Question about Phase Amps and Line amps

[Elmo_nito123]

Hello, I have an 8.3kWh battery (83V nominal, 100Ah) LifePo4, QS 273 40H 3T. The problem is that due to space issues in the structure of my e-bike, I had to use a BMS with 100A continuous and 200A peak. I have a Sabvoton SVMC72200 that I used to use with 60V and it worked well, I know that using 83V nominal (Sabvoton only supports 94V) could damage it. I have been using a Votol EM-50s and I have noticed that with my voltage, the controller sometimes goes into protection, so I will opt for a Fardriver and sell my Sabvoton. The issue here is the following, I plan to buy the Fardriver ND96680 but is it possible to have the following configuration?

- 100A line current
- 680A phase current

I am not really interested in reaching 300A discharge because I know that controller can do it but not my BMS. So what I am mainly looking for is quick torque at each traffic light, according to AI (chatgpt) I would get rapid acceleration up to 40km/h and then progressively.

But according to Gemini, the controller will cut off the current because there is a maximum 4.5:1 ratio in the FarDriver. How true is that? According to Gemini, the FarDriver will correct the configuration and set 450A per phase instead of 680A because I need at least 200A of line amperage to be able to use 680A per phase.

I have never used FarDriver, I am looking for the experience of someone who has used it, I repeat that I can only discharge a maximum of 100 amps and my goal is only to generate a lot of torque/acceleration when each traffic light turns green even though I know that from around 40-50km/h I will start gaining speed progressively.

 

[dominik h]

Yes this is possible.
I use a ND721800 with 400A line an 1400A phase current in my scooter. Max line amps is reached around 35km/h
You can enter wathever you want. The value that is overshoot at first will automatically reduce the other value.

With that settings, you will have full tourque from start and then very soon the tourque will drop, because you reach your max line amps at low speeds.
You can try to use the time dependend boost values.
Which BMS do you use?
My 200A JK does 400A for more than 30seconds without any problems.
At 500A for 13 seconds it died.
I tested it to death with an electronic load, to find the true limits.

 

[Elmo_nito123]

Yes this is possible.
I use a ND721800 with 400A line an 1400A phase current in my scooter. Max line amps is reached around 35km/h
You can enter wathever you want. The value that is overshoot at first will automatically reduce the other value.

With that settings, you will have full tourque from start and then very soon the tourque will drop, because you reach your max line amps at low speeds.
You can try to use the time dependend boost values.
Which BMS do you use?
My 200A JK does 400A for more than 30seconds without any problems.
At 500A for 13 seconds it died.
I tested it to death with an electronic load, to find the true limits.

This is my BMS is a JK current 100A and max cur:200A


I use 2 Lifepo4 battery blocks which together add up to 83V (12s and 14s both 100Ah) nominally, and with both blocks charged it reaches up to 87V. In each battery block I have 1 BMS, which I am showing you, so is it possible to do a 200A discharge? How long would you recommend doing it, I have seen previous comments in posts related to 'phase amps and line amps' and I see that you have experience on the subject. The truth is that the use I will give it is only city use, not competition, and the accelerations will only be at key moments or for overtaking.

 

[dominik h]

It will at least take 200A for 30 seconds, which is more then enough to accelerate.

I set my Controller to limit current over 105km/h to save values for the bms.
You can adjust the current the controller gets at the ratios of speed, but remember the values are phase current multiplied with the ratio at a certain rpm.
600pA x 10% will give you 60A phase current. With that you can tune your controller to not kill the bms at higher speeds.

Or If you get the boost function running, you can set the highest phase current in boost mode and reduce the standard phase current.
The controller will leave boost mode after the entered boost time.

 

[n00b]

This thread reminds me I need a nice soldering gun.