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Is it possible that DJI batteries lie about their capacity?

Discussion in 'Phantom 2 Discussion' started by Fyod, Apr 18, 2016.

  1. Fyod

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    I have been studying two of my dead batteries the last couple days. