I am trying to build a 4S 8P pack with cells collected from broken laptops.
After checking the cells (voltage, capacity, internal resistance), I selected the best ones to assemble my pack which will be 14.4V 19Ah.
Now, I purchased a (cheap) BMS 4S 30A with balancing feature.
I connected the B- to negative pole of the pack (black wires), and when connecting the B1 (blue wire) to the positive of the first parallel group, I get sparks and wire gets super hot quickly.
I am following the diagram below and I don’t know what is wrong.. Any idea is much appreciated!
Good day All