Wanted to add a BMS just for charging and got one of the Chinese 12A BMS - wired it up with the SAME Balance Adapter - red and black went to B+ and B- on the BMS (parallel to the Main Leads + & - of the Battery) and as I pluged in the Balance Lead the + and the - leads went up in smoke as well as some parts on the BMS itself 
Only the 2 LiPos were connected in Series and the Balance leads - NO charger was plugged in.
Unplugged everything and the + and - of the Balance lead were totally fried.
Checked back wether there was a short cut between some of the wires - couldn find one.
As I unplugged everything during the smoke - and cause could be that I accidentally swapped the 2 Balance connectors of the the 2 LiPos - cant check back as its unplugged But I am nearly sure it was OK as I colour coded the 2 Lipos and there connectors including the Balance Adaptor connectors.
Now I ordered a new BMS but hesitate to solder it and connect it and blow it up in smoke again
May you could help me with my thoughts of connecting it right !?
Read a lot in here - but different topics offer different opinions.