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Advanced [Solved] Major battery voltage deviation - Opinions pls :-)

Discussion in 'Phantom 3 Help' started by Elysion, Mar 8, 2016.

  1. Elysion

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    Hey guys, I asked this in the DJI forum but wanted some extra opinions, if that's okay :)

    I was checking out my flight logs and noticed major deviations in the voltage of my battery.

    Since the bird is pretty new (less than a month) and the battery has only been charged 3 times, I wanted to be extra cautios and ask for opinions.

    Drone is clean, no crashes, no battery warnings until now, always had the voltages (top right in the app) in sight and flew carefully, no sudden speed-ups.

    The only thing I noticed was that sometimes I had sudden drops in voltages from 3.8/3.9 to the high 3.5V areas (seen on top right corner of the app, changing color from green to yellow), thats when I throttled and prepared to fly back.

    HealthyDrones.com - Innovative flight data analysis that matters
    HealthyDrones.com - Innovative flight data analysis that matters
    HealthyDrones.com - Innovative flight data analysis that matters

    Please note that with my second battery, I did not have any major deviations until now, both were handled pretty similarly and charged with the same stock charger until full.

    "Healthy Battery" #1

    "Healthy Battery" #2


    Any help is greatly appreciated, thank you in advance for your support :)

    Best regards from Germany-
    Elysion[​IMG]

    Edit: Ambient temperature was around 0° Celsius / 32° F.
     
  2. KyleMaxxUAV

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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


    Sent from my iPhone using PhantomPilots mobile app
     
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  3. msinger

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    "Major deviation is when a cell differs more than 0.07v from the other cells" is a definition made up by the creator of Healthy Drones. Just because your battery reported one "major deviation", it does not necessarily mean there is any reason for concern. Per some research I've done, others feel deviations less than 0.1V should be ignored. If you upload your logs here instead, you'll be able to see all of the recorded deviations.
     
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  4. KyleMaxxUAV

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    Also, it appears you just went straight up to 1600ft ? Going full throttle straight up on a cold battery, that wasn't fully charged, in 0c temps is probably not the best idea. ??


    Sent from my iPhone using PhantomPilots mobile app
     
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  5. Elysion

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    Thanks so much for the fast replies. [​IMG]

    Yeah you're right P3P, will fully charge and test again with a warmer battery.

    Thank you for the link msinger, will upload my logs to there as well from now on.

    Kind regards-
    Elysion
     
  6. Elysion

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    Well, I wanted to see the maximum altitude, but I never went up full throttle, always easy on the stick, also always had the voltages under control!
     
  7. KyleMaxxUAV

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    Looks fine to me, I had a faulty battery, it was always out of balance(even sitting on the ground) had 10+ major deviations every flight, did a deep discharge cycle to 10% and then full charge . It also started to get a bit swollen.
    It was an actual bad battery !!

    Contacted DJI, sent photos, disposed of battery, new one is good to go


    Sent from my iPhone using PhantomPilots mobile app
     
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  8. Elysion

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    Will upload my files to phantomhelp and take a look there, but from what I can tell now, the deviations seem to be within safe range, I will calibrate them as well now and keep an eye on the voltages with a higher temperature (at least 25°C.)

    Thanks again for the help, marked as solved [​IMG]
     
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  9. Elysion

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    [UPDATE]

    Did a complete discharge until the drone went off, while doing so, I noticed big deviations of cell 1, while e.g. Cell 3 was @ 3.2V, Cell 1 was at 3.0V.

    I gave it a 30 minute rest at cool temperatures, now charging it to 100%

    Also uploaded files to phantomhelp:
    Phantom 3 Log Viewer - PhantomHelp.com

    @2m 24.6s and @6m 17.5s you can see deviations of over 0.1V of the reported battery, any opinions?

    Thanks-
    Elysion
     
  10. Elysion

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    [UPDATE #2]

    DJI honored my warranty without even asking for logs! They just told me to send it to them and that I'd get a replacement unit within 10 days!

    Better safe than sorry, I am willing to wait the few weeks to have a reliable bird in the air, you can never be sure enough ;-)

    Thanks again!
    Elysion
     
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  11. Baldo81

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  12. Elysion

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    I discharged the batteries until the aircraft turned off by itself, the internal deep discharge protection prevents it from going below 3.0v, which is absolut minimum.
    I then let them cool down to about 20° C. and let them rest for about 30-35 minutes, before I recharged them again.

    After I did that, my deviations were gone.

    The only important notice I want to give you on this is that you never should discharge the batteries too fast, that is what they are really sensible to, I flew my drones to about 25% and then just let them sit still outside my balcony (I wanted a nice airflow to cool down the drone) until they turned off, then do the procedure as stated above.
    Some people do not recommend it, as it can lead to battery swelling or even a complete malfunction of the battery, I actually think that not every phantom flyer is not an engineer and just wants to fly that thing until it comes down on its own, that's why the integrated safety features :)


    In general, I really think that it also depends on various circumstances, such as air temeprature, battery temperature, flight behavior and also firmware version (the last one had some additional safety features for cold environments, dunno if that applies to you).

    When did the voltage drops occure? Did you suddenly push the stick down to accelerate or just gently push it? Or did you do sudden movements in general?
    Also you are down to 27 cycles as you stated, so you might give my method a try if you feel safe in doing it, it helped me:

    HealthyDrones.com - Innovative flight data analysis that matters

    http://www.phantomhelp.com/LogViewe...HYQC3W9X7XGWTI5LL-DJIFlightRecord_2016-03-12_[17-35-52].txt

    Hope it helped a little! And always remember, keep a cool head and the drone in the air! ;)

    Elysion
     
    #12 Elysion, Mar 13, 2016
    Last edited: Mar 13, 2016
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  13. Baldo81

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    Thanks for your help!
    I completely agree with you. Both we're using the same method to bring her below 8%
    I usually flight gently as as are 5 years that I'm used to fly quads with no-intelligent batteries :)
    I did another discharge cycle and seems better, but I'll see the logs later today as soon as I can upload them.

    The deviations I got aren't that big but I prefer to flight safely and trust my batteries
     
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  14. Elysion

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    That's good to hear, keep me updated!
    And completely agree with the safety, better safe than sorry :)

    Cheers
     
  15. Baldo81

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    DJI told me that they'll replace the battery, and I need to contact my dealer that will assist me... let's see if the dealer will help :)
     
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  16. Elysion

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    That's great news! I decided to send my batteries in as well, just to make sure everything is working flawlessly, that's what the warranty is for ;)

    Have a safe flight-
    Elysion