KDE ESC's & UBEC and Pixhawk not firing all motors

About two weeks ago I purchased six KDE 4215 motors w/ 15'' duals props, and KDE 55+ XF ESC's, and yes I am running a UBEC because of the isolated ESC's.  UBEC is running to main out port 7 & 8 on the servo rail.  I purchased these after seeing and flying them at Inter drone this year.  I fly a DJI S900 with Pixhawk.  Made the decision to get away from as much DJI hardware as I could, with the exception of the frame. 


- DJI S900 (Frame only)

- KDE 4215 Motors

- KDE 55+ A XF ESC's


- KDE 15' dual props

- Spektrum DX7 RC w/ satelite

- Neo 7 GPS / 3DR Ublox

- Max Amps 120C 9,000 mah 22.2V x 2



1.) Once armed, the motors will not spin up until given throttle input. Even when I do give throttle input, if I go all the way down on throttle, the motor spin down completely, it like being in stabilize mode, even though I have it set to Loiter mode.   

2.)Once armed and given throttle input the KDE motors seem to spin at different rates, some motors are a little faster and some are a little slower.  Also, motor number six will not come online until around 50% throttle, and when it does it's spinning much slower then the other 5 motors.  


I have done everything that I found on this and other forums with no luck yet

: properly set RC_MIN /MID/MAX 1100 -1520 -1900

: Integrate UBEC to run KDE ESC's


When I am connected through MP and run a motor test (Test all motors), all of them fire perfectly, but as soon as I have to fly through RC input, the issues appear.

There are quiet a few other headaches that I had to work through during this build, but I was able to resolve all of them myself, this one just seems to be a little beyond me presently. It seems that a lot of people using Pixhawk have 


had issues with ESC, and it seems like almost anyone that buys KDE ESC's has had issues running on Pixhawk.  I hope that I can get some advice from anyone who is willing to help, and that this discussion will help others that are experiencing similar issues, not to mention keeping them out of trouble with the Mrs. for constantly burning money.

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  • Eddie-

    I run the 75A KDE ESCs with a pixhawk and a taranis. I flash the ESCs using KDE's device manager. I set the calibration of the ESCs to "manual".  I am then able to calibrate the ESCs like a normal ESC, no messing around with the taranis or anything else. Just calibrate your RC radio like you normally would in mission planner, and then calibrate the ESCs (power cycle them with the throttle on the radio high, then disconnect the battery and reconnect).

    KDE has a document on their website detailing the setup of their ESCs with a pixhawk

    KDE ESC manual

    Let me know if you have any questions.



  • i did not set RC_MIN /MID/MAX in the parm list. but i did it when i done the radio calabration
    when you do the radio calabration adjust the throtle end points at both ends until you get the min max you want. i have a taranis radio and ended up with 76% and 79% of the travel on the throtle.
    hope this helps.
    these are fantasic motors and would not use anything else now, and so smooth and quiet with
    these props.

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