Hello,
I am making a 12s7p system with 50Ah 4V (3.7V) lithium battery cells.
I believe I need a BMS for each string (7 BMS's) but I am confused to what amp BMS I need for each string of cells.
I have read where some people say that each BMS should be able to handle the full current load of the entire system ( assuming 350Ah based on a 5000W inverter 48V and 7 x 50Ah strings)) which means I would need 7 BMS's each rated a minimum of 350Amp in case one or more of the 7 BSM's fails, but others say just to use the amp for the String (5000W / 48V = 104Amp.) Could you please confirm which setup is correct, and also, how are all 7 BMS’s connected? Do I connect them in parallel?
Also, the busbars to connect each cell. Again, I am confused with this and not sure if they only need to handle the current for the string of cells (50aH battery, 5000W inverter at 48V). I am getting very confused to which ratings I need to work off. i.e. the full system current or the single string current or the battery current.
Finally, if I have 7 separate BMS's with Bluetooth connection to my phone app, would this mean that I need to swap in and out of each BMS on the phone app to check each string individually or is there a BMS that will link all the BMS's together so that I can see all 88 cells in the one app page?
Maybe there is a BMS available where I only need one BMS with 88 or more cell connections? I have looked but not sure if I can get away with one BMS for the whole system or whether I do need a BMS for each string.
Any help with this would be greatly appreciated.
Thank you very much, regards Dean
I am making a 12s7p system with 50Ah 4V (3.7V) lithium battery cells.
I believe I need a BMS for each string (7 BMS's) but I am confused to what amp BMS I need for each string of cells.
I have read where some people say that each BMS should be able to handle the full current load of the entire system ( assuming 350Ah based on a 5000W inverter 48V and 7 x 50Ah strings)) which means I would need 7 BMS's each rated a minimum of 350Amp in case one or more of the 7 BSM's fails, but others say just to use the amp for the String (5000W / 48V = 104Amp.) Could you please confirm which setup is correct, and also, how are all 7 BMS’s connected? Do I connect them in parallel?
Also, the busbars to connect each cell. Again, I am confused with this and not sure if they only need to handle the current for the string of cells (50aH battery, 5000W inverter at 48V). I am getting very confused to which ratings I need to work off. i.e. the full system current or the single string current or the battery current.
Finally, if I have 7 separate BMS's with Bluetooth connection to my phone app, would this mean that I need to swap in and out of each BMS on the phone app to check each string individually or is there a BMS that will link all the BMS's together so that I can see all 88 cells in the one app page?
Maybe there is a BMS available where I only need one BMS with 88 or more cell connections? I have looked but not sure if I can get away with one BMS for the whole system or whether I do need a BMS for each string.
Any help with this would be greatly appreciated.
Thank you very much, regards Dean