Honey Badger - #3 Motor issue (video)

[kerrycorcoran]

New to RC and multirotors. Purchased a Honey Badger and all seems fine, however I am running into an issue with the quad dropping or losing power on the #3 motor.

Basically it'll fly fine, then all of a sudden it will dip hard in the lower right corner, not necessarily crashing, but a definitely hard motion. I have been trying to isolate the symptoms as much as possible and when it happens I land it and felt all motors and ESCs, all feel fine - nothing seems overly heated.

Components:
StrongRC Motor KEDA KA20-26M
RCMC 20 Amp SimonK ESC's
KK2.1 Flight Controller

Here is a video of the behavior. Notice after it has the issue #3 won't spin up properly, its almost acting as if its trying to spin both CW and CCW, which it should only spin CW. Eventually it starts spinning normal and takes flight again.

When the issue isn't happening I can keep the HB in the air with out issue. I know this is not pilot error.

Any help appreciated.
Thanks,
Kerry

 

[fengshuidrone]

Looks to me like a wiring issue or an ESC calibration issue. Intermittent shorting or a loose connection in the wiring is the most likely cause in my humble opinion.

 

[kerrycorcoran]

From a physical observation I have reviewed all the wiring and its all snug, clean and heat shrink in place. I am leaning toward ESC calibration as well. Yesterday, before I flew it I performed a ESC calibration with the help of my wife. I don't think she held the buttons down the entire time. About an hour ago we did another ESC calibration, this time I held the buttons and she did the throttle up/down - I saw messages as the calibration went through the process.
Unfortunately I won't be able to test this until tomorrow.
Will post an update once tested.

Thanks,
Kerry

 

[fengshuidrone]

From a physical observation I have reviewed all the wiring and its all snug, clean and heat shrink in place. I am leaning toward ESC calibration as well. Yesterday, before I flew it I performed a ESC calibration with the help of my wife. I don't think she held the buttons down the entire time. About an hour ago we did another ESC calibration, this time I held the buttons and she did the throttle up/down - I saw messages as the calibration went through the process.
Unfortunately I won't be able to test this until tomorrow.
Will post an update once tested.

Thanks,
Kerry

It's the running backwards thing that puzzles me the most. The way it flies perfect until the symptoms happen makes me think it is wiring related. Usually, bad ESC calibration results in an unflyable condition. Some loose connection on the FC like a loose fitting connector on an input pin or something similar just seems to be the most likely cause. It's like the signal from the FC is being interrupted temporarily or something like that. It is the intermittent nature of the symptom that makes me doubt the ESC thing. A badly calibrated ESC will be badly calibrated all the time until you fix it, not working perfect some of the time and not working some of the time. ESC calibration issues are related to throttle differences between calibrated and uncalibrated ESCs, meaning that the uncalibrated ESC does not know min and max throttles and would most likely never sync well enough with the calibrated ESCs to get the quad in the air.
I hope your re-calibration works and I am wrong.

 

[kerrycorcoran]

Yea, its definitely a mystery. The actual video when taken was over 6 minutes, I cut out the first 3 minutes as there wasn't ANY symptoms of issue. Thought may it had to do with length of time in flight, lack of power, etc - I am new and trying to eliminate anything I can think of. Then I charged the battery again and ran for a solid 7 minutes without a single issue. Tried again, symptoms again. Its weird.

What can cause a motor to reverse rotation? From what I have read, the only way to reverse direction is by swapping any 2 of the 3 wires that go to the ESC. I wonder (like you say) if something is shorting the motor wires; question is would that cause that symptom?

 

[fengshuidrone]

A simple bad bullet connector connection could cause the motor to run backwards. A cold solder joint. Goes from 3 phase to 2 phase when that happens. I think that would cause a temporary reversal, but I am not positive on that.

 

[kerrycorcoran]

I have a motor and ESC; but wonder if I would fry them trying to test it out. How would I test it out too? Get the motor going and run a jumper between to connectors?

 

[fengshuidrone]

Just try unplugging one wire while it's spinning I guess. It will either run backwards and then stop or just stop. I have never had to do anything like what you want to do so I must qualify my advice with a "you are on your own" statement when it comes to these tests.

 

[kerrycorcoran]

It would appear that is the issue. When the motor is spinning and I pull one of the 3 wires it immediately goes into a staggered state, clicking back/forth attempting to spin CW and CCW. Never makes a rotation, just clicks sporadically.

This means now I have to try and find the shorted wire/connection. Boo.

Appreciate the help!!

 

[kerrycorcoran]

Before I go that route, is it possible the power (battery) wires could cause some issue or interference? When I got the HB the power leads were a different connector than the battery I had. I snipped off the connectors and replaced with what matched my battery. I soldered and heat shrunk and all seems to work as it should. That said, that changed the routing of the power leads, not by much, but it is different than how it was. See pictures.

Think that would make a difference?

 

[fengshuidrone]

IMHO, no. It really sounds like a janky motor wire or motor to ESC connection. Cold solder joint or broken wire inside the insulation. Now that I looked a little closer, I realized that the motor that is cutting out is the one near your re-route. I see the battery wire is resting on the ESC. Check to make sure there is no wear through at that point. Also check the ESC to motor wires on that ESC. See if you can see down in there where the wires attach to the ESC under the shrink wrap.I also see there is a pull tie pulled tight right where the ESC motor wires attach to the ESC. I am suspecting this might have pulled two wires close enough to come into contact even if just barely, or even caused one of the wires to just come loose from the ESC. The shorting of the two ESC to motor wires could I believe actually cause the reverse thing that you had going on. Also upon closer examination I see all of your ESCs are held on with tie wraps at the wire and ESC junction. I would move the tie wraps to the middle of the ESC where the heat sink is.
My reasoning is that maybe when you re-routed the battery wire the added stress from the wire resting on the ESC has caused the tie wrap issue to exacerbate the connection problem.

 

[kerrycorcoran]

I took the top plate off, exposing all the wiring, and wiggled and pushed on all connections...not a single issue. Surely as much as I was wiggling and poking around I should have seen the issue, one would think.

Something odd I noticed, or maybe not odd, but this doesn't have a power distribution board. Is that common?

 

[kerrycorcoran]

I decided to try another ESC Calibration; it worked. Since the 2nd calibration I haven't experienced the issue at all.

It is possible I did not properly perform the initial calibration.

The HB is flying perfectly now.