4 in one, more like 3 in 1

Long story short, I made the poor decision of buying an ESC from Ali express and it backfired. I bought a 4 in 1 30 amp esc and paired them with some Aokfly motors (they are actually really nice, I recommend them). But 1 of the 3 escs only kinda works but it makes a really raspy sound (as if there is gravel in the motor) when you add power, plus it takes way more throttle input to make it spin at the same rate as the other escs. The motor also only jitters until about 20% throttle and then finally starts to actually rotate, but the other 3 escs work perfectly fine.

I'm thinking it's some kind of timing error but I don't really know where to look. Any tips would be helpful.




Elite member
A bad connector, bad solder joint on the motor wires or a faulty mosfet inthe ESC would could cause that.
Yeah I switched around the motors, i'm sure it's ESC 1 that is the problem.

I doubt I messed up the soldering connection that bad that many times, unless you are referring to the pre-done solders.

By bad connector are you referring to the signal wire for the esc making poor connection?

Is there a way to detect/fix a bad mosfet?

Thanks for the tips though really appreciate it.


Elite member
The bad solder joint could be on a bullet connector if you used one, on the soldering of the motor wire to ESC or on one of the mosfets to the ESC.

I don’t think a signal wire would cause your problem.

Checking mosfets that are soldered is tricky. One thing you can try is to measure the resistance between each otor phase wire and the battery positive wire on the faulty motor position and compare with one of the god positions. All 6 readings should be the same. Repeat the 6 measurements using the batery negative wire instead of the positive. Again all 6 teadings should be the same, but they might be different to the other 6. The motors should be disconnected when you do the test. With one group of 6 readings, you might see a moving result due to capacitors. That's OK, but you don't have a fixed result to write down. What you're loking for is each reading to behave the same as the others. From each group of 6 results, any anamolous ones indicate a problem.


Site Moderator
Staff member
Yeah I switched around the motors, i'm sure it's ESC 1 that is the problem.
You could try fixing as @d8veh suggested. The only other choice is returning it. That’s the down side to the 4 in 1 concept, when one goes bad you scrap 3 good ones.
For the most part the resistance readings are identical, I'm not sure how large the discrepancies are supposed to be but it looks to be in working order. I'm convinced it's a configuration thing, maybe in BL heli suit somewhere? Is it possible to run one esc off of a different protocol than the others? Might give good old pwm a shot just to be sure.

I'm using a naze 32 and it won't let me use anything above one shot unfortunately, Even though my ESCs are dshot compatible.
Yeah I did it with the motors tab and after using BL heli suit since I thought that would fix the problem.
I might just give up and order a new 4 in 1, since i have not learned from my mistakes.


Eternal Student
You could just buy a single one to use with the 3-in-one. Not as pretty, but functional.

Edit: Did you try just running PWM? What version of Betaflight are you running?
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