So I went into sport mode and flew a straight line for about 300 ft at about 150 ft up.  Not a windy day and temp was around 40F.  As I came to a stop I saw a warning message pop up in the upper left hand corner that said "Battery Overcurent During Discharge".  Is this normal?  Is this a battery defect possibly?

On another battery I was in Sport Mode flying around like crazy... hard turns, full throttle for about 2 mins straight and didn't get any warning with that.

Anyone else have that issue?

Probably a dip in voltage while flying in sports. I wouldn't worry about it too much. I haven't seen that yet but batteries sagging does happen from time to time. When dealing with it on a adc, you'll usually set a few checks (like 7 or 8) over a short time , and if the voltage is low over those 7 or 8 checks, that means the battery needs charging and sound an alarm. I assume you were low already when you did the 300 ft in sports. I really wouldn't worry unless it happens while full charge. That's indication one of the cells is out of balance with the others, it acts like a vampire.

There's 3 cells inside in series. If one of them is lower in voltage than the other two, it starts charging itself. So the other two batteries are stressed into supplying both the ac and the battery that's out of balance. That's why you always want to put lipo of the same capacity and charged the same voltage in series. Maybe one cell is a bit off the other two. I would discharge it to 10% and charge back full 3 times. Called refreshing, and it helps bring back capacity in older cells.

It happened around the 10 minute remaining mark so my battery was at 50%.

I guess I'll keep an eye on it and if it happens again I'll see if I can isolate it to the battery.  Thanks for the input.

Yeah np. I added a little on the end of the last post, might help.

I actually went into the settings within the DJI GO App and now I have the battery voltage on the main screen so I can monitor it during flight.

Daley Posted at 2017-1-21 07:16
I actually went into the settings within the DJI GO App and now I have the battery voltage on the main screen so I can monitor it during flight.

You still won't see it.  You've got to upload to Healthy Drones to see it since it happens in a millisecond.  I was getting this warning, as well.  Then after calibrating everything, it just went away.  I've down the transitional climb out like you mentioned to reproduce the issue, but it doesn't do it now.

I calibrated the IMU & gimbal at a CNC machine shop with a PERFECTLY leveled granite surface.  Then compass, VPS (DJI Assistant 2) later.

It was scary as heck getting that & it stays on the screen for a moment.  

Daley Posted at 2017-1-20 08:40
It happened around the 10 minute remaining mark so my battery was at 50%.

I guess I'll keep an eye on it and if it happens again I'll see if I can isolate it to the battery.  Thanks for the input.

When this happened in my case I was at 374 feet, sport-mode and still had 74% power...loss of H-power but then regained after a bit.