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Phantom 2 battery problem

Discussion in 'General Discussion' started by nammac, Sep 10, 2014.

  1. nammac

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    I have two batteries which were purchased 5.5 months ago. One has been discharged 24 times while the other has been discharged 31 times. I did a firmware update this afternoon to see if that would help my short flight times. I am only getting 5 to 7 minutes where as I use to get 17-18 minutes before getting the red lights. One battery surprised me last week while over water, had to quickly fly back to land since the copter was trying to land itself. The other battery seemed ok then. Now today both batteries are giving me short flights-- 5 minutes on one and 7 minutes on the other. I checked the last battery immediately after the flight and the % charge was 49% and the battery life is at 92%.
    Cell 1 3805 MV
    cell 2 3821 MV
    cell 3 3746 MV
    I completely discharged one battery earlier and recharged it and then did a test hover. In 7 minutes my voltage dropped to 10.9/10.8 so it landed. I hope these batteries, for what I paid for them, are good for much more than 5/6 months.
    Any ideas anyone.
     
  2. ProfessorStein

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    How are you storing them between flights? And how long do they have to wait between flights?
     
  3. nammac

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    They are always in my home. They probably went 2.5 weeks between the last flight when the flight time was normal for me. I do keep them charged, rotating one then the other.
     
  4. nammac

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    Now on the last two occasions I used them they were in a hot car, during a wedding, before I used them after the ceremony. I don't know if the heat inside the car would damage them or not? That is the only difference they have experienced which is out of the "normal" I can think of.
     
  5. ProfessorStein

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    The Phantom batteries are LiPo's, so when you're storing them for longer than a week between flights, you should store them at 40%-50% capacity. You definitely begin to degrade the batteries if you store them at full charge (or fully spent, for that matter). YOUR depletion seems a little extreme... but not knowing the full history, it's hard to say.

    And, yes, unfortunately... heat is the enemy of ANY battery. They should ALWAYS be stored in a cool, dry environment. Keeping them in a hot car is a big no-no.
     
  6. Wedeliver

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    There is a lot of discussion about how to charge and keep your batteries and I saw just a couple things that I thought might need further discussion. I have been told a lot of stuff about LIPO's and that you should discharge them all the way before re-charging, then I was told the worst thing you can do to a LIPO is discharge them all the way.

    Also, I would not recommend to keep them on a charger all the time.

    I do not think there are any "tricks" that can bring a LIPO back to life.

    Humm, I wish there was an idea on how to help with this issue. I did read recently here that DJI might have changed the warranty on the battery to maybe 6 months or 1 year. I might have been having a dream, but I would look into that if I were you.

    Good luck and let us know how it works out. Especially if you figure out some way to bring those batteries back to life since they aren't that old to begin with.
     
  7. N017RW

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    Aside from all the debate about use, care, and restoration...

    It looks like one or both of cell(s) 3 are bad as determined by the voltage differential when compared to 1 and 2.

    They should be within a few mV of each other. I can't say what is the acceptable range for difference is but that looks significant.
     
  8. ProfessorStein

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    I'm not sure there's any disagreement that discharging a LiPo fully will shorten it's life. ;)
    That seems to be what everyone can agree on.

    DJI does recommend that you occassionally discharge your Phantom batteries to below 10% (8% seems to be the gold standard). But that is simply to recalibrate the battery so it's intelligence circuit continues to accurately determine how much charge is left. And, unfortunately, it's likely that the process will shorten the life. Not by much. And if you only do it once a month, every two months, every 20-30 charges... whatever... you're not going to notice it.

    I don't believe that DJI has officially changed their battery warranty... but it would seem, from other posts here in the forums, that they do tend to be quite lenient in it's application, and have replaced batteries that were 1 year old or more.
     
  9. HarryT

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    I'm afraid that this really does sound like a case of user error. Keeping your batteries fully charged is a REALLY bad idea, and will damage the cell chemistry. No warranty is going to cover abuse of this kind.
     
  10. ProfessorStein

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    You can certainly try. Worst they can do is say no... and you're no worse off then you were :)
     
  11. nammac

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    Just contacted B&H and was told the batteries have a one year DJI warranty. I keep the batteries stored in my home and they have only been in a hot car for maybe a couple of hours 2 or 3 times this summer. They are not kept on a charger but are charged after each flight. The longest period between flights was recently and was about 2.5 weeks. So I should not recharge the batteries until prior to using them? This kinda puts a kink into doing a quick unplanned flight when you have to wait 1 + hours for a charge.
    I just find it strange that both batteries are having the same issue at the same time although one seemed to go a extra flight before the extreme voltage drop problem. Then again maybe not since both are the same age and have been treated the same.
    I could be wrong but I don't think this was a gradual regression in flight time but more of a all of a sudden thing.
    I have contacted DJI by email to see what they think.
     
