ESC telemetry with multiple battery levels

Hi All,

I am building a VTOL (4+1 motors) and I use esc telemetry to measure the battery voltage and current (don’t have dedicated battery monitor sensor). ESC telemetry is working, I am able to see both the 4 copter motors as well as the motor of forward flight voltage, rpm, current in the log file.

I have an ‘obvious’ issue though and I don’t know how to solve it.
The 4 VTOL motors are connected to 12S battery, while the forward motor is powered by a 6S battery.

Then I use BATT_MONITOR=9 to get the battery volt and ampere drawn. However since one esc reports a value of 25v and the other 4 around 50v I end up with a display battery value of around 45v ( (4*50+25)/5 ) which is neither the 6s package nor the 12s battery package voltage. I guess the currents are also added which is not correct.

Is there a way to specify which esc volt and amp to be accounted for battery 1 (e.g. the 4 copter motors of the VTOL) and also assign a 2nd battery and set the telemetry data from the forward flight esc only, to get the 6s battery volt and amp accordingly?

I have tried to isolate to a separate UART port the telemetry coming from the forward motor esc and set a BATT2_MONITOR=9 but then it doesn’t reported this esc telemetry neither the batt2 volt, amp in the MP.

I have Pixhawk6X and use Ardupilot 4.5dev (beta version from this link: Dropbox - Pixhawk6X-bdshot - Simplify your life, many thanks to Andy)

Thank you in advance for any hint and support. Happy to test any beta version if need be.