Using a 13S BMS for a 11S battery

Hello,

I'am building a 11S battery, I wanted to use a 13S BMS, but it seems it doesn't work :
I have 38.4 V measured directly on the battery (each cell is 3.5V)
And 34.6 V measured at BMS charging output (C-/C+), 32.7 V measured at BMS discharging output (P-/P+)

I have tried in connecting the last 2 wirings to the last cell, or letting them non connected, same values.
Here is a wiring diagram of the BMS.
Any idea of what could be wrong ?

Thanks !

Which last two did you connect? You should connect the B11, B12, and B13 lines together.
Also try measuring the cell voltages at the BMS to make sure all the wires are working.

Ok thanks for the advices Fechter.