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Battery Deviations Question w/Log

Discussion in 'Pro/Adv Discussion' started by NCTideFan, Feb 27, 2016.

  1. NCTideFan

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    Hello everyone.. I would appreciate some feedback on some battery deviations I am seeing in my flight logs.. I have seen 1-4 from time to time in some recent flight logs. However, this morning I noticed multiple major deviations (the most yet); and I would like to know if I should be concerned about this. All deviations to-date have all been on cell #1. Today there were just many more than usual.

    The temperature this morning was around 56 degrees F (13 or so C?), I do not use radical control movements, and the deviations continued pretty much throughout the entire flight. The battery has been charged about 20 or so times based on best practices I've seen published on DJI.

    I received no alerts on the controller during the flight. The battery voltage did appear in yellow toward the end of the flight (I show voltage on the screen at all times).. No alerts though so I assumed this is normal as the battery charge nears the 30% threshold.

    Folks, any information would be appreciated. I only have this one battery and would hate to think it's defective so soon; but I'd like to know before going up again. If defective is the case here, what's DJI's approach to this? Do they tend to replace defective batteries or is it pretty much 'you're on your own' - Thanks all.

    Flight log is shared here: HealthyDrones.com - Innovative flight data analysis that matters
     
  2. flpholt

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    opps 502 feet wouldn't post that
     
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  3. clarky150

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    My battery is same on cell 1 was like this straight out the box,got a replacement on lts way


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  4. Mark The Droner

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    Have you done your deep discharge yet?
     
  5. KyleMaxxUAV

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    What did you do ? Send faulty one to DJI and they replaced it ?


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  6. Oso

    Oso

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    Healthy Drones is useful to an extent, but it is known for frequently showing cell 1 in the red. The author picked a number to use as the trigger for a major deviation. As he was working on it, he would even take advice from members here on changes to the settings for different things. He is the one who assigned when a cell shows red or not.

    Healthy Drones does provide interesting data and I use it myself to possibly highlight something to watch for, but I personally assign much more weight to what DJI tells me either through the app or other documentation. If the app tells me the cells are green, I trust it more than Health Drones. Same as when the app shows me if cells are yellow, etc.

    Since you said the battery now reached 20 cycles, if it were me I would go ahead with the recommended deep discharge and then watch that battery.

    All that being said, it's you not me who needs to be comfortable with that battery. Use our feedback as data points for making a comfortable decision. Good luck!
     
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  7. NCTideFan

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    I thought of that after..I generally run it to around 10-15% every time I go up, but nonetheless I did continue to run the motors this am once I brought it down ..I took it down to 9% before turning it off.. I will charge it tonight and take it up tomorrow and post results..thanks!
     
  8. KyleMaxxUAV

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    What would a better # be for a major deviation ? Just for my own knowledge?


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  9. Oso

    Oso

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    Hi sir. I'm afraid that I am not enough of an expert to make a definitive call on that. I can say that I have read numerous times that a .1v deviation is more of a cause for alarm than the .07v used in Healthy Drones. A battery is clearly vital, so I again emphasize that I am not an expert on this one so please seek confirmation before assuming I am correct.
     
  10. KyleMaxxUAV

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    I was just wondering your thoughts, I won't take them as facts. I guess if the number was even 0.09v it would have hidden the majority of those deviations.
    I have a battery that seems to be doing something similar. My worst deviation was 0.113v. It has me concerned but with only 5 cycles on it I'm flying it hard until 20 cycles, doing the deep discharge and if it doesn't change it will be going back to DJI, along with my crashed drone if the battery fails for replacement.


    [​IMG]


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  11. Oso

    Oso

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    Okay that's fair. Just thoughts as if it were my own battery.

    I would watch the GO app. Is it showing me green for each cell and reasonably balanced (.1v or less deviation) across cells? If so, my thoughts are exactly the same as yours. It would have me concerned, but with only one instance I would watch that it doesn't get worse and do the deep discharge at 20. If that didn't change anything, it goes back.
     
  12. KyleMaxxUAV

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    Yes, when charged it looks well balanced! But when flying, if I go full throttle it sometimes shows yellow in the top right (lowest cell voltage) and even red once before I backed off.
    To me I'd rather drive it hard and have it fail and need to be replaced than baby it / waste my warranty only to have it fail once out of warranty. Just my point of view.


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  13. NCTideFan

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    Thanks for all the help guys, this is great information I appreciate it. For my part, I charged the battery fully tonight in preparation for tomorrow. All cells read the same, except for cell number one which is .05 below the rest right off the bat. I will post results from tomorrow's flight and hopefully the deviations will be corrected by the deep discharge today.
     
  14. KyleMaxxUAV

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    Unfortunately I'm guessing that batt is gone.... Is it still under warranty ??


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  15. NCTideFan

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    The battery is, yes.. 23 charges owned for about 3 weeks now.
     
  16. KyleMaxxUAV

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    Try the deep discharge, if it doesn't come out flawless send it back. These type of batteries aren't going to get better and more reliable with time, only worse. I would prefer to start with problems and run into small issues later, rather than medium sized issues now and huge problems later. And we all know it will show up right after the warranty ends.


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  17. NCTideFan

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    Yup... flew a test flight (low altitude over land) for about 20 minutes this morning.. only 3 major deviations this time, again all on cell #1.. but the largest being one of 0.135v, a new high. I've opened a ticket w/DJI and will post the results for those who are interested. Thanks again for all the help!
     
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  18. Oso

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    I'm curious. I know it was mentioned several times in the thread but I don't see that you noted if you had already done the suggested deep discharge at 20 cycles. Have you already done that and it didn't help with the deviations?
     
  19. NCTideFan

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    I did do this, after the initial flight yesterday morning.. I landed, removed the rotors, and started it back up and ran it down to 9%. At that point, once I stopped manipulating the controls, it assumed it was on the ground and shut off the craft automatically.
     
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  20. Oso

    Oso

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    Gotcha. Sounds like you made the right call then if you still have a .135v deviation. I'm glad it worked out well and you discovered this without a fatal battery failure during flight. Cheers!
     
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