Hey Guys,

Me again, I got my Quad all Set Up and had a pretty nice maiden flight, until one Motor stopped for around a second, so it dropped to the ground for I was flying just in around 1.50m height. Happend two times, both times same Motor, and all out of a sudden. Was flying countinously for around +5 min before the first time and then again for around 10min when it happend the second time. Checked directly the Temp. of the ESC (Blheli 30A) & Motor after the mini crash(es), and everything was even in temperature and definititely not hot ( ~30 - 35°C, if that matters).

Now I'm kind of clueless on how to find out where exactly the problem is so I dont have to risk crashing it directly again.
I'm not sure if just should re-solder all Bullet Connectors to get rid of the possible cause or if I can somehow check (specially) the ESC with my Multimeter? Or is there a chance that the ESC is not configured right? As it happend both times when I turned up the throttel, pitch "backward" & roll to the right or could that be a coincidence? The next thing is that this particular Motor had a piece of its cable isolation broken (shipped like that), directly at where it enters the heat shrink isolation that leads into the Motor. Checked the resistance between the cables as you showed me and everything looks fine. Nothing feels loose. Could it be that there are some broken wires where the Isolation is missing so that its getting a Problem when the current gets to high? (Total guess, correct me if I'm wrong).
Has somebody experienced something similar?
Tell me if you need more information.
Thank you for your help!  :)


First of all, if you are running stock ESC firmware (not "flashed ESCs" like BLHeli or SimonK) then you MUST set ALL ESCs battery type setting to either "none" or "Nicad".  Manufacturing tolerances of the Low Voltage Cutoff of the ESCs will cause one to cut off before the others.

If that is not the issue, you must find which motor/ESC is failing and fix it.  For me it was the pre-soldered bullet connectors on the motors had a bad solder joint.

If that is not the issue, it is possible that a bad battery voltage drops so low that again, one ESC resets before the others.

I recommend a Lipo alarm like this regardless of issue, but beware if flying GPS flight modes as they have magnets in them and can distort the compass.

Hi there,
Thanks for the answer.
I'm running flashed ESCs with BLHeli.
Also I got a Lipo checker that warns me at already 3.4V and the LiPo was fully charged. I luckily know wich one failed me. I will re-solder the Bullet Connectors and give you an Update!
Thanks for the Info.


Sooo... I resoldered the all there Bullet Connectors of the failing Motor, and the Problem is gone. Thanks for the help! Had a quality flying time today.