Thank you Steve_S.
As mentionned, I was looking into buying a single BMS for the entirety of the project (Daly SmartBMS 500A common port) in the first « step » (8 batteries 280Ah for a 12,8V system -> 4 groups of [2 * 3,2V cells paralleled] in series for 560Ah). THEN, a year later, simply add 8...