  12. ProfessorStein

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    Yep... that's what all of us face. This isn't unique to Phantoms or multi-rotors. It's everything that runs on LiPo's... including laptops.
    Store them at 50% capacity. It's better for the battery than a full charge or no charge, anyway... and then you're always ready for at least a 10 minute flight or so if you need something immediate. And if you know you'll need more, it should take much less than an hour to "top it off".

    I have seen only a brief exposure to heat really kill a LiPo. So even a couple hours in your car, depending on how hot the day was, could have done the job. But... you'll usually also see some puffing/swelling of the battery, as well, due to heat exposure. So it's hard to say if that was the cause.

    By the way... keeping your batteries in a hot car can also cause them to explode. So... all-in-all... probably not a great idea.


    I think that's the key. Even if storage isn't at the root of your issue, they're likely behaving the same because they've had the same kind of hard life. ;)

    That does make this case a little odd, I have to admit. Typically degradation is very gradual. But... it is possible it's a perception thing. It was sooooo gradual that you didn't notice anything until all of a sudden you realized you were only getting 5 minutes of flight time. But, with the type of swing you describe, that sounds unlikely.

    Silly question... you didn't mention how you're actually doing your testing... have you double-checked all your test equipment? Probably not an issue since you know you're also getting reduced flight times proving that it's a battery issue rather than a problem in the testing itself, but something to check.
     
  13. RobertMfromLI

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    Some places don't recommend storing fully charged LiPo batteries for even a week, much less 2.5 weeks.

    That said, I have, numerous times. And, unlike you, I've made the mistake of leaving it in a hot car for far longer (had a week stint in the hospital for an antibiotic reaction).

    Now, here's the thing. I apparently get a LOT longer (includes video proof) than normal flight times. 19-20 minutes before my iOSD mini installation. 17-18 minutes after it.

    INOTHERWORDS, I think there's something wrong with your battery.

    Regardless, I'd stick with the 50% rule. If you recharge the batteries a bit earlier than you're flying that's fine. But, the problem is if you're doing that every day, in the "just in case I fly" scenarios... the charge and discharge cycles will take a toll pretty quickly.
     
  14. HarryT

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    What I do personally is charge my batteries to 2 solid + 1 flashing state level after flying. From that state it takes only 20 minutes or so to top them up to a full charge before I go out flying.
     
  15. RobertMfromLI

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    /\--- +1
    Great plan! Far better than mine... here's another suggestion to add to Harry's. Get a car inverter. They are really cheap (especially on Amazon). Charge while you drive to your location - his 20 minutes is probably within most travel times to flying spots.

    I picked up one really cheap, and use it to charge "Battery 1" while we are flying on battery 2. It won't fully charge it during the flight, but we also usually do regular ground photography as well,so we take a little ground photo break and come back in 40 minutes to "Battery 1" fully charged and ready.

    Even so, during a flight, we've managed to recharge a battery that was "drained" (new firmware limit of 20%) to a high enough level for another 4 or 5 minutes of flight time.
     
  16. ProfessorStein

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  17. RobertMfromLI

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    Gee, thanks... I am already deep into next week's paycheck!!! :lol: :lol: :lol:

    No, seriously, thanks. :)
     
  18. nammac

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    B&H told me today the batteries have a 1 yr warranty with DJI. Am I to understand that you only charge the battery prior to use? So if a event happens suddenly which requires the Phantom you have to wait 1 + hours for the charge to be completed.
    I don't keep mine on the charger but am guilt of charging after use. Also, I keep my batteries in my home except on a few occasions when they were stored in the "hot" car for maybe a couple of hours until I was able to fly. The longest period between flights was maybe 2.5 weeks (once) which was prior to the current problems. Up until this I was flying usually at least once a week sometimes more.
     
  19. RobertMfromLI

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    I charge usually after use...

    The *proper* way to do it is to charge to 50%, let it sit until before use, and then charge it the rest of the way. 2.5 weeks is too long. One week is, per many, too long, to leave an LiPo battery fully charged.

    From a battery manufacturer for things like our copters:

    • Any storage near a week, or longer, is supposed to be with the battery at 40-60%
    • Best temperature is 37-40 degrees F (not an easy task - see next bullet for a better idea - this range requires bags to prevent condensation/moisture and other issues)
    • Best *NORMAL* temperature is 77 degrees F or less

    But again, I do it the same way as you half the time. The other half, I leave it at 20% and charge it before use.

    Doing it the "proper way" would mean 30-40 minutes charge time (since you are at 50%).

    In short...
    • Fly
    • Charge to 50%, leave out of copter (always safest thing to do, just in case of battery failure - only damages battery)
    • Forty minutes before flight, charge to 100%
    • (repeat) Fly
    • Charge to 50%...

    Considering the prices of the batteries, I'm thinking of doing it that way... I really should be... but am not.
     
  20. RobertMfromLI

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    BTW, on the off chance, they ask you how you've taken care of/used your batteries, I'd suggest the "In short..." method above be your answer... ;)