Suzuki 125 build battery question

[Billetboy]

QS 138 v3 gear reduction build on Suzuki 125. Is P42a 20s 10p is enough power? Is a 400 amp bms safe for this pack configuration? max amps on the pack would be 450a. but i want the pack to last. Thank i’m advance

 

[KiefRichards]

I used the same batteries. With cooper series connections.

I tested my 9p pack at 300A and it reached 55c in 60 seconds.

I found the batteries’ limitations are thermal.
So, given good, low-resistance connections, you can get 45A from these cells, but not for long.

I plan on running my 9p pack at 250-300A bursts, but don’t expect to be able to run it continuously at those levels.

I used the Ant 180/450 bms

 

[Billetboy]

That’s what i was afraid of. Seems everyone uses EV cells. i want to track it for 10-15 minutes at a times, so 21700 cells don’t seemed to be the right choice.

 

[DogDipstick]

You need about 14p for a good, solid, 300A from a p42a pack. Given all IR is congruent. I have seen some very powerful p42A built batteries. 10p is still going to be really strong.

 

[Billetboy]

You need about 14p for a good, solid, 300A from a p42a pack. Given all IR is congruent. I have seen some very powerful p42A built batteries. 10p is still going to be really strong.

Thanks…KeifRichards posted his 9p pack got pretty hot in 60 seconds. you think the additional parallel cells would solve that heat issue? I am not sure what i can fit yet. Maybe 11
or 12p hopefully.

 

[KiefRichards]

You need about 14p for a good, solid, 300A from a p42a pack. Given all IR is congruent. I have seen some very powerful p42A built batteries. 10p is still going to be really strong.

Thanks…KeifRichards posted his 9p pack got pretty hot in 60 seconds. you think the additional parallel cells would solve that heat issue? I am not sure what i can fit yet. Maybe 11
or 12p hopefully.

I have a quick video of a p42a 4s1p pack @33A showing temp rise. Unfortunately, I didn’t record when I tested the 9p20s pack. The values I extrapolated from the 4s pack scaled well to the 9p20s pack.

https://youtu.be/pB0ehRhq_7M

Edit:
A 14p pack at 300A is around 21.5A per cell. I tested my 4s1p pack at 21.5A. It went from 21 to 60 degrees in 5 minutes 10 seconds. I think I’d want at least 20p for a 300A track bike. At that point Id go with ev cells.

 

[Billetboy]

You need about 14p for a good, solid, 300A from a p42a pack. Given all IR is congruent. I have seen some very powerful p42A built batteries. 10p is still going to be really strong.

Thanks…KeifRichards posted his 9p pack got pretty hot in 60 seconds. you think the additional parallel cells would solve that heat issue? I am not sure what i can fit yet. Maybe 11
or 12p hopefully.

I have a quick video of a p42a 4s1p pack @33A showing temp rise. Unfortunately, I didn’t record when I tested the 9p20s pack. The values I extrapolated from the 4s pack scaled well to the 9p20s pack.

https://youtu.be/pB0ehRhq_7M

Edit:
A 14p pack at 300A is around 21.5A per cell. I tested my 4s1p pack at 21.5A. It went from 21 to 60 degrees in 5 minutes 10 seconds. I think I’d want at least 20p for a 300A track bike. At that point Id go with ev cells.

Thanks for running that test. That is disappointing, but at least I know now before ordering a battery. I am not sure I want to tackle building an EV cell so I guess I was shelf the 125 build until I can figure out a battery solution.