If your controller only has a 200A battery (not phase!) current limit, then that means it would never draw more than 200A.
(If it doesn't have a battery current limit you can directly set, then you'd need to use whatever math the controller manufacturer provides to you directly in order to determine what that limit is. Just because you find someone else with the same *brand* of controller has a specific ratio and way their controller is setup, does not mean that yours will be the same, unless yours is exactly the same model *and* uses exactly the same firmware version, and possibly is setup exactly the same way theirs is in all other settings as well, because any of those things could change the way it behaves compared to theirs).
If it is drawing more than 200A, then either that is not it's battery current limit, or it is not obeying it's current limit until some set time has passed, allowing for unknown levels of peak current that you cannot control. For that, you'd have to experiment with the limits available to you in the controller setting, turning them down by whatever ratio is necessary to bring them below the worst-case system limitations.
So if you are seeing say, 400A battery currents but 200A is the most your system can tolerate, then 400A / 200A is 2:1, or 200%. To ensure you don't see more than 200A, you'd need to change the battery current limit in the controller by half, and retest.
If this still doesn't reduce it enough, you would need to either experiment further with even lower limits, or determine the math formula needed to use the new result plus the old result to give you the *real* ratio the system is using (which might even be a curve rather than a flat ratio, making this task very difficult as you can't know what curve it is if it's not in a manual or available from the controller manufacturer). I'm not good enough at math to do that sort of thing.
Note also that in order for you to say that the BMS's 375A peak current is 75% of the controller's peak current, it means you *must* already know the controller's peak current and have done the math (0.75 x controller peak amps = 375A). If you do *not* know the controller's peak current, then you cannot know that the BMS's peak current is any specific percentage of it, because you don't have the numbers available to calculate it. If you do know the number, either because you set it or because it's in the manual, what is the specific number you already know for the controller's peak amps?
If you don't know that number, then the 75% is not a valid ratio; the ratio is unknown and would need to be determined experimentally and by math from the results. If BMS peak current is a known limit number, call it BMSpkA, then the math is ControllerPkA / BMSpkA = actual ratio between them. Then you can use that to plug the actual limit numbers you want to use to get the ratio you need, if using a ratio is the only way to set a limit in the controller.
Also note that while peak amps are important to limit, the continuous amps are often more important in that they create continuous heating, which builds up in the components (cells, BMS, controller) and if this heat reaches damaging levels can cause catastrophic failures.
The same is true of peak amps, but if those are limited to a few seconds, every few minutes or less often, the heat they generate has time to dissipate, as long as it doesn't reach damaging levels during the few seconds, and doesn't exceed the limits of any part of the system (cells, cell interconnects, BMS, controller, and wiring / connectors between all those things).
jai134 said:
Thank You so much! I have to read it slowly a few times to understand.
Regarding settings, it is in percent (and that does it even more confusing for me) so the BMS's 375 Amps peak current is 75% of controllers peak Amps.
I think that my controller, it's a Kelly KLS 72501 8080i, has lowest continous current, 200A. Then "Battery limit" is around 40%?
As I understood the post I referred to in my first post, "Battery limit" is continous current and "current percent" is peak even though it doesn't say so in the manual.