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Is this battery toast?

Discussion in 'Inspire 1 Help' started by TheSaffer, May 31, 2016.

  1. TheSaffer

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    Hi, I know there are a few threads here regarding cell voltages, but I can't seem to find an answer.

    I have a brand new TB48 and I was told by DJI support to calibrate the battery by letting the Inspire idle with the battery until it turns off by itself. I turned it on and let it stand until I noticed that one cell's voltage is dropping way below the rest. I was told that the battery will shut down automatically and that the battery will not be damaged. It turned off at 3.2V on the one cell while the rest were at around 3.5V

    Is this too much of a difference in voltage at the end of the drain down?

    Is it safe to assume the battery is damaged and that I need to return it to the retailer?

    Any advice will be greatly appreciated.
     

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    #1 TheSaffer, May 31, 2016
    Last edited: May 31, 2016
  2. Dr. Ifly Drones

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    I can't tell you not to use it but, I can say I wouldn't trust it to fly my airframe. I was taught that anything over 0.2v difference was a dangerous situation.
     
    Daniel Abdallah likes this.
  3. The Editor

    The Editor Moderator
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    You should be fine.
    Packs will show a larger difference between cells as they discharge.
    Everytime you charge the pack a balance will be done. The cells most definitely should not be out of balance once charged but I wouldn't worry too much about just over 200mV when pretty much depleted.
    Just keep an eye on how the cells track together as you are flying. Should that particular cell show a significant imbalance during flight then I would retire the pack.
    I have one pack out of my twelve that sags a little on one cell when I am down to around 3.5v per cell. I am landing by then anyway and my flight times are not affected.
    Your difference is only 220mV between the lowest and highest cells and although 200mV is a good rule of thumb it is not a cast in stone type thing.
    Just be cautious, keep an eye on the pack and be mindful you may have a weak cell on that particular battery.
    If the difference starts creeping up higher I would probably keep the battery grounded.
     
    Dr. Ifly Drones likes this.
  4. TheSaffer

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    Thank you for the advice. I just couldn't get myself to trust that battery.

    Since I would rather be safe than sorry, I have now arranged a replacement as I don't want to loose my bird using a iffy battery.

    Just a side note. Maplin will replace a faulty battery up until one year after purchase.