8 seconds at most in a run. Jack didn't reach the absolute limits of the cell, he reached the limits of his test equipment.


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## Batterypoweredtoad (Feb 5, 2008)

LithiumaniacsEVRacing said:


> All I can find on EVTV is Jack testing the cells to a maximum of 475amps for 30 seconds. I do not see any 600amp tests ?


I apologize for unverifiable information. I searched my bookmarks and couldn't find the thread with the guy doing load tests and taking infrared pictures on endlesssphere. I will keep looking. I haven't seen any life cycle tests at extremely high amp draws so I can't help there.


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## Batterypoweredtoad (Feb 5, 2008)

OK-found the testing on endlessphere in this thread: 

http://endless-sphere.com/forums/viewtopic.php?f=14&t=15093&hilit=A123+20Ah+test&start=105#p232895 

He is testing both the 15ah and the 20ah. With the 20ah he runs the cell at 80% PWM of a 600 amp load for a load of 480 Amps on the cell. He continues the test to 95% of the cells capacity before stopping due to the solder melting on the load bank. So that is apparently not a 600 amp continuous test either. It is though another higher than 450 amp test done almost all the way through the cells full capacity with no issues for the cell.


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## LithiumaniacsEVRacing (Oct 9, 2010)

Batterypoweredtoad said:


> OK-found the testing on endlessphere in this thread:
> 
> http://endless-sphere.com/forums/viewtopic.php?f=14&t=15093&hilit=A123+20Ah+test&start=105#p232895
> 
> He is testing both the 15ah and the 20ah. With the 20ah he runs the cell at 80% PWM of a 600 amp load for a load of 480 Amps on the cell. He continues the test to 95% of the cells capacity before stopping due to the solder melting on the load bank. So that is apparently not a 600 amp continuous test either. It is though another higher than 450 amp test done almost all the way through the cells full capacity with no issues for the cell.


Very cool, thank you!


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