Currents and Temperatures

Discussion in 'Cinestar 8' started by William Johnston, Oct 29, 2012.

  1. William Johnston

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    This is a continuation of the conversation started in "Crash cage or dome." I felt the topic should have it's own thread.

    So a brief recap. I got interested in monitoring the currents an temperatures because my Cinestar had all sorts of problems. The solder on the Deans plug melted. It would tip just as it was taking off. Position hold didn't work (it flew straight into a tree with position hold on). I didn't know what was going wrong. The bad flying behavior was caused by the ESCs getting too hot. I finally realized that it was pulling too much current. More than it was supposed to. I suspected something electrical which is why it took me so long to figure out that the problem was mechanical. The propellers were on upside. Oh well. :-}

    It's all working well now, but I am still interested monitoring the currents and temperatures and maybe this information will be useful to others.

    Lets start where I started. Here is a "before" flight with two Turnigy 5S batteries, 2 axis gimbal, and hero pro camera. It was probably around 90 degrees.

    Flight Time: 2012-08-03T00:05:04Z
    Flight Duration: 15 seconds
    Average Current (Amps):
    21.0 19.4 21.2 21.8 23.5 22.8 23.7 23.5 0.0 0.0 0.0 0.0 Total=177.0
    cw=89.5 ccw=87.5 (cw-ccw)/total*100=1.2
    Copter has a clockwise moment.
    Average Temperature (Celsius):
    68.4 64.2 65.2 66.4 75.2 76.9 79.9 71.7 0.0 0.0 0.0 0.0
    Maximum Temperature (Celsius):
    76.0 71.0 73.0 75.0 85.0 86.0 90.0 80.0 0.0 0.0 0.0 0.0

    Ouch! That's a lot of amps. By this time I had switched out my Deans plug for an EC6 plug which had no trouble with the 177 amps flowing through it. One other thing to note is that all the motors record a current of 25.4 amps and no higher. I think the GPX recording thresholds at the 25.4 amps so it's likely the real current was higher.

    Here is the same set up flown after I flipped the props over. Ambient temperature is in the 50s.

    Flight Time: 2012-10-28T18:54:33Z
    Flight Duration: 2 minutes 35 seconds
    Average Current (Amps):
    3.3 3.2 3.7 4.6 2.3 5.7 4.6 4.2 0.0 0.0 0.0 0.0 Total=31.6
    cw=13.9 ccw=17.7 (cw-ccw)/total*100=-12.0
    Copter has a counter clockwise moment.
    Average Temperature (Celsius):
    33.3 31.7 31.3 41.3 50.9 56.2 50.0 40.5 0.0 0.0 0.0 0.0
    Maximum Temperature (Celsius):
    39.0 39.0 43.0 56.0 69.0 69.0 62.0 50.0 0.0 0.0 0.0 0.0

    My ESC #5 is recording a current value that is lower than it ought to be. So the real current draw should be a little higher.

    It's a totally different world with the props on the right way. I'm lucky I didn't seriously damage the CS8. I could have burnt up all the motors and ESCs.

    So what are some correct currents that the CS8 should pull.

    An unloaded (no gimbal) C8 with one Quadropower 4S 6200mah battery:
    Flight Time: 2012-10-22T23:44:27Z
    Flight Duration: 3 minutes 35 seconds
    Average Current (Amps):
    4.5 2.6 4.2 1.5 1.5 1.5 3.6 2.6 0.0 0.0 0.0 0.0 Total=22.1
    cw=13.8 ccw=8.3 (cw-ccw)/total*100=25.1
    Copter has a clockwise moment.
    Average Temperature (Celsius):
    56.7 47.7 46.4 36.9 41.8 35.4 47.1 41.9 0.0 0.0 0.0 0.0
    Maximum Temperature (Celsius):
    67.0 55.0 55.0 41.0 46.0 41.0 55.0 51.0 0.0 0.0 0.0 0.0

    The CS8 with one with one Quadropower 4S 6200mah battery, two axis gimbal, and hero pro camera:
    Flight Time: 2012-10-28T18:33:56Z
    Flight Duration: 1 minutes 57 seconds
    Average Current (Amps):
    2.9 2.9 2.6 4.1 1.9 6.2 4.2 4.6 0.0 0.0 0.0 0.0 Total=29.4
    cw=11.6 ccw=17.8 (cw-ccw)/total*100=-21.0
    Copter has a counter clockwise moment.
    Average Temperature (Celsius):
    21.7 21.2 19.9 29.4 37.9 45.7 40.9 33.5 0.0 0.0 0.0 0.0
    Maximum Temperature (Celsius):
    26.0 24.0 23.0 34.0 41.0 54.0 50.0 41.0 0.0 0.0 0.0 0.0
     
  2. Gary Haynes

    Gary Haynes Administrator
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    Uh this will sound like a bit of a crazy question but did you check that the motor connections are correct, that odd number motors are spinning in one direction and even numbered motors are spinning in the opposite direction? That the proper props clockwise/counter clockwise are mounted to the correct motors and their direction?

    You didn't say what you are using for a flight control stack but if it is MikroKopter did you configure the stack correctly using MKTools?

    Transmitter setup correct and trim inputs set to neutral?

    I would suggest that you carefully re-check everything, perhaps find a local buddy who might be able to give some coaching. If everything is setup correctly then you shouldn't be seeing these types of issues. Any anomalies between the ship, flight control stack/software or flight transmitter could lead to your list of issues.
     
  3. William Johnston

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    Oh, thanks for all the tips, but there is nothing wrong with my C8 anymore. It flys quite nicely actually. I'm flying the default C8 with all MikroKopter parts.
     

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