Mavic Pro Motor Mod

efowler · May 25, 2018

Just saw this thread for the first time. Thanks for the tip beanbubba, -
Nice discussion everyone. I am impressed by the cool engineering going on! Very compelling reading!

chazz · May 25, 2018

I took mine out for a flight and it din't go so well. I don't know if its the new motors or the props or what but as soon as it took off there was a rattling noise and it flew left fast. I couldn't shut it down i had to pow it into the grass. Then it sat there convulsing. i'm going to take a few steps back and put the phantom motors back on to see if i can get it to work like before...

chazz · May 25, 2018

Changed to the p3 motors and there's something not right. About every 5 sec during hover it tilts towards to the left front and makes some kind of noise. I don't know if the esc got damaged or one of the motors is messes up but the last thing I'm trying with this before it becomes a paperweight is 4 new p3 motors...

beanbubba · May 25, 2018

chazz said:
Changed to the p3 motors and there's something not right. About every 5 sec during hover it tilts towards to the left front and makes some kind of noise. I don't know if the esc got damaged or one of the motors is messes up but the last thing I'm trying with this before it becomes a paperweight is 4 new p3 motors...

Carefully re-solder the motor leads. Mine had a clear coating that was not easy to extricate and caused power problems. Not sure if I had cheap china knock off's or what the deal was.

lolo780 · May 25, 2018

chazz said:
Changed to the p3 motors and there's something not right. About every 5 sec during hover it tilts towards to the left front and makes some kind of noise. I don't know if the esc got damaged or one of the motors is messes up but the last thing I'm trying with this before it becomes a paperweight is 4 new p3 motors...

Pull the .dat file to see if it's a software or hardware issue. Google drive and post the link if you want some second opinions.

beanbubba · May 28, 2018

beanbubba said:
Carefully re-solder the motor leads. Mine had a clear coating that was not easy to extricate and caused power problems. Not sure if I had cheap china knock off's or what the deal was.

Chazz,

THANK YOU for those micro banana connector leads !!

That fixed all the nagging motor issues I was having in this mod. There is something unique about the p3 motor wire leads but they stick perfectly to the banana connectors you recommended.

I also found out thru trial and error the the startup DJI "chime" is exactly as Lolo said and is the ecs giving audible validation that the electrical connection to the motors is up to spec. If you remember that I was puzzled why the chimed stopped early in testing this mod, it was because I had a really bad connection. Well, later testing I improved the motor wire connection but still not perfect and the "chime" was barley audible. Then I installed the banana plugs and the "chime" came back full volume.

You learn sumthin new every day in this crowd!

In summary, if you try this mod and the power-on DJI chime is not loud and clear, re-check all your motor wiring.

beanbubba · May 29, 2018

I finished all 4 rotor arms and gps extender (3d printer files are attached). I also procured some longer M2.5 screws (20mm, I think) that securely lock in the new rotor arms and are easily removed and you can put the factory arms back on if you desire.

chazz · May 29, 2018

Hey beanbubba that's awesome man! Where you able to do a test flight? I'm curious to see if you have the same issue as me. When it weights 1400 grams im able to fly but if i go down and up fast the front left motor and arm vibrates and it tilts towards that direction. When i check the data file that motor has higher amps then the rest. 7 to 9amps compared to 4 to 6...if i go to 2000grams it happens as soon as i take off.
i'm still waiting for the motors having some shipping issues,,,

beanbubba · May 29, 2018

chazz said:
Hey beanbubba that's awesome man! Where you able to do a test flight? I'm curious to see if you have the same issue as me. When it weights 1400 grams im able to fly but if i go down and up fast the front left motor and arm vibrates and it tilts towards that direction. When i check the data file that motor has higher amps then the rest. 7 to 9amps compared to 4 to 6...if i go to 2000grams it happens as soon as i take off.
i'm still waiting for the motors having some shipping issues,,,

No flight yet. I have all 4 motors spinning on the bench. I have 8 hours left of 3d rotor arm printing left. I had some printer failures the last 2 days and behind schedule.

EDIT: I have noticed from the multiple trial and error that the solder point on the main board is a big factor too. Make sure that solder point is as high of quality as the others.

chazz · May 30, 2018

I re soldered to the board and still no joy. Hopefully i just have a lazy motor or two. Still waiting for the package the post-office said it delivered.

beanbubba · May 30, 2018

chazz said:
I re soldered to the board and still no joy. Hopefully i just have a lazy motor or two. Still waiting for the package the post-office said it delivered.

I have been non stop googling on this topic and found multiple references to soldering too close to the motors and ruining the magnets in the motor. No idea if this holds water but many folks are talking about it.

I was very sloppy and was soldering literally right on top of my motors and now 2 are acting up.

The motors are cheap enough, I ordered a new set and will be extra careful when installing my new 3d printed rotor arms just to rule this possible issue out of the equation. New motors arrive Monday, so no updates from me until next week.

chazz · May 30, 2018

I didn't know of that issue and its good to know but i think I've been pretty careful with what I'm doing but who knows. I definitely could have messed something up and actually hope I did so i can cure it with the new motors

... I changed some battery limit parameters to match the p3 but didn't work.. If the new motors don't work, as hard as it may be, I may have to give up unless lolo figures something out with the data logs...

chazz · May 30, 2018

This is an example of what the current and speed of the left front motor looks like compared to the others when or maybe right before its happening. 9 amps at 7200rpm. The only other motor i can switch with it for now is the one i have on the rear right that had pieces of propeller stuck in the windings.

beanbubba · May 30, 2018

I have an unsubstantiated theory that soldering too many times directly on the main board will damage something with all the excessive heat. In the future when I am doing these mods that require to re-solder to the main board several times, I will solder once and attach those micro banana adapters.

beanbubba · May 30, 2018

chazz said:
I didn't know of that issue and its good to know but i think I've been pretty careful with what I'm doing but who knows. I definitely could have messed something up and actually hope I did so i can cure it with the new motors ... I changed some battery limit parameters to match the p3 but didn't work.. If the new motors don't work, as hard as it may be, I may have to give up unless lolo figures something out with the data logs...

I hear you. If my new set of motors don't pan out, I will most likely abandon this mod too.

But even if this doesn't work out, I have created some super light weight rotor arms to use with the factory motors. So not all will be for naught

chazz · May 31, 2018

Changed the left front motor today and same thing no change. When i go down and up full throttle it vibrates the left front arm and makes a sound like the prop is hitting something but it isn't..I tried loading the firmware again just to try that and still same thing. I was surprised the parameters that originally i had changed were not changed back to factory default after loading the firmware again. Anyone know if this is normal? Here is another pic of a short flight showing the current to all the motors. It's almost hard to believe at 89 sec all the current is going to one motor. I think its a waste of time to change the rest of the motors.

lolo780 · May 31, 2018

I have an idea for you to try.

Bypass the shunt on the ESC board and run power/gnd direct to the FETs. You'll get missing prop errors and no current readings, but that will eliminate the possibility of any overcurrent software protection limits. I've run external battery mods this way before to eliminate resistive losses, but not having the watt second logging makes it difficult to tell.

chazz · May 31, 2018

It's really driving me nuts i cant imagine why its picking this one motor to mess with me...but yes can you show me a pic of where to solder the leads please?