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Battery over current during discharge, attempted fly away! SOLVED!!
1712 23 2015-10-29
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plumbob11
lvl.1

United States
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Hello, this is my first post but I am a long time reader. I have been flying collective pitch hell's for 10 plus years and i am very familiar with lipo batteries and their care.
I have 59 flights on my Phantom 3 Advanced. Yesterday I noticed that the battery life on one of my packs had dropped to 88% in the app. This pack said it had 26 charges. So i decided it was time for a deep discharge to properly cycle the pack. I flew the phantom down to 20% and brought her down. I decided to hand catch which i almost never do. But thank god that i did! While holding the leg i dropped the throttle to turn off the esc's. When I did the props all went to 100%! The app had a red warning that said "battery over current" nothing I could do with one hand on the remote would stop the props. So i carefully put my remote on the ground and pressed the button on the pack to turn it off. After the battery cooled down and with the props removed I reinserted the pack to check it out. The voltage was at 12% and all cells were within .1v of each other. In the history log it says "battery over current during discharge". i proceeded to leave the power on till it dropped to 8% and recharged it up to 50% for storage. i am now a bit confused as now the total flights went from 26 to 12 and the battery life from 88% to 100% again.

So, here iare my questions. What the heck happened? Is an over current event a failure of the battery or of the ESC's?

And also... Would you trust this battery pack any longer? Do I RMA the pack or the whole setup phantom and all?


2015-10-29
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DJI-Tim
DJI team

Hong Kong
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Hi, plumbob11!  What was the temperature that day? Battery could behave that strange because of low temperature environment
2015-10-30
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plumbob11
lvl.1

United States
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DJI-Tim Posted at 2015-10-30 01:14
Hi, plumbob11!  What was the temperature that day? Battery could behave that strange because of low  ...

I am i sunny California, it was 78 degrees that day.
2015-10-30
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plumbob11
lvl.1

United States
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So, I have completely solved this problem. I finally got the time to fully investigate and read the flight log,  here is the chain of events.

- I brought the phantom down to a hover at 20% battery
- i continued the hover to discharge the battery to 18% (about 40 seconds)
- I grabbed the leg and hand caught the phantom.
- simultaneously the Battery dropped from 18% all the way to 15%
- Return to home initiated at the moment I grabbed the phantom! (so it was trying to climb to 150ft to return to the spot i took off from 30 feet away!!!!) NOT A FLY AWAY!
- AT this same point the "over current during discharge" occurred probably because i was holding the leg and the phantom could not climb the esc's went to 100% to try and prevent a crash?

So there is a good lesson here... sometimes its easier to assume the Phantom has a mind of its own and is malfunctioning when it is actually trying very hard to do what it was programmed to do!
2015-10-30
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nfatoys
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United States
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plumbob11 Posted at 2015-10-31 03:28
So, I have completely solved this problem. I finally got the time to fully investigate and read the  ...

The logic of your conclusion makes sense.   However, if the Phantom was already Home (I assume you were at the Home position when you caught it), I can't see why the Phantom would attempt a RTH maneuver?   I believe the Phantom 2 assumes it's Home when it's within a 20 foot radius of Home.
2015-10-30
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IMI193
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plumbob11 Posted at 2015-10-30 15:28
So, I have completely solved this problem. I finally got the time to fully investigate and read the  ...

I was about to suggest you inadvertently went full power somehow while holding it, which caused the over current, makes perfect sense.
2015-10-30
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plumbob11
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United States
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IMI193 Posted at 2015-10-30 13:22
I was about to suggest you inadvertently went full power somehow while holding it, which caused th ...

No i am 100% positive I have the throttle down all the way, I wanted to do a CSC but couldn't with one hand.

I am not guessing what happened, it is all noted in the flight log. The RTH is noted that it engaged at 15% battery in the flight log, I would have had to manually cancel it and then power down. (which you can't do with one hand lol!

2015-10-30
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plumbob11
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United States
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plumbob11 Posted at 2015-10-30 13:56
No i am 100% positive I have the throttle down all the way, I wanted to do a CSC but couldn't with ...

The only weird part, is that the battery instantly went from 18% to 15%. But i guess that is not strange for a battery that needs to be deep discharged and "reset". Right?
2015-10-30
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plumbob11
lvl.1

United States
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So elevation is wrong, i am holding it at this point.
2015-10-30
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plumbob11
lvl.1

United States
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the battery over current doesn't show up in the app's playback but here is what it shows on the battery.
2015-10-30
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DJI-Dave
Captain

United States
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plumbob11 Posted at 2015-10-30 13:58
The only weird part, is that the battery instantly went from 18% to 15%. But i guess that is not s ...

