I have a problem with Pixhawk plane wired and power as it says in manual with secondary backup power source and Zener diode. The plane was flying well while all autumn but at subzero temperature (-5C to -15C) the plane shuts down the motor in mid air.

 

I fly missions 60-80 min long. It shuted down the motor while first mission, I have changed motor and ESC. 3 missions later it crash again. I did test on the ground, and the motor would turn off after 5 min runnig. I turned the plane on in the office and this is what I saw: https://youtu.be/HMyRHtuzHXk

 (In the video the motor changes rpm by it self).

The motor start to spin, stop, working very in osculation way, or just spin. The way I fixed it, changed throttle output to port 6. It worked for another 3 missions, then changed to port 7 and so on.  So I thought that that something burns out in output port but yesterday I changed throttle back to port 3 and it worked well. Servos connected to PWM 1 and 2 work fine, the problems follows the throttle signal wire. I also get very bad compass variance and ARHS as soon as GPS gets 3D FIX, even after calibration.

 

All this problems appeared after I build new plane but with LIDAR-lite connected via PWM and updated to the latest Arduplane so it could support LIDAR.  

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              • Developer

                This log 46 again, you can see the autopilot is commanding full throttle when you say it cuts out and the alt drops. The ESC is faulty. I would suggest trying with another one. The other logs don't show RC in or RC out so it's hard to decipher what is happening on the bench3702912379?profile=original

                • Could it be static? When there is enough static electricity accumulated ports go crazy? And when I change it to different port there is no static and everything work well till static accumulates on that port again?

                  • Hello! Did a test today. with Lidar disconected. Plane shuted the motor again, I swithed to FBWA, gained some altitude then switch to AUTO, plane flew for a bit and then shuted motor again so I had to swith to FBWA in then land it. So I guess this mean that ESC is working properly? Seems like problem inside settings or somewhere in Pixhawk... 

                    here is full log of todays flight.

                    https://www.dropbox.com/s/s8jn03y1q15din8/102_test1.BIN?dl=0

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              • I will attach log for the video above.

                Could it be some kind of noise that makes ESC go crazy?

                _47.BIN

                _48.BIN

  • That sounds like your ESC is overheating to me.

    If the ESC doesn't have "active freewheeling" it will actually heat up more during partial throttle operation.

    I recommend you try an ESC with that feature.  (I use the YEP 80A escs on all of my big FPV planes).

    Alternatively, you can try adding a large external heatsink (I cut up one from an old desktop PC CPU) and loading simonk firmware onto your ESC.

    It could also be that the cold outside temperature is causing some sort of overflow in the firmware of the ESC causing it to go into thermal shutdown when it's actually cold instead of hot. If so, the SimonK firmware will probably fix that also.

    • I use Castle talon 90A. I thought it could be thermal shutdown but then why did it go crazy on video when I turnd it on in the room?

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