The lights are on but nobody is home

I remove the thrusters from the system. I have a job for just a camera. No room in the boat for the ROV and tether, etc… After putting everything back together basically I have the electronics enclosure alone and it is powered from a battery on the surface. I am using a 6 meter cable. Anyway I don’t have telemetry. Considering there is no way disconnecting the thrusters should effect telemetry is there anything I am doing wrong. I have nothing on QGC.

What voltage are you applying, and what guage is the cable? What is the voltage at the electronics? Do you see video?

I am using a BR battery. I am seeing 15.0 volts at the terminal strips. No I don’t see video. The cable is a section of BR tether. I am using 3 TWP for power over 6 meters.