Hi,
Hope someone can help me with this problem.
My drone software says :motor overload, will decelerate.
After that, problem gone.
Only the drone is pretty unstable. So I guess at least 1 motor is not completely ok anymore. Last winter I had a little crash in the cold, wanted to film my ice skating kids from the air, but after take off, the drone made a loop and landed on its props. I guess it was too cold and 1 motor stopped. Replaced the props, and could not find any more damage, but maybe this has something to do with the current problems.

How can I find out which engine is bad?

Thanks!!

Do all the motors spin freely when turned by your fingers? Can you feel any sticking?

cheddar-man Posted at 8-28 11:29
Do all the motors spin freely when turned by your fingers? Can you feel any sticking?

They all feel ok. I can fly, but the drone is not as stable as before.

OK. Try calibrating the compass first and then the IMU. The Phantom 3 IMU calibration procedure is simple and takes between 5 and 10 minutes. The IMU calibration will fix most of the Phantom 3 issues including erratic flying, no signal and compass errors.
Heres the procedure.

cheddar-man Posted at 8-28 12:34
OK. Try calibrating the compass first and then the IMU. The Phantom 3 IMU calibration procedure is simple and takes between 5 and 10 minutes. The IMU calibration will fix most of the Phantom 3 issues including erratic flying, no signal and compass errors.
Heres the procedure.

OK. Try calibrating the compass first and then the IMU.
Why??
He doesn't have a problem with the compass or the IMU.
Unnecessarily recalibrating the compass and IMU won't do a thing to address his problem with the propulsion system.
Recalibrating things isn't a "fix-all" solution to things you don't understand.

Hi there. Thank you for reaching out and we're sorry for the trouble. As you had mentioned that you can spin freely the motors using your fingers without any issues. You may try to perform the IMU calibration on your unit as cheddar-man's suggestion as this might fix the stability issues on your unit. IMU calibration, which involves the accelerometer, will help set standards for the aircraft’s attitude and reduce errors caused by inaccurate sensor measurements, If your drone drifts a lot or is unstable when hovering, IMU calibration may help resolve the issue. However, please note that hovering isn’t 100% accurate, it’s normal for a DJI drone to drift a small amount, especially in high winds. You may refer to the thread below for your future reference, Tinus. Hope this helps. Thank you for your valued support!

https://forum.dji.com/thread-75438-1-1.html

Labroides Posted at 8-28 15:36
OK. Try calibrating the compass first and then the IMU.
Why??
He doesn't have a problem with the compass or the IMU.

Funny that DJI recommend the same Labroides!!! It would seem I "understand" more that you do

cheddar-man Posted at 8-28 23:39
Funny that DJI recommend the same Labroides!!! It would seem I "understand" more that you do

Funny that DJI recommend the same Labroides!!!
It's not funny at all ... it's the kind of nonsense I'd expect from them.
They suggest that whenever they have no idea about a problem, just as you did.
They are the last people you'll get good technical advice from.
I doubt that they even fly drones.
It would seem I "understand" more that you do.
Don't fool yourself.
The OP never suggested that his drone was drifting or unstable in hover.
Perhaps you missed the critical element in his post?

My drone software says :motor overload, will decelerate.

Goodmorning all, and thanks for the suggestions so far.
The calibration I already found in the faq, and did that, however I did not had much hope in that, because that would not stop the motor overload- pop-up.  And indeed, it did not help a thing. I can relate if 1 motor is bad, it won’t keep up with the other 3, and overload. If the others decelerate, problem solved. Also with 1 motor less good, it has problems to hover right. It is not a small wobble, it will raise and fall several meters every now and then. But sometimes it goes ok. Very hard to land. So it would be very helpful if someone could tell me if there is a way to find out which motor could be bad.

Thanks all!

Tinus08 Posted at 8-29 00:19
Goodmorning all, and thanks for the suggestions so far.
The calibration I already found in the faq, and did that, however I did not had much hope in that, because that would not stop the motor overload- pop-up.  And indeed, it did not help a thing. I can relate if 1 motor is bad, it won’t keep up with the other 3, and overload. If the others decelerate, problem solved. Also with 1 motor less good, it has problems to hover right. It is not a small wobble, it will raise and fall several meters every now and then. But sometimes it goes ok. Very hard to land. So it would be very helpful if someone could tell me if there is a way to find out which motor could be bad.

