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Pumpkin drop event

EMAX ESC compatibility with Pixhawk.


Junior Member
I have been working on a tricopter using the FliteTest power pack. I have gotten to the point of testing the motors on the flight controller and cannot get the EMAX ESCs to initialize. I have made sure the arm button is solid, calibrated the Tx, double checked that the FMU is arming, it is in stabilize mode, I can get the ESCs to initialize on a servo tester, or off the Rx, but on the Pixhawk I get nothing whatsoever.

I did some digging and came across a few threads of people claiming that EMAX ESCs will not work with Pixhawk because the voltage on the servo rail is 3.3v instead of 5 and the ESC draw pulls that down to 2.8v or 2.2v I don't know how accurate that is, but I was hoping somebody on these forums might have found a work around and/or possibly run into it and discovered they were just overlooking something.

Here is some links to other people describing the exact problem I am seeing.





After some more tinkering I pulled out my spare MRM 12a BLHeli ESC and tested it with the Pixhawk. Sadly it worked great. The MRM ESC is running BLHeli 13.1 I am not sure about the EMAX ESCs from the power pack because the USB linker won't talk to them.

Kinda bummed I had to buy 5 more ESCs to finish this build, but on the bright side I will have 5 20a ESCs to make scratch builds with!

TLDR; Avoid the EMAX ESCs if you plan to use a Pixhawk.
Last edited:


Senior Member
thanks for the tip. i would of never guessed a ESC would not be compatible with a FC. i wonder what the fix would be. if the ESC could be flashed, i guess maybe a new version of Bheli, or simon.. but from what i understand some of the Emax ESC can not be upgraded?

but i can say the Emax ESC i have work great on a quad. so yeah you may of had to buy more.. at least you have a set now to start another build.. one less thing to buy.. i always try to look at the issues i have in a positive light. not always easy.. but sure makes life easier to get through. LOL



Junior Member

Problem – Pixhawk not initialize ESC
My Pixhawk (firmware 3.3.3) controller will not initialize the ESCs on my home made QUAD.

I setup the Pixhawk origallialy on a HobbyKing Turnigy SK450 Quad with Multistar 20amp sbec and Multistar 2213 – 935kv motors and it worked fine.

Now when I moved the Pixhawk to this new quad (EMAX BLHeli 20amp ESCs and EMAX 2213 935kv motors) the Pix starts up ok but the ESC/motors never give those initial beeps. I have tried resetting the throttle end points 1000 to 2000 in Mission Planner software – no joy.
I have tried to teach the Pixhawk the throttle range (program the ESCs – power up the Pix with throttle in high position ) but no programing beeps from ESC/motor.
I am stumped – why does the PIX not talk to my new ESC/motor combo?
I am planning to move the PIX back to the Turnigy SK450 just to prove that I have not lost my mind.
Kindly help and old man (72).