Motor does not change speed under throttle, wire keeps coming off


#1

Weird one here. So I have another quad I’ve been building. All good except that prop 2 was going round the wrong way. Used BlHeli to reverse the direction. Tested the motors both in Betaflight and BLHeli and motor 2 goes faster and slower when moving the slider up and down.

First test flight (I say test - hovering on the living room floor) and all goes well briefly when suddenly motor two judders and bit and then stops. One of the wires has come off. Aha I think dry solder, so I re do it.
Every time I solder the wire back on, it comes off. I do this two times and the wire and solder just won’t stick.
Aha - glue gun (solves all wiring problems :wink: ) Tried that and the glue melted along with solder. WTF
Multi-meter time; nope no shorts between the wires.

Ok, time to cut the cable, clean the pad (again) on the FC and use different solder.
So far so good, increase the throttle and it doesn’t come off. Only issue now is that the motor doesn’t spin any faster and judders if you move the quad around. (Props off at this point and I’m hand holding it)

I’m wondering if the ESC for motor 2 doesn’t like being reversed. These motors (Mr Copper 2306) are reversible so I’m wondering if there is some other problem.

Tomorrow I’ll try swapping the wires round to see if that fixes the problem, then reverse the motor in BLHeli back to normal direction.

Any other thoughts or ideas on other areas to look gratefully received.


#2

Ok

so you hot glued and soldered down the motor wire for motor 2 and it still came off…
Hot glue I beleave melts at 60C.
Now I’ve glued down motor wires before and never had the glue melt.

At a guess

  1. You have lifted the motor pad (that why solder wont hold) and cause you have a weak connection. The current flow is higher than it should be over a much smaller trace causing heat to build and melt your hot glue.

  2. Or you have a damaged ESC

  3. A judding motor can be a ESC setting incorrect. Check and compare with the others.

You could switch the motor to another ESC and see if the problem stays with the ESC or moves with the motor.

You can reserve motor direction on any motor either by swapping the two wires around or BLHeli.
But I don’t think thats your problem.

Happy Hunting :slight_smile:


#3

Found the problem - one of the ESC’s on the board looks like it’s gone kaput. So asked Alex and team at unmannedtech if they have a replacement ESC board for the Emax F4 Magnum v2. Not overly impressed given it’s only had one flight and no crashes.

Update: Muppet error; (thanks to Cameron at unmanned tech for pointing out my school boy error) - don’t put motors that can draw 50A on a board rated for only 30A and then fly like crazy.


#4

Happy to hear you got it sorted… or at least found the cause of the issue. Are you gonna swap out your motors or try get a higher rates 4in1 ESC? If you need suggestions just let us know :slight_smile:


#5

Thanks Alex, and yes please for some suggestions. Already replied back to Cameron asking that very question :slight_smile:
Currently I’m thinking of swapping out the FC board and sticking it on the ‘cursed’ GT M-5, then putting the Kakute F7 AIO in this build and buying separate ESC’s that are up to the job.

p.s. I’m thinking Wraith32 Metal V2 - 60A :smiley:


#6

Yeah those ESC are just about the biggest ones (in terms of current rating) we sell and work great :-). Which motors/props are you using so I can see if there are any cheaper suggestions?


#7

These :slight_smile:

https://www.unmannedtechshop.co.uk/mr-copper-2306-2700kv-brushless-motor/

Consider four Wraith 32 Metal v2 now ordered :smiley:


#8

Yeah those ESC will work well :-). Let us know if you have any other issues. Should be a sweet setup assuming you have a high c rating battery :slight_smile:


#9

100C 4S battery is what I typically run, so I’m hoping it will be sweet :slight_smile:


#10

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