Right that can happen.
2015-10-30
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DJI-Dave
Captain

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nfatoys@hotmail Posted at 2015-10-30 13:06
The logic of your conclusion makes sense.   However, if the Phantom was already Home (I assume you  ...

No it does not assume it is home within 20 feet.
2015-10-30
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DJI-Dave
Captain

United States
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plumbob11 Posted at 2015-10-30 12:28
So, I have completely solved this problem. I finally got the time to fully investigate and read the  ...

Very true. I have seen this for years, and many, many posts about so called fly aways.
2015-10-30
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Geebax
Captain
Australia
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DJI-Dave Posted at 2015-10-31 08:23
Very true. I have seen this for years, and many, many posts about so called fly aways.

Nice to know it does exactly what it says on the box....

We mere humans should learn not to interfere with the machinations of a properly functioning autonomous machine
2015-10-30
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IMI193
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United States
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plumbob11 Posted at 2015-10-30 16:56
No i am 100% positive I have the throttle down all the way, I wanted to do a CSC but couldn't with ...

Posts like this reinforce to new owners like my self how quickly and unexpectedly things can go bad, thanks.
2015-10-30
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DJI-Dave
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Geebax Posted at 2015-10-30 14:33
Nice to know it does exactly what it says on the box....

We mere humans should learn not to interf ...

Yeah, the worst thing you can do is panic. And that happens to new and experienced pilots.
2015-10-30
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DJI-Dave
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United States
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Geebax Posted at 2015-10-30 14:33
Nice to know it does exactly what it says on the box....

We mere humans should learn not to interf ...

Yeah, the worst thing you can do is panic. And that happens to new and experienced pilots.
2015-10-30
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DJI-Dave
Captain

United States
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Geebax Posted at 2015-10-30 14:33
Nice to know it does exactly what it says on the box....

We mere humans should learn not to interf ...

Yeah and the worst thing you can do is panic. But don't feel bad I have seen new and experienced pilots do this.
2015-10-30
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DJI-Dave
Captain

United States
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Geebax Posted at 2015-10-30 14:33
Nice to know it does exactly what it says on the box....

We mere humans should learn not to interf ...

Yeah and the worst thing you can do is panic. But don't feel bad I have seen new and experienced pilots do this.
2015-10-30
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DJI-Dave
Captain

United States
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Yeah and the worst thing you can do is panic. But don't feel bad I have seen new and experienced pilots do this.
2015-10-30
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nfatoys
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United States
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DJI-Dave Posted at 2015-10-31 05:22
No it does not assume it is home within 20 feet.

So, are you saying that if I start up my Phantom, lift off the ground and hover a few feet above the take off Home point, then shut off the Remote Controller, the Phantom will climb to about 60 feet, then perform a soft landing?  I've never tried this.  I thought it would behave the same as how "HL" mode works on the Phantom 2.    Within about 20 feet, Home Lock mode doesn't work as expected.
2015-10-30
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jayredone10
Second Officer
United States
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nfatoys@hotmail Posted at 2015-10-30 21:47
So, are you saying that if I start up my Phantom, lift off the ground and hover a few feet above th ...

I have caught my friends Phantom 2 Vision about 3 feet off the ground and shut the battery down before. His controller went into panic red LED flashing mode because of a bad AA battery. The Phantom 2 was on the ground but the motors were idling.  It went into go home mode and started its slow climb up. There are a lot of trees in the area we fly. It was easy  to catch vs replacing the shell again from anthor tree attack.
2015-10-31
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DJI-Dave
Captain

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nfatoys@hotmail Posted at 2015-10-30 18:47
So, are you saying that if I start up my Phantom, lift off the ground and hover a few feet above th ...

Actually they might have changed it. I will have to test it. I know for sure it used to... I know of a guy, on one of the forums, that did that with his P2. He was under the eave of his house and shut off the remote thinking the P2 would just land. It did not, it went up and hit the eave and crashed before he had time to turn the remote back on and cancel RTH.

2015-10-31
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DJI-Dave
Captain

United States
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Sorry for the multiple posts in this thread. Some times the forums software does not let you post and then when you try again it will at a later time post all of your attempts to post.
2015-10-31
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