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Battery over current with attempted fly away!

Discussion in 'Pro/Adv Discussion' started by perchybits, Oct 30, 2015.

  1. perchybits

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    Hello, this is my first post but I am a long time reader. I have been flying collective pitch hell's for 10 plus years and i am very familiar with lipo batteries and their care.
    I have 59 flights on my Phantom 3 Advanced. Yesterday I noticed that the battery life on one of my packs had dropped to 88% in the app. This pack said it had 26 charges. So i decided it was time for a deep discharge to properly cycle the pack. I flew the phantom down to 20% and brought her down. I decided to hand catch which i almost never do. But thank god that i did! While holding the leg i dropped the throttle to turn off the esc's. When I did the props all went to 100%! The app had a red warning that said "battery over current" nothing I could do with one hand would stop the props. So i carefully put my remote on the ground and pressed the button on the pack to turn it off. After the battery cooled down and with the props removed I reinserted the pack to check it out. The voltage was at 12% and all cells were within .1v of each other. In the history log it says "battery over current during discharge". i proceeded to leave the power on till it dropped to 8% and recharged it up to 50% for storage. i am now a bit confused as now the total flights went from 26 to 12 and the battery life from 88% to 100% again.

    So, here is my questions. What the heck happened to make this happen? Is an over current event a failure of the battery or of the ESC's?

    And also... Would you trust this battery pack any longer? Do I RMA the pack or the whole setup phantom and all?
     
  2. robinb

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    Do you have another battery you can try ?
     
  3. perchybits

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    Yes i flew it today with a different battery to test it out and everything seems fine?
     
  4. robinb

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    I wonder if you could use the original battery but with the drone tethered in some way to see what happens.
     
  5. perchybits

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    So, I have solved this problem. I finally got the time to fully investigate and read the flight log, here is the chain of events.

    - I brought the phantom down to a hover at 20% battery
    - i continued the hover to discharge the battery to 18% (about 40 seconds)
    - I grabbed the leg and hand caught the phantom.
    - simultaneously the Battery dropped from 18% all the way to 15%
    - Return to home initiated at the moment I grabbed the phantom! (so it was trying to climb to 150ft to return to the spot i took off from 30 feet away!!!!) NOT A FLY AWAY!
    - AT this same point the "over current during discharge" occurred probably because i was holding the leg and the phantom could not climb the esc's went to 100% to try and prevent a crash?

    So there is a good lesson here... sometimes its easier to assume the Phantom has a mind of its own and is malfunctioning when it is actually trying very hard to do what it was programmed to do!
     
  6. Corvette595

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    My wife thinks mine has a mind of it's own. She has said that it sounded like it is "Mad" several times.

    I need to start another thread about why it gets "Mad" and won't take off if I leave it on the ground connected for very long farting with the settings. I have to turn it back off and then on and it will fly.
     
  7. Corvette595

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    Now that would be a funny video! A Phantom 3 tied to one of those things that you screw into the ground to tie your dog up with.
     
  8. ianwood

    ianwood Taco Wrangler
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    That makes sense. As the props are turning, they are not moving forward, thus they are encountering more resistance. However, it is concerning that an RTF system like the P3 can actually overrun the battery. The battery should be able to handle full load on the ESCs.

    P.S. Good job digging into the logs to find out what was up.
     
    S5S5G6 likes this.