While on vacation recently, I flew the P3 three times over the ocean without any problems.  I had actually never had any trouble with it until I took it up on the 4th battery of the day (with lots of cool down in between).  On the final flight of the day I took it up about 20-25 ft and it started "going crazy".  It all but did a flip, turned wildly, dropped in altitude several feet, etc.  I freaked out and thought maybe someone got the case too wet when we were jumping off the side of the boats.  Who knows, really.

I took it up later to re-test it out at the hotel while the first set of batteries were charging.  When the problem re-surfaced 10 mins into the flight, my heart sunk.  I knew she was done for.

Then I came home and decided to do a little more in-depth investigation.  I found two flights in a row that had absolutely no problems (35k ft distance on them, using them until they were empty).  Then I tried a 3rd battery and she went absolutely nuts again, right away.  Pulled it out, tried the 4th battery and it was fine.

The DJI Go App shows nothing out of the ordinary on this particular battery.  All cells look normal, right?


I uploaded the logs to HealthyDrones, but again, everything looks "normal" on each of the screens.  Even the battery looks fine, which is what I suspect to the be the problem given it only happens when I put battery #3 into the drone.




Obviously, the easy answer here is to never use that battery ever again.  It's only been used a total of 6 times (3 of which had problems, but I didn't realize at the time I had been using the same battery).

Here is a video of what it looked like during flight.  It's the entire flight (only 20 seconds long).  As soon as I got it in the air, I hit record and let it continue until it touched down.

https://www.youtube.com/watch?v=J9fQYM1qM-I&feature=youtu.be

I just wanted to share in case anyone else notices their unit suddenly goes crazy, without explanation.  If you're lucky enough not to crash, try with a different battery.  I would say I dodged a bullet (not crashing the unit) 3 times in a row.

Looks good but strange behavior. Same battery both times? Did you watch the flight on the actual tablet to see if there were any strange stick movements recorded that may have been from an outside source of interference. I know it is practically impossible for something to be on the exact same frequency but not totally. Just a thought.

That is a very very weird video !!! check the battery contacts for any oil or anything that could make it touchy, if it was me i would put it on the battery screen and see the behavior of the phantom while its doing this, but wouldn't all this get recorded in the logs anyways if there was voltage fluctuations between the cells ?

Try do an IMU and then compass calibration with that battery and fly it with it and see if it happens again, just make sure if it falls the ground would be forgiving.

Let's have a look..


Oh, that doesn't look good.

Send that intelligent battery back, for an exchange or refund.

RedHotPoker

Looks like your bird wanted to do a little air dancing.  Yeah, definitely send that puppy back and get a new one!

RedHotPoker Posted at 2015-8-25 05:38
Let's have a look..

That looks like just after takeoff you suddenly had that first zombie body spasm ... your eyes aren't yellow by chance, are they?

Maybe the battery requires a FW upgrade?

Try keeping the FW file on your SD card in the P3, so the battery will update next time you use it.

pcmeid Posted at 2015-8-25 14:51
Maybe the battery requires a FW upgrade?

Try keeping the FW file on your SD card in the P3, so the ...

Same thought here

Yikes -  I wish there was a way to validate the FW of the battery just to see if that's the problem.  Obviously if I put the SD card in with the FW it'll auto-update.  So that's good.  But honestly, I might just be too afraid to take it up again.  I think I've had too many close calls with this battery.

sharper4 Posted at 2015-8-26 03:44
Yikes -  I wish there was a way to validate the FW of the battery just to see if that's the problem. ...

In your original post, you wrote something about flying 35k feet and that you "....flew them until they were empty."

Did you really fly a Phantom battery all the way down to empty - 0% battery left?

First thought is that at some point well above totally empty, you would have encountered either a low battery warning, a critical battery warning or both. You don't say anything about that. At any rate, I would seriously advise against consistently flying your batteries down to any level below the critical battery level.

I can't see how a battery malfunction would cause control issues like that.
Suggestions about battery firmware are even less likely to cause flight problems.
You could be missing the cause by concentrating on the battery.
More testing required.

I hope you are doing the gentle battery break-in.
Fly down only to 50% battery capacity, first ten flights.
Then, Take the battery down to 8% after twenty full charges.

This has been suggested from the top commander in cheif here.
Best to follow orders from the guys who run this circus tent. Forum staff.

RedHotPoker