Maybe on way to find out is to fly the drone for a short while and land and feel all the motors, if one is warmer than all others...bingo

Obviously the argumentative sort Labroides read his post! "Only the drone is pretty unstable" and you say "OP never suggested that his drone was drifting or unstable'  
Oh well, I'll leave you to it...........

PowerBand1 Posted at 8-29 03:25
Maybe on way to find out is to fly the drone for a short while and land and feel all the motors, if one is warmer than all others...bingo

Thanks, will try that.

I thought in the past I saw an image of the motor loads etc in the software, but can not find that anymore. And back then I had no idea how to read those caracteristics.

You might consider something like this - see if it tells you anything useful:
  

Good luck

Tinus08 Posted at 8-29 04:39
Thanks, will try that.

I thought in the past I saw an image of the motor loads etc in the software, but can not find that anymore. And back then I had no idea how to read those caracteristics.

If you upload the .dat file from the drone it records all the motor parameters. It might show you something but bear in mind that to do a comparison of the motors that wouldn't show you much as when the drone is flying every motor is doing something different to keep it steady.
Like the idea of running the motors without props and checking temperature. Might show something.

cheddar-man Posted at 8-29 03:49
Obviously the argumentative sort Labroides  read his post! "Only the drone is pretty unstable" and you say "OP never suggested that his drone was drifting or unstable'  
Oh well, I'll leave you to it...........

Obviously the argumentative sort Labroides
So it's being argumentative to try to help the OP and point out that some of the "advice" he's been given is uninformed bollocksand of no use at all for the problem he's described?

read his post! "Only the drone is pretty unstable" and you say "OP never suggested that his drone was drifting or unstable'  
He gave enough information to make it clear that it's unstable because it has a motor problem, not because the compass or IMU needs tweaking.
Pretty well any time someone suggests recalibrating the compass and IMU, it's a safe bet that they have no idea what the problem is or what might fix it.

Tinus08, just ignore all the negativity and as the manufacturer suggests, just do an IMU calibration, costs nothing, just a bit of time. It might sort the problem, it might not.

If it doesn't then you're into checking out each motor possibly, remove them and check for problems. The fact you landed on the props it's possible a shaft has bent slightly. To check this, put the props on and look at the tips as they rotate, you should see just one line, not two, one above the other.

cheddar-man Posted at 8-29 05:12
If you upload the .dat file from the drone it records all the motor parameters. It might show you something but bear in mind that to do a comparison of the motors that wouldn't show you much as when the drone is flying every motor is doing something different to keep it steady.
Like the idea of running the motors without props and checking temperature. Might show something.

How can I upload (find) the .dat file?

Thanks all for the suggestions. I will try to find the .dat file, try the temp option without props, and try to find an optical rpm camera.
I will keep you all updated!

If you look at the front of the drone you'll see a little USB port? Connect it to your computer and you can access the .,DAT files stored on the internal memory.

cheddar-man Posted at 8-29 06:41
If you look at the front of the drone you'll see a little USB port? Connect it to your computer and you can access the .,DAT files stored on the internal memory.
[view_image]

Thanks. I’m on holiday atm, I will do this next week when I’m home. Can I upload it here? Or can I myself see anything in it?

You need to CsvView here and then learn how to upload your .DAT file to it and then plot the required data, in your case the motor data.

Alternatively you can upload the .DAT file here and some kind person will have a look at it.
Don't know what computer you have? Accessing the .DAT files with a PC is easier than with a Mac.

finally some time to dig into this problem. I tried the trick with running the motors without props, but unfortunately the motors only run for a short period, and stop with an error.
Tried to feel the engines after flying, but no noticable difference in temperature.
also calibrated the imu. all no succes.
now downloaded the .dat files.  i added a link to download it for the people that wants to help me and know how to read it
thanks in advance, hope someone can help me.
http://gofile.me/6Io1z/Db3UrTJvl

If you've downloaded your dat file, you now need to convert it to a useable and readable format.  You can do that by downloading a program from datfile.net and use it to convert your dat file to csv.  After you convert the file to CSV, you can then view the data yourself with a text editor, or better yet, with a spreadsheet program such as Excel.  You can then view the columns showing each of your four motor data and try to find a discrepancy.  Good luck.