ESC or motor issue, please help understand

Dear Community,

I had a F450 frame with pixhawk 2.4.8, 30A simonk esc, 2212 920kv Motor. So I was flying with that drone using 2S battery. Everything was good.

Than I changed the batter to 3S, after ESC calibration the drone does not flying. After another thread community helped me understand that it is most probably ESC issue, i should use blheli.
But I cannot understand how that drone was flying with 2S.
May be the reason of not flying with 3S is not ESC, but motors. Is RCOUT graph enough to understand that?

Can someone please give some advice.

I am also attaching2019-12-01 10-12-27.bin (247.3 KB) 3S.bin (187.8 KB) the logs for 2S and 3S flights:

Thank you for you time.

I don’t know what you are using for batteries but both the 2S and 3S have serious voltage sag trying to fly that craft.



Describe the components on the craft and it’s all up weight with the 3S battery.

Thanks much for your answer.
This is my drone set:

2212 920kv Motor

  • Type : 22 x 12mm
  • KV: 920rpm/V
  • Voltage: DC 7-12V
  • Weight: 53g

30A SimonK firmware Brushless ESC.
Cont. current: 30A
Max. current: 35A
Input Voltage: 2-4S lipo / 4-12 cell Ni-MH/Ni-Cd
BEC: 5V 2A (Linear mode)
Size: 55x26x8mm (length 145mm including power cable)
Weight: ~24g

F450 frame Spec:
Width: 450mm
Height: 55mm
Weight: 280g (w/out electronics)
Motor Mount Bolt Holes: 16/19mm
G.Weight: 395g
Wheelbase: 17.7in/450mm
Net weight: 272g

Pixhawk 2.4.8 32bit ARM Flight Controller

1045 Propeller

Per my calculations, my drone should be able to lift 2kg, with 3S.
but may be I did something wrong…

I gifted one of this to someone I know (it was the price I suppose). I wouldn’t go for anything less than a 3S battery for this one. Btw the stock motors and the ESCs (as well as the props) are pretty much garbage. The person I gave this to told me that his drone was smoking after like 10 seconds of hovering. Everything worked fine after he swapped the motors and ESCs with decent ones.

You are way off base with the all-up-weight for flight on this craft. With 3S power you would not want to be more than ~1.1kg. It’s simple, you want to hover at 50% throttle. That’s it.

dear Dave,
I am sorry, but I do not understand your explanation.
May be I do not have enough drone knowledge, sorry((

Thanks much!
Do you know whether your friend treid bheli ESC with this frame?
and may be I also need to change motors, hmm, which one you recommend?


Nope, not BlHeli ESCs, believe they are SimonK ESCs:

Motor-prop combo here:

Thanks much!
You know what is strange, when I compare the parameters, they are exactly the same as the ones that I am using:

Yes @Aeroakram it’s absolutely right

Ready to sky motors are good ~40%

You can use sunnysky ohh yeah it’s really enjoyeble motor , emax 2213 it’s good motor , T-motor air gear version it’s awesome dude you pickup any motors it’s giving batter result from ready to sky also some chinese motor

Happy flying :slightly_smiling_face:

A properly designed multirotor should have ~2:1 thrust/weight ratio meaning it will hover at 50% throttle. “being able to lift 2kg” is not what you want. You want “being able to hover at 50% throttle”. That all-up-weight (total weight including battery) is ~1.1kg. What is this crafts All-up-weight?