I am wondering if you have ever tried to opto isolate the pwm signal going to BESC30?
I am presently working on a design where the power and control side will be isolated with an ISO DC-DC converter and I realized that the BESC-30 signal will be reconnecting my 2 “grounds”.
We actually did have some opto-isolators on a revision of our BlueESC at one point. We did run into one major issue.
The switching speed of optoisolators is fairly slow, especially when you don’t drive them with much current. The Pixhawk autopilot has current limiting resistors on each PWM line to protect those lines. I believe the resistors are 1k and the PWM voltage is 3.3v, so the drive current is 3.3mA max. With that amount of current, the switching was very slow and changed the length of PWM pulses such that the range of signals was skewed. If you connected it to a device that had more current, the range would be normal.
We ended up removing it because we couldn’t manage to get predictable performance in all situations.