Battery voltage measurement issue

Hi - I have a problem where my octocopter running a cube orange initiates an RTL after 5 - 15 minutes of flight. I’ve reviewed the logs and voltages seem to be where they should be. I’ve tried multiple power bricks. I do note that Mission Planner exhibits odd behaviour when I set it up. If I set the first power module to Other -> Other -> 8:Cube Orange Mission Planner reverts to Other -> Other -> Blank. It also seems erroneously report the amount of battery remaining (whether it gets this from the Cube Orange I’m not sure) as 19%.

When the fault occurs there is an uncommanded small increase in revs and then a further auto commanded increase as the copter tried to perform an RTL (it can’t it’s tethered down).

If I disable the RTL on battery low function the Cube Orange beeps and the voltage remains stable. The low voltage is set at 20.16 volts and the issue appears around the 22 volt - 24 volt mark.

Often the error Test: NaNs = FAIL - Found NaN in CTUN.TAlt appears. I’m not sure if it related. There is also a motor balance fail error message but this is very intermittant. It may be because the copter is tied down perhaps?

  1. Here is the output from the auto analysis:

  2. Log File C:\Users\dm\Documents\Mission Planner\logs\OCTOROTOR\1\lastlog.log

  3. Size (kb) 23378.24609375

  4. No of lines 280036

  5. Duration 0:12:40
    Vehicletype ArduCopter
    Firmware Version V4.0.2
    Firmware Hash aae944a8
    Hardware Type
    Free Mem 0
    Skipped Lines 0
    Test: Autotune = UNKNOWN - No ATUN log data
    Test: Brownout = GOOD -
    Test: Compass = GOOD - mag_field interference within limits (1.69%)
    Max mag field length (600.13) > recommended (550.00)

Test: Dupe Log Data = GOOD -
Test: Empty = FAIL - Empty log? Throttle never above 20%
Test: Event/Failsafe = FAIL - ERRs found: FLT_MODE FS_BATT
Test: GPS = FAIL - Min satellites: 0, Max HDop: 99.99
Test: IMU Mismatch = GOOD - (Mismatch: 0.16, WARN: 0.75, FAIL: 1.50)
Test: Motor Balance = FAIL - Motor channel averages = [1235, 1307, 1215, 1272, 1332, 1372, 1347, 1174]
Average motor output = 1281
Difference between min and max motor averages = 198
Test: NaNs = FAIL - Found NaN in CTUN.TAlt
Found NaN in CTUN.DSAlt

Test: OpticalFlow = FAIL - FAIL: no optical flow data

Test: Parameters = FAIL - ‘MAG_ENABLE’ not found
Test: PM = GOOD -
Test: Pitch/Roll = GOOD -
Test: Thrust = GOOD -
Test: VCC = UNKNOWN - No CURR log data

I’ve attached the log file also.

Any suggestions would be very much appreciated!

2020-02-17 11-07-02.tlog (329.8 KB)

This is the last log from the Cube Orange :slight_smile: Maybe this might help shed some light. :slight_smile:

You’ll need to upload the dataflash log from the Cube. It’s the .bin file.