Edge Power Modules

Voltage across GND and V_bat is 1245mV constant
Voltage across GND and I_bat is 5mV constant

Okay, that’s valuable.

Could you please take your Edge out of the frame and connect only Wi-Fi module and PM with a battery of a known voltage to it and repeat the measurements in QGC?

I’m also interested in resistance value of ADC_IN0 and ADC_IN1 wires inside a connector.

Could you also ssh into your Edge (using Putty or whatsoever) that has a fixed IP address of 192.168.0.1 and execute:

watch -n0 cat /sys/kernel/rcio/adc/ch2 and then the same with ch3 and describe what’s the perceived variance? Is it ~5 or ~50 units?

I’ve spent the week confirming that somehow it is now working relatively normal. I can’t explain what has changed. I took it all out of the frame and tested as requested and got the same values, so I put it back in and that seems to have fixed it which is puzzling. So perhaps a loose connection, but that would explain no readings not wildly inaccurate readings. I’m happy to leave the original issue until it pops up again and address what I am now experiencing.

I can confirm that voltage readings are definitely taking place when connected to both the power module and non-power module battery connectors, but current sensing is ONLY the main power module battery connector.

Something that is now confusing is that the current readings are displaying incorrectly but appear to be measured correctly as the FC is triggering battery failsafe at the appropriate moment:

  • Current Failsafe set to 15% of the capacity of a single battery (4500mAh 6S) as only one is being monitored and system Voltage Failsafe at 21.0V
  • Current Failsafe triggered on a flight where the HUD was showing 21.50V under load when coming in to land and 2572mA consumed (43% of 4500mA remaining, 28% until Current Failsafe Threshold with voltage not dipping anywhere near the Voltage Threshold). In real time I immediately interpreted the live data as a premature failsafe trigger.
  • The two batteries in question charged up an average of 3870mAh (14% battery remaining) which suggest it landed immediately when it should have
  • Flight time of 11 minutes consuming the amount the batteries charged (3870mA*2) gives an absolute system current draw of 42A where the HUD was showing 15-17A (single battery channel out of 2, so displayed system current draw of 30-34A) which is rectified by the logs below.

So where’s the issue? I don’t put it down to chance that it simply triggered at seemingly the perfect moment for the failsafe and as a result the Current Multiplier needs to be adjusted - it triggered at the exact time it should have from assessing the battery charge. It appears as though it is reading the current one way and interpreting it through the FC for the failsafe values and displaying another set of values on the HUD.

Below are screenshots of the log viewer through Mission Planner as there isn’t an option to assess your logs in QGC. All the values line up with what the HUD was showing. Is there a way of explicitly determining if it was Low Voltage OR Current Threshold that triggered the battery failsafe? I would assume it must be the current as those values don’t appear to line up with reality. For some reason uploading the log isn’t working, I’ll try it as a separate post.

FYI*** Was testing every mode, the radio failsafe and a long hover (for current draw analysis) on this set of flights, hence it is a very busy log.



The log doesn’t seem to want to upload. Upload % gets to 100% and it just doesn’t attach.

Thanks for the report. I’ll try to answer appropriately after some analysis. At the meantime could you please upload the logs somewhere else? Like Dropbox, Googledrive, Mega or whatever.

As a side note - I have experienced a LOT of issues trying to download logs off the FC. The PreArm: Logging Failed message frequently pops up when I’m attempting to download the logs and the downloads TimeOut at random percentages. Solutions over at Arducopter suggest later revisions than 3.2.4 (Edge custom version) may resolve the issue. I don’t have telemetry dropouts in the field or anything like that so it appears to be an issue isolated to log file transfer.

@george.staroselskiy

Can you provide any feedback on the battery reporting values?

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