MOTOR SPEED ERROR MAVIC MINI

SSG Rock · May 20, 2020

Only had my mini a few days now (50 Min). Flew awesome, did the 500 upgrade yesterday and this morning three min into a flight... motor speed error, left rear. Always careful storing in the case..... ???? And the ads show people carrying them around in their pockets?

21st today. Ran assistant 2 on C/A to refresh the 500 yesterday. Weathered out until this morning and went for a ten minute flight around the property. Not a hint of a problem. Confused?

dap455 · May 22, 2020

Noah McDonough said:
I have not downgraded yet. Waiting for appropriate weather to try out the new rotor blades in the field.

Thanks, would love to know your results

SSG Rock · May 23, 2020

dap455 said:
Thanks, would love to know your results

I didn't downgrade, just did a refresh on the .500 upgrade. Had pretty good weather yesterday and put another 30 min. on her and no problems at all.

dap455 · May 23, 2020

SSG Rock said:
I didn't downgrade, just did a refresh on the .500 upgrade. Had pretty good weather yesterday and put another 30 min. on her and no problems at all.

Interesting..thank you, will have to try..

cosmictrucker · May 23, 2020

As others may have reported, exact same issues with LR motor due to originally updating firmware via the phone. Downloaded the Mavic 2 for PC , signed into my account, powered on the drone with arms out and plugged in the USB cable to the PC and performed the downgrade, then powered the drone back up and performed the upgrade to 5.0 via the PC. After a solid test flight experienced no issues. I'll perform all updates via the laptop from here on out.

cosmictrucker · May 23, 2020

Noah McDonough said:
I've been intermittently getting the motor speed error for the rear left rotor (drone front facing away from me). I do have the flymore kit and thought it might be damaged rotor blades. I ordered a new set of rotors and upon installing them I noticed that the rotor in question does seem to move less smoothly than the others. when rotating counter clockwise it seems to stick a bit. Anyone seen this or have any recommendations?

Same here, after swapping blades and still having this warning issue I took a closer look at the motor. I also thought that the left rear motor rotated more notchy than the others. If I put a little pushing pressure or pulling pressure the motor seems to turn more smoothly. I was thinking I had a bad motor with a bad bearing or something. But, after reading about using the app to use your PC to perform the firmware updates, I found that by doing this my problems seem to be resolved.

Mangelo · May 24, 2020

ok so its the props !, no its the motor! , wait its the firmware! , and its back , motor speed error on both SHORT flights yesterday

I read through this thread and still dont know how to resolve this issue , anyone ????
whats crazy is I had no issues for multiple fights a couple weeks back (the problem disappeared) after a short time in storage , full blown motor speed errors again , oh wait it the case !! or ....................

sar104 · May 24, 2020

Mangelo said:
ok so its the props !, no its the motor! , wait its the firmware! , and its back , motor speed error on both SHORT flights yesterday I read through this thread and still dont know how to resolve this issue , anyone ????
whats crazy is I had no issues for multiple fights a couple weeks back (the problem disappeared) after a short time in storage , full blown motor speed errors again , oh wait it the case !! or ....................

Seriously - you have read this and other threads and you don't know whether it's the props, the motor or the firmware?

gymnast46 · May 24, 2020

Mini is less than a month old. Motor Speed error occurred after a couple of weeks. I replaced the props in the left rear. Today, the same thing! This is getting old.

cosmictrucker · May 24, 2020

gymnast46 said:
Mini is less than a month old. Motor Speed error occurred after a couple of weeks. I replaced the props in the left rear. Today, the same thing! This is getting old.

Have you tried using your PC to reflash your firmware? This seems to have resolved my issue. Instructions are in past feedback

Noah McDonough · May 26, 2020

Flew for a decent amount of time with the new rotors and I didn't get the motor speed issue. If that keeps up, I'm going to say it had to do with me storing the mini improperly in the flymore case.

Mr Curry Lover · May 31, 2020

FIXED ISSUE (and it's nothing to do with the case)
I had the exact same problem as everyone else, I even changed the props twice and managed to book my drone in for sending back to DJI but before I returned it I decided to have a play around and I managed to resolve the issue. I have been running the latest firmware for a few weeks and not had the issue once.
Here's the instructions for fixing the issue.
1. Download and install the DJI Assistant for Mavic 2
2. Connect the drone to your computer and upgrade to the latest firmware. (I first downgraded).
3. Replace the drone battery and do the firmware upgrade again, do this for every battery that you have.
4. Now plug your controller in and upgrade the firmware on this.
5. Once all firmware upgrades have been done connect your phone to the controller and power everything up (don't unfold the arms)
6.

Tap on the 3 dots in the top right corner of the DJI Fly App.
Tap on “Safety”.
Scroll down to the Sensors section.
Select Calibrate to the right of the IMU.
Click on “Start and follow the onscreen instructions to orient the drone for IMU calibration.
Start with the Mavic Mini on its belly and the calibration will go to 100%. The LED will flash green when complete.
Next, move the Mavic Mini onto its right side and the IMU will calibrate to 100%. The LED will flash green when complete.
Change the Mavic Mini over to the left side and let it calibrate to 100%. The LED will flash green when complete.
Stand the Mavic Mini on its back end and let it continue to calibrate the IMU to 100%. The LED will flash green when complete.
Turn the Mavic Mini upside down so that it’s camera is pointing upwards and let it continue to calibrate.

