I am helping a friend of mine diagnose a problem with his quad.
Flight controller: APM 2.6
Battery: 3S 25C 4000mAh
Battery failsafe: disabled
It was working pretty well - he had been flying it in Stabilise, Loiter and RTL. However, sometimes it would inexplicably drop from the sky like a rock.
We inspected it for visible hardware faults (broken wires, poor connections, etc) but could not see anything obviously wrong.
I have been having a look over the dataflash logs to see if I can identify what the problem is, but I am not getting very far. I was wondering if there was anyone out there would could help.
Out of the sixteen logs I was able to download, three are flagged as having brownout events. I assume these are the ones that were generated during the crashes. I will attach these four for your reference.
(Note that the crashes occurred several years ago, hence the strange datestamps on the files).
Of the brownout files, I have been paying particular attention to ‘2014-11-09 15-13-19.log’ as it seems to be a good example of the problem. This is the log I will discuss below.
When I graph CURR.vcc, I’m seeing fluctuations of only about 0.044v, which seems ok to me.
When I graph CURR.volt, it looks like the battery voltage never drops below 10.47v, which seems reasonable, too.
Does anyone have any idea what the problem might be, or what areas I should be looking into?