Major Battery Voltage Deviation
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kyrvas
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United States
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My P3P Battery #1 has a major voltage deviation in Cell #1 (0.102v). During today's flight at 35º F, the AC AutoLanded.
Since the AC was still close to the Home Point, I could see the status lights were flashing red.

AirData.com gave me the two attached battery records.
Question: Is this a correctable problem, or, is the battery done for future flights?


Battery #1 100% Life.png     Battery #1 Major Cell Deviation 0.102v.png
Battery #1 100% Life.png
2019-3-8
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Bashy
Captain
Flight distance : 2354357 ft
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United Kingdom
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Run the battery right down, until the drone itself turns off, then charge it up and see what it says then.
2019-3-9
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kyrvas
lvl.3
United States
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Bashy Posted at 3-9 20:24
Run the battery right down, until the drone itself turns off, then charge it up and see what it says then.

Hi Bashy - how do I run the battery down? When in the AC it AutoLands then shuts the motors off?
2019-3-9
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Mark The Droner
First Officer
Flight distance : 2917 ft
United States
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Not a good idea to launch with a partially charged battery.  Be happy it didn't drop from the sky.  :-)  

2019-3-10
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Bashy
Captain
Flight distance : 2354357 ft
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kyrvas Posted at 3-9 20:38
Hi Bashy - how do I run the battery down? When in the AC it AutoLands then shuts the motors off?

just start the motors using the sticks (dont take off) and go make a drink, write some emails, watch telly......
2019-3-10
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kyrvas
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Mark The Droner Posted at 3-10 02:49
Not a good idea to launch with a partially charged battery.  Be happy it didn't drop from the sky.  :-)

Thanks Mark the Droner - I now understand that's not a good practice; and, it did drop quickly to the snow, the landing gear brushing the snow but I was able to throttle it up and land it on a dry deck.
2019-3-10
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kyrvas
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United States
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Bashy Posted at 3-10 20:13
just start the motors using the sticks (dont take off) and go make a drink, write some emails, watch telly......

Okay Bashy . . .
2019-3-10
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Mark The Droner
First Officer
Flight distance : 2917 ft
United States
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I'll just add some more stuff...

Personally I doubt anything is wrong with the battery.  

Know that if you want to do a deep discharge, the correct procedure is to first start with a fully charged battery.  

Since you would then have a full charge, you might as well check the cell balance, and I bet it is fine.  

If I was gonna deep discharge it, I'd use a device such as this:  https://www.ebay.com/itm/DJI-Pha ... g:c4IAAOSwKIpWAS3W.  In fact, I have one that looks a lot like that and use it sometimes for my P2 batteries.  I've never needed or wanted to use it for the P3 batteries.  

If I was gonna use the Phantom to deep discharge with the motors running, I would put the props on so that the prop wash can keep the system cool via the vents in the top shell.  I'd probably do it outside on the grass.

MHO

Good luck
2019-3-11
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kyrvas
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Mark The Droner Posted at 3-11 02:15
I'll just add some more stuff...

Personally I doubt anything is wrong with the battery.  

Mark the Droner - very good advice; thank you.

After a full charge today, the cell balance was perfect.

Battery #1 All good.png
2019-3-11
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Mark The Droner
First Officer
Flight distance : 2917 ft
United States
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Nice.  Note that Cell 1 is 49 mv (.049 v) off from cell 4.  Nothing to keep you up nights, but it wouldn't hurt to do a test flight at low altitude next time just for good luck.  Then check your log to see how the battery behaved.  

Good luck
2019-3-12
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kyrvas
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Mark The Droner Posted at 3-12 03:47
Nice.  Note that Cell 1 is 49 mv (.049 v) off from cell 4.  Nothing to keep you up nights, but it wouldn't hurt to do a test flight at low altitude next time just for good luck.  Then check your log to see how the battery behaved.  

Good luck

Thanks Mark - I will do just that.
P.S. Before flight the cells were identical! I just tried to Upload the proof image but the Upload window would not activate the file to continue; it would list the file butg not activate the selection of it? Anyway, after charging Battery #1 to 100%, DJI GO showed each battery cell was identical at 4.25v.




2019-3-12
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BriannaDiaz
New

India
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Flight 1 & 3 perfectly fine. Flight 2 has a few deviations but your battery started at 21c, should have been a little warmer if possible(especially in cold temps) and it was not charged to 100% (started at 97%)

I'm going to say it's probably fine, charge it up fully, warm it up to 25c or so and see if it happens again. But you are probably good


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2019-3-18
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kyrvas
lvl.3
United States
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BriannaDiaz Posted at 3-18 04:14
Flight 1 & 3 perfectly fine. Flight 2 has a few deviations but your battery started at 21c, should have been a little warmer if possible(especially in cold temps) and it was not charged to 100% (started at 97%)

I'm going to say it's probably fine, charge it up fully, warm it up to 25c or so and see if it happens again. But you are probably good

Brianna - my apologies for not responding sooner; have not been on the DJI site for a month.
Thanks for the battery temperature advice; I knew it was a cold day but when the GO App read Save to Fly, and the status lights were green, I lifted off.
2019-4-17
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