I can fly about 3:30 then the hex just powers down and falls from the sky. I've looked at the log (attached) and there appears to be a current spike but it doesn't make sense. Can anyone help? Broken 3 props so far trying to work this out.
Here are my specs:
ArduCopter 3.1
APM2.5
3dr current sensor
MediaTek GPS
3dr telemetry radio (433mhz)
RCT800 frame
2.4 6CH OrangeRx
30Amp Afro ESC SimonK
4220-650 MultiStar motors
11 x 5.5 carbon props
(2) 5000 mah 4s packs (40c 80c burst)
My bench tests show a maximum amp draw of 42 amps @ 640 watts.
Replies
Your very last Current reading showed a spike to 80 amps from around the 30 amps you had been typically operating at. Up to that point your Vcc (power to the APM) had been fine. Concurrent with the huge current draw you recorded a system voltage drop from 14.00 volts to 12.27 volts. To me this screams a serious short circuit that may have caused your APM to brown out.
The question is where? Obvious candidates are your ESCs or possibly a motor. It probably has nothing to do with your APM. Your APM is just a victim along for the ride!
Are you saying this has happened on multiple time about 3 1/2 minutes into a flight? If so something is heating up and shorting. I'd enable motor logging then I'd tie the thing to a workbench and run it at hover throttle or above to see if I could get it to fail in a controlled situation. A review of the motor logs might help narrow it down. Of course if it's on your workbench you just might see which motor fails first.
The logs do show a huge positive roll just as recording stops (rolls to the right) so I'd check for failures of the right motors or ESCs first.
How are you powering your APM ? The Afros only have a tiny 500 mA linear BEC.