Holybro Tekko32 F3 ESCs sporadically not starting

I have an issue that some of my ESCs fail to start sporadically. When this happens some of the six ESCs do not light up and do not respond to throttle input. If they startup, they work flawlessly. I did calibrate them. I use PWM. I could not identify any shortage or loose cables.

Did someone experience similar issues with BLHeli_32 ESCs?

What version of ardupilot are you using?

Hi @andyp1per,

I’m using 4.07 and BLHeli_32 32.8.

It happens sporadically and I could not reproduce it, but it happend again today. When I connect an disconnect the power 25 times it might happen 1 time.

Could it be an issue of a initial voltage drop when connecting the power to “slow”? It’s a 4s system.

I have read within the EMLID forum that it might help to reduce the PWM speed (RC_speed) from 490 to 250 because this is a whole fraction of the native ESC speed. Any thoughts about that?


Tekko32 F3, F0, Wraith32 Mini and v2… never encountered such issue.

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There are certainly issues with BLHeli32 ESCs arming when using dshot depending on board/ESC, but I don’t know whether it should not affect PWM.

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I found this and I think this describes the issue.

What I find hard to understand is why, if it happens, several ESCs are affected and not only one. So there should be another cause for that I think.

Is it possible to enable DShot 150?

Not sure if a temperature related oszilator drift could cause this problem…

No, the ESCs are conected to the standard ports and I cannot change that.

Since I did not notice this problem during many test when it was relatively cold and it started when it was warm and sunny temperature might be an factor.

I’m looking now into the possibility that the ESCs change into bootloader at startup because of an issue with the initial state of the PWM outputs.
I wonder if:

  • the initial state of the outputs can be different for each output, because motor 5 and 1 always seem to start correctly.

  • how does a BRD_BOOT_DELAY influence the initial state. Are the outputs undefined during the delay period?

  • could the parameter MOT_SAFE_DISARM help to make the startup more reliable?

I also did notice an issue with the ESC calibration procedure, all of my ESCs from different brands fail to calibrate reliable with PWM values below 1100 and above 1900.

ESC calibration is 2017 or before, back in the realm of 8-bit ESCs and old algorythms. I uncheck throttle calibration from BlHeli32 configurator on all my ESCs.

What FC are you using !? I’ve matched BlHeli32 ESCs with alot of platforms, from clone Pixhawks to CUAV Nora and I have never encountered an abnormal ESC initialization.

As far as I know non PWM solutions where buggy until recently. So for me PWM seems still an attractive and proven solution. Anyhow I need relay and camera feedback functions and I’m therefore unfortunately not able to switch to dshot, I think?!

I use a mRo X2.1. I think it is ESC related. I now think there might be a combination of ESC settings which cause the issue.