DJI Drone Help Forum

Almost!!! Lost N Found


#1

Hi All,

Had my 1st close shave with my Mavic Air today. Would be grateful if someone experienced could shed some light on a why I suddenly received a “Critically Low Voltage Warning Land as soon as possible, or battery will be damaged.” alarm.

Batt % dropped from 61% straight to 0%

Flight log below:
https://www.phantomhelp.com/logviewer/T5WRPY4COGQGOOO39DDV/

Weather was clear / sunny, a little wind, and temp about 7 deg C.

Thanks in advance,
Jim


#2

At a quick glance. This appears to be some sort of FC calculation error. Your battery looked fine. See what @BudWalker has to say when he has time…


#3

Thanks,
I don’t know much about drones yet, but the cell voltages looked a bit erratic. Then actually increases after the critical batt alarm.
Drone is brand new direct from DJI (bought November, opened Christmas day), all firmware was updated in Go4 App. Batteries have max 5-6 charge cycles.

Only thing i didn’t do with this batt was fully charge it immediately before flying. It was last charged fully on 2nd Jan, and I’d had the drone turned on to play with Go4 App settings, hence the 81% charge at take off.


#4

They will look that way when you give full throttle and elevator. Current goes up, battery goes down.


#5

That makes sense, will wait on budwalker getting back to me then…
Thank you


#6

Sorry, but I don’t have much to add here. Looks to me like the smart battery system made the determination that the battery had no capacity left. But, no indication why. The eventLog stream in the tablet .DAT may have some pertinent info. Look here to see how to retrieve that .DAT file. The file name will end with “FLY049.DAT”


#7

Thanks,
Just tried to upload my FLY049.DAT file, but new forum members aren’t allowed to upload… :grimacing:

FYI, I fully charged the same battery this morning and did a test flight at home (didn’t leave the garden). I got almost 17min flight time, albeit mainly hovering.

https://www.phantomhelp.com/logviewer/PIN2MBVOKTGSL1FF6Q46/

What do you use to analyse DJI DAT Files?? I’ve had a look at AIRDATA, but are there free versions available?

Thanks,
Jim


#8

You could upload to Dropbox or similar and then provide a link to the uploaded …FLY049.DAT.

I like to use CsvView or DatCon to analyze .DAT files. They are free and can be obtained here and here.


#9

Thanks BudWalker…

Link to the original failed flight txt file: https://www.dropbox.com/s/v2rounko1lcqa1b/DJIFlightRecord_2019-01-08_[13-22-03].txt?dl=0
Link to the original failed flight DAT file: https://www.dropbox.com/s/ktw6rb1ofvpuk08/2019-01-08_13-21-40_FLY049.DAT?dl=0

I have since fully charged the same battery and completed a test flight from 100% to 13% Batt without issue (albeit most was spent hovering and didn’t venture too far). I’ve linked these too, just to help.

Link to the post charging flight txt file: https://www.dropbox.com/s/emjhfjgtlwr1t93/DJIFlightRecord_2019-01-09_[11-49-00].txt?dl=0
Link to the post charging flight DAT file: https://www.dropbox.com/s/qhwskz2fmwiu93u/2019-01-09_11-47-50_FLY054.DAT?dl=0

Thanks for your help…


#10

I looked in the eventLog stream and couldn’t see anymore than what we already know.


#11

Ok, much appreciated…
I sent DJI an email earlier today so will wait to see what they say.
Was no issues today after charging, but doesn’t fill you with confidence that it won’t happen again…


#12

Looked here as well. Just for your own informational purposes here is the event log, for reference.

2019-01-08_13-21-40_FLY049.log.txt (42.1 KB)


#13

Ok,
Thanks, will check that out