Params File.param (16.6 KB)
Using T Motor Flame 60A ESC
T Motor MN4116 450KV Motors
Pixhawk PX4 FCU
Hexcopter configuration on Ardupilot
ESCs pass calibration we think
Motors not calibrating
We measured current draw at constant throttle input and each motor is pulling a different current
Could be a wiring issue?
Please help
Without props? On the bench? That test produces meaningless results. Please do not test a closed system in a open-loop configuration. It will never work like you expect it to do.
Without props on an assembled drone as the documentation says to.
Current draw test was just to troubleshoot, not our main method of calibration.
We keep failing the motor calibration test, suggestions on how to proceed?
Where does the documentation say to measure the current and see if it is different from motor to motor?
Hello Bryce,
You can perform this ground/bench test by defining the motor as RCIN3 option in the Servo Output section of Mission Planner or the Motor Test section. Performing this test in Stabilize mode or any other flight mode can be misleading because the autopilot will attempt to level the aircraft, which will likely result in different motor commands—as you have likely experienced.
By comparing each motor’s current with respect to RPM against the motor’s datasheet, you can obtain reliable results. This is the method I use for my bench tests. Since I don’t have a thrust stand, I ensure that the propeller matches the specifications in the motor’s datasheet to achieve the expected current at a given RPM.
This approach has worked for most of my tests. Whenever I encounter issues with a motor, ESC configuration, or wiring, I use this method to identify faulty motors or ESCs.
It doesn’t, as I mentioned that was just a troubleshooting method.
We are trying to calibrate the motors and are following the documentation to do that.
By performing ESC calibration with no props, we pass ESC calibration but cannot calibrate the motors.
What do we do next?
We defined it as RCIN 3 like you mentioned and are doing it in stabilize mode as well.
Should we be testing each motor individually and comparing RPM to current draw on the spec sheet?
How do you suggest we do the motor calibration in ardupilot ?
I’m not sure if comparing an unloaded motor’s current is the right approach. In my case, it was misleading. However, once I installed the propeller recommended in the datasheet, the comparison became more meaningful.
What I mentioned earlier assumes that you have already completed the calibration step and want to verify that each motor generates a similar thrust by comparing RPM and current. If calibration is already done and you just want to check motor performance, you can proceed with this method.
That said, you should note each motor’s maximum current to avoid burning it. Also, I recommend testing motors one by one, I personally prefer checking each motor independently.
We have already validated the motors with a thrust stand.
What we’re trying to do now is arm the drone and fly. We are able to arm just fine, we can calibrate the ESCs as well
However when we increase the throttle the motors do not spin evenly and create small jerking movements in the drone body. (No props)
Is it fine to attempt to fly like this and see if it corrects during flight?
Test all motors using mission planner’s “motor test”:
After that, add props and fly.
Assuming of course you have read and used https://github.com/ArduPilot/MethodicConfigurator/blob/master/images/ArduPilot_Methodic_Configurator.pdf?raw=true first 
Okay thank you,
Direction and order are all good, is the uneven RPMs not a problem at this stage?
They run all together just fine and respond to throttle up and down inputs as well.
Like I said in the first reply the test is invalid. The results are invalid and that is not a problem.
That is also explained here
Don’t. With Flame ESC’s set these:
MOT_PWM_MIN,1100
MOT_PWM_MAX,1940
Okay I have followed the instructions and changed the required values, I have this message: MOT_SPIN_MIN too high 0.50 > 0.3
In the motor test section, I had to set MOTSPINARM to 0.47, this was the minimum value for them all to spin
Thank God we have that warning message!
0.47 is very, very wrong.
They all need to turn at 0.20 max.
0.47 is wayyy off.
There is a big mess-up somewhere. reboot the FC and the ESCs and try again.
Is the battery fully charged?
Battery is fully charged yes, we are using a Herewin 6S 22000mAh 22.2V 488WH 25C battery
If the problem persists update to the latest ArduCopter firmware and reset all parameters from default and start over.
We fixed it, we had to turn on the hardware switch before plugging the main battery back in. (We have seperate batteries for motors and FCU) during the ESC calibration.
We were turning the hardware switch on too late which meant we never had the ESCs calibrated correctly I think.
Thanks for the help, we got the drone in the air too.