2nd crash need help with logs/diagnosis

Just joined and this is my first build so the learning curve is steep I appreciate any help or comments as I am out of ideas at this time.

Copter/Flight System
DJI 450
DJI E310 Propulsion system (motors, ESC, Props)
3S 5000 MAH Batt
Pixhawk flight controller -APM V3.4.3 Firmware
Tx X9D-plus with L9R Rx

First crash partially my fault original flight with 4S Batt to much power so changed to 3S to have better control and failed to update the the low battery setting. I heard the Pixhawk low battery alarm (constant beeping) but instead of doing RTL on low battery it flew away went up about 5’ titled about 30 deg. and crashed about 100’ from its launch position. I had a GPS lock before arming for flight and flight mode was Stabilize. Result was two damaged props.

So I repaired props reset mission planner for correct battery voltage and instead of RTL is set it to land on low battery. Copter in hover about 10’ flight mode was Stabilize. I heard low battery alarm again from Pixhawk after about 5 min. of heovering lost all control copter tilted and flew into the ground. Motors still trying to run!

  • Took the quad over and hooked to laptop it was in failsafe mode
  • Battery voltage was 11.81 - it took about 1400MAH to fully charge…
  • I am still learning so I am having trouble graphing
  • Radio is set up for no pulses on failsafe
  • I see IMU mismatch warning in the file but still researching
    -Inside when hooked up to laptop I get EKF occasionally but again still researching and not sure it’s relevant inside the house.
  • Outside with laptop hooked up I have GPS 3D fix and all seems normal

Update after more research and working with the log files I am understanding them better just to clarify a couple points the spikes you see in the log files are my poor landings!!! Still trying to understand the errors and what is causing the problem

Log Analysis and files below

Thanks again for any help.

Log File C:\Users\Owner\AppData\Local\Temp\tmp1E6B.tmp.log
Size (kb) 3167.474609375
No of lines 39257
Duration 0:15:58
Vehicletype ArduCopter
Firmware Version V3.4.2
Firmware Hash 6076bdfc
Hardware Type
Free Mem 0
Skipped Lines 0

Test: Autotune = NA -
Test: Brownout = GOOD -
Test: Compass = WARN - Moderate change in mag_field (25.69%)
Max mag field length (639.59) > recommended (550.00)

Test: Dupe Log Data = GOOD -
Test: Empty = GOOD -
Test: Event/Failsafe = FAIL - ERRs found: FS_THR FS_BATT CRASH
Test: GPS = GOOD -
Test: IMU Mismatch = WARN - Check vibration or accelerometer calibration. (Mismatch: 1.09, WARN: 0.75, FAIL: 1.50)
Test: Motor Balance = GOOD - Motor channel averages = [1567, 1543, 1531, 1493]
Average motor output = 1533
Difference between min and max motor averages = 74
Test: Parameters = GOOD -
Test: PM = NA -
Test: Pitch/Roll = NA -
Test: Thrust = NA -
Test: VCC = GOOD -

2017-01-01 14-53-39.bin (1.4 MB)
2017-01-01 14-53-39.log (3.1 MB)

No expert, but I see your battery failsafe is set to 11.1 v, which per the log is about when it triggered the battery failsafe. Are you using a power module? Log also show you only used 596mah of battery, but you said you charged almost 3 times that. Did you check power module settings and check the calibration of the power module?


Also check the battery size you have in settings.

Look here as well for additional information on power module setup:

I think the “21-1” is an EKF error, no idea about the “DIO-2”, someone else will have to look into these and their meaning



Thank you very much I looked and I was unable to find that to be able to graph it. I am using the power module and I calibrated the both the current and volts in mission planner using a DC amp clamp and my Fluke. I calibrated the amps at a 10 amp load. I have it setup in Mission Planner as monitor voltage & current, Other and Pixhawk.

I did have my Battery size set to the original 4S 4000 Mah so I will change that to 5000 Mah of the current 3S I am using thanks again I missed that. It may be the 3S batteries I am using have met their life expectancy and I have already ordered new 3S 7000MAH batts.

As I dig into the graphing more and understand it I see it sent the command to land which is what I had set up in MP but I would not call what it did a controlled landing in any way shape or from!!!

Thank you again I have now found were you graphed the volts it was under CURR.