Battery level instantly to 0, holy crap

[Zandian]

So, took my Mavic Air our for her maiden voyage and apparently forgot all the things you shouldn’t do with a drone, despite having a Phantom 4 and a Mavic Pro in the past. Flew her in 5 degree Fahrenheit weather, 18 MPH winds, oh and I forgot to put the two little feet down.

Actually she didn’t fly all that badly, for a ways out before video started failing-probably because the feet weren’t down. But the scariest thing was once I hit about 30% I started back. All of a sudden she read 0% battery and immediately started auto landing over a tree and I couldn’t stop it! Somehow, either by drifting in the wind, or maybe lower object sensing she landed a ways out in my front yard. Checked the battery readings and all three levels were halfway and green. Turned off the bird and back on and battery showed 30% again!

I have no idea what the hell happened but I would suggest others be very careful flying in extreme cold. Not something I want to experience again, that’s for sure.

It’s been too cold to try her out again to see if the battery issue was just a. Luke or whether I have a defect or something. Curious to see if others have the same issue.

Z

 

[amanakoinum]

I have no idea what the **** happened but I would suggest others be very careful flying in extreme cold. Not something I want to experience again, that’s for sure.

You gave the answer yourself: "Flew her in 5 degree Fahrenheit weather,..."

Very low temperature, batteries internal resistance goes up, voltage drops under load (delta_U = R * I, Ohm's law, high internal resistance = high delta_U), Software thinks battery is empty because voltage is low, Auto-Land starts.

There is a reason it says "operating temperature 0°C-40°C" in the technical specs. 32 Fahrenheit to 104 Fahrenheit.

 

[Zandian]

You gave the answer yourself: "Flew her in 5 degree Fahrenheit weather,..."

Very low temperature, internal resistance goes up, voltage drops under load (delta_U = R * I, Ohm's law, high internal resistance = high delta_U), Software thinks battery is empty, Auto-Land starts.

Yep I figured as much. Flown in cold temps with my Mavic Pro many times. Must have gotten lucky in the past. Wonder if there is any difference between that battery and this-or maybe the enclosure or for some reason because the battery is hanging from the bottoms instead of sitting on top?

 

[amanakoinum]

Yep I figured as much. Flown in cold temps with my Mavic Pro many times. Must have gotten lucky in the past. Wonder if there is any difference between that battery and this-or maybe the enclosure or for some reason because the battery is hanging from the bottoms instead of sitting on top?

Mavic Pro battery is much larger.
Probably takes more time to reach critically low temperatures during flight?
Maybe thinner plastic around the cells with the Mavic Air to save weight?

 

[4wd]

While DJI would point out the temperature was too low, during flight it would have generated more than enough heat to mean low temperature in the battery probably wasn't the cause.

If the battery does this again it might be faulty, need to test a couple of times in a safe area close by.
More likely it's the monitoring of remaining power which has glitched out for some reason.
Variations on this issue have been fairly common in previous models and firmware updates have improve things.

 

[Kilrah]

Leave the MA powered on the ground with that battery until it turns off by itself, then recharge fully to calibrate the battery's internal gauge. Then try to fly again at safe distance. If it does such a thing again the battery's defective.

 

[msinger]

But the scariest thing was once I hit about 30% I started back. All of a sudden she read 0% battery and immediately started auto landing over a tree and I couldn’t stop it!

Does your flight log show the battery instantly dropping like that too?

 

[thongbong]

It's the weather. I fly rc and lipos don't like the cold. I flew my air for first time yesterday. Same thing happened. Only flew for about 5 mins totally before I had to land.

 

[thongbong]

It was single digits for me too

 

[Zandian]

Does your flight log show the battery instantly dropping like that too?

I'll take a look at the log and see what it says. Didn't think to do that yet.

Z

 

[Zandian]

I figured I'd see lower battery life, just didn't think it would drop from 30% to 0% instantly. Funny that it landed from 2000ft or so when it was readying 0% the whole time.

Z