Over the past few days, I’ve made a very simple 10s1p battery pack out of old 18650 batteries mainly for testing purposes and a bit fun. I am using an old BMS. 8 out of the 10, 18650’s are the same type of battery and came from the same laptop battery. The last 2 batteries came from a different battery are a different type. with 2 batteries being different from the other 8, I am finding when charging the pack, that those 2 batteries get overcharged up to 4.30v and the other 8 cells are at 4.10v. is this a broken BMS? or does your battery pack have to be made out of cells that are the same?
Thank you in advance, Max.