There are two most common types of BMS on the market. The most obvious difference is one has "C-", and one hasn't. Please check the below pictures:

1. BMS with C- wire:

2. BMS without C- wire:

when charge port and discharge port are the same:

when charge port is not the same as discharge port:

Tips:

1. It's important to connect the B-wire first, then continue connecting the rest of balance wires.

2. You may need to solder a wire on the original B- or P- wire to extend their length.

3. If your charge port is not the same as the discharge port, please check the second picture, and in this case, you need to solder another wire of a certain length on the P- wire.