Dji Crash

[carlert]

Hi, i recently built a standard DJI F550, with the 2212, motors, DJI NAZA with GPS, DJI 30A ESC and so. I Calibrated it and so and i flew a couple of testflights, maximum a minute each time and it worked great. So i decided to mount my gimbal and camera to take it for a longer flight.

I have full GPS lock and so and after about 2 minutes the machine runs way more on one or to motor and the machine crashed in the ground. It was not very high. i flew in GPS mode. Minewhile i have just starded a new build, a Droidworx XM-6 with wookong. I just 100 procent different gear, eaven other batteries and a different radio and reciver, the ONLY thing that i used from the crashed F550 was the DJI 30A ESC. And it crashed the same way as the F550. Can it be the ESC. It has to be but the ESC´s works when i test without propps but the two machines crashed on the same way.

F550 crash: http://www.youtube.com/watch?v=7NEQ10kWxp8

Droidworx crash: http://www.youtube.com/watch?v=wt-b8vPEfgA

I have video from the both crashed. Not great footage but mayby som idea?

 

[ChrisViperM]

Looking at the vid from the XM-6, it looks like the crash was not too bad and the XM-6 still works....? If it is not broken and functional, try to mount it to a workbench in a way that it can't fly or move....take some security distance and start it, give it slight pushes with your gas stick...not too much, just to put some load on the ESC's.....do that for about a minute, switch off the XM-6, disconnect power and feel with your hands all ESC's....be careful, if one is faulty it can be very hot. If one ESC feels a lot different in temperature than the others, that will be the one to replace.

Interesting that the first crash happened after ca. 2:00 minutes and the second crash after 2:30 min.....


Chris

 

[Tahoe Ed]

I would check all the bullet connectors. Some of the DJI escs have had problems with the connection between the connector and the board. Many have removed the bullet connectors and soldered the motor wires directly to the esc.

 

[carlert]

Hello and thanks for your replys. I have just checkt motor by motor and esc to esc. I run each for about 1 minute and the esc was not warm. I also run the machine mounted on the table as it was when it crashed and run it for about 2-3 minutes but i didn´t hear anything od or felt any heat on the esc.

 

[atver]

A friend and I experienced this same problem with a CX-4 but using the WKM. Our problem was caused by a firmware bug that has since been corrected. Is your firmware up to date on your NAZA? If so, wondering if you may have a defective NAZA since your connections and ESC's were found good.

 

[carlert]

The first crash with DJI F550 was with NAZA and the latest firmware. The second crash Droidworx was with Wookong-M 5.20 firmware.

 

[atver]

This is odd with two different controllers. Double check your bullet connections being solid and not loose and your power distribution board for good solder joints.

 

[carlert]

Thanks for everybodys replys. I quick update. DJI is great with support. I have sent them my ESC´s and they will send me new ones when they got mine. The place where i baught them from (Flying-Hobby) is not so god on support for stuff like this. I ordered the ESC´s this Februari. I mailed them and first they told me to test the ESC´S and i have done that. Then they just wrote: "We are welcome if you want to buy any new parts." But on the other hand are they fast to ship and have good prices. i guess nobody can be good on everything.

 

[atver]

Thanks for everybodys replys. I quick update. DJI is great with support. I have sent them my ESC´s and they will send me new ones when they got mine. The place where i baught them from (Flying-Hobby) is not so god on support for stuff like this. I ordered the ESC´s this Februari. I mailed them and first they told me to test the ESC´S and i have done that. Then they just wrote: "We are welcome if you want to buy any new parts." But on the other hand are they fast to ship and have good prices. i guess nobody can be good on everything.

How did you verify your DJI ESC's were defective? Your test method would be helpful to me and others.

Thanks,
Jim

 

[PeterLester]

Here is what I did with my DJI ESCs with respect to the bullet connectors...... extended wiring from the ESC to separate bullets because the distance to the motors was too great.
Note their are connectors at both ends of the ESCs for fast connection and disconnection. Helps to speed up the motor balancing etc. and keeps the escs away from the prop wash for better lifting efficiency.

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I would check all the bullet connectors. Some of the DJI escs have had problems with the connection between the connector and the board. Many have removed the bullet connectors and soldered the motor wires directly to the esc.

 

[OneStopRC]

Too many connections to fail for my liking, remove any connectors inline and solder/splice the power wires then heat shrink the connection. Why add more points of failure and more weight to the aircraft.?

 

[VINHEX]

Interesting about distance from motors as well.. I've not herd that before NOT to say that there isn't but interested if is.. Do you have any reference to the max length they can be.. I'm using STD Dji ESC's on 6 x 60cm leads to Tigers and don't have any issues (Famous last words now!)

 

[PeterLester]

Agreed..... fewer connectors is best..... but there is only one additional connector per standard DJI 30A ESC.....i.e., the red one which enables simpler and faster individual motor balancing on the frame.
When motor balancing is completed, these red connectors will be tie-wrapped together to ensure they do not vibrate loose etc.
The other 3 per ESC are not extras but simply non-DJI bullets connectors that have been extended.
As far as additional weight.... insignificant for this S800 size Hex with much larger motors.

What concerns me is the lack of commercially available fit-for-purpose landing gear/gimbal systems for a Hero GoPro.....
The GoPro only weighs 73 grams while the landing gear/gimbal systems are in excess of 200 grams.

Too many connections to fail for my liking, remove any connectors inline and solder/splice the power wires then heat shrink the connection. Why add more points of failure and more weight to the aircraft.?