7. I did the above steps and the fault hasn't returned and I never sent the drone back to DJI

sar104 · May 31, 2020

Mr Curry Lover said:
FIXED ISSUE (and it's nothing to do with the case)
I had the exact same problem as everyone else, I even changed the props twice and managed to book my drone in for sending back to DJI but before I returned it I decided to have a play around and I managed to resolve the issue. I have been running the latest firmware for a few weeks and not had the issue once.
Here's the instructions for fixing the issue.
1. Download and install the DJI Assistant for Mavic 2
2. Connect the drone to your computer and upgrade to the latest firmware. (I first downgraded).
3. Replace the drone battery and do the firmware upgrade again, do this for every battery that you have.
4. Now plug your controller in and upgrade the firmware on this.
5. Once all firmware upgrades have been done connect your phone to the controller and power everything up (don't unfold the arms)
6.

Tap on the 3 dots in the top right corner of the DJI Fly App.

Tap on “Safety”.

Scroll down to the Sensors section.

Select Calibrate to the right of the IMU.

Click on “Start and follow the onscreen instructions to orient the drone for IMU calibration.

Start with the Mavic Mini on its belly and the calibration will go to 100%. The LED will flash green when complete.

Next, move the Mavic Mini onto its right side and the IMU will calibrate to 100%. The LED will flash green when complete.

Change the Mavic Mini over to the left side and let it calibrate to 100%. The LED will flash green when complete.

Stand the Mavic Mini on its back end and let it continue to calibrate the IMU to 100%. The LED will flash green when complete.

Turn the Mavic Mini upside down so that it’s camera is pointing upwards and let it continue to calibrate.

7. I did the above steps and the fault hasn't returned and I never sent the drone back to DJI

That's great, but represents correlation, not causation. Multiple tests have confirmed the exact manifestation and cause of the issue. It's the props, not an IMU calibration problem.

Mr Curry Lover · May 31, 2020

sar104 said:
That's great, but represents correlation, not causation. Multiple tests have confirmed the exact manifestation and cause of the issue. It's the props, not an IMU calibration problem.

I'm sure that it's worth further investigation though. It may be the firmware upgrade on every battery. It may be the calibration or it might just be fluke but before I did the above I got the error every time and now I am using the same props with the latest firmware and I haven't received the error once.

rehkram · May 31, 2020

Are you thinking that the IMU was slightly off and spuriously reporting the need for more power to one or more motors to bring the craft back into trim?

lowellton · May 31, 2020

FoxhallGH said:
This sounds a bit like part 1 of the 'uncommanded descent' issues being discussed in other threads. It might be that the firmware upgrade is coincidental - but ... A couple of questions and suggestions:
1) Have you noticed any difference in the sound of the drone? i.e. does it sound like it's rpm is higher??
1a) If you have a second set of prop's and can change the REAR set of 4 blades only, does that change the flying sound to a lower pitch [rpm]?
2) Have you noticed any difference in the stability of the drone in the hover? Does it hover steady, or wobble about a bit??
3) Fold out the MM's arms and prop's, and looking horizontally at the prop blades - do the front set have a different shape to the back set?? i.e. do the props on the back look a bit 'flattened'?
4) Do you store the MM folded up in a Fly More case?
5) If the answer to 4) is Yes - do you make sure that the prop blades on the rear arms are lying east/west across the body of the drone, or do they angle back toward the rear of the drone when it is packed in the foam cut-out?

There have been reports of the MM being stowed in the Fly More case with the [rear] blades that end up on the under-side, angled back toward the rear of the drone. If that happens, the drone will sandwich the blades under itself. A foam block on the lid of the case puts added pressure through the Mavic down onto the blades sitting on top of another foam block under the MM. It seems that if this stowage is not done carefully, the blades on the rear arms, can get 'flattened' and lose some of their pitch. That then means they have to over-rev to get the same lifting ability. It's possible that the over-rev can also make the blades stall and lose all lift, making the MM descend.
Ideally, when in the Fly More case, the rear prop-set should sit free in an open space in front of the foam block that supports the belly of the Mavic.

I'm wondering if the motor speed warning is the first stage of this problem that has been seen by a few Mavic Mini owners.

I got the same message before but now i havent seen that.

Mr Curry Lover · May 31, 2020

rehkram said:
Are you thinking that the IMU was slightly off and spuriously reporting the need for more power to one or more motors to bring the craft back into trim?

It's plausible and worth further investigation. It would be worth other people with the same issue trying the fix and see what results they get

rehkram · May 31, 2020

Plausible I agree. I don't know enough about the IMU outputs + FMC s/w responses thereto to comment at all knowledgeably.

sar104 · May 31, 2020

Mr Curry Lover said:
I'm sure that it's worth further investigation though. It may be the firmware upgrade on every battery. It may be the calibration or it might just be fluke but before I did the above I got the error every time and now I am using the same props with the latest firmware and I haven't received the error once.

But what are you proposing the IMU has to do with this? The IMU data are what show that the problem is occurring, so that doesn't make any sense to me.

rehkram · May 31, 2020

It might though. Pure speculation on my part but what if the IMU error was below the threshold triggering an IMU recalibration message. So up we go. IMU reports in-flight out of trim, FMC responds, gunning one or more motors. No effect so it increases power until motor overspeed threshold is reached and triggers the warning message.

Somewhat supportive of this scenario are the are reports of the overspeed error occuring after a prop change, if I'm not misremembering that.

It could also be just a bad case of wind upsetting the trim. There are so many permutations it's hard to nail down without so much as a system diagram, let alone the code. Could be a combination of several errors, in fact I'd bet good money on that, the swiss cheese model strikes again. As a result I'm not expecting a fix anytime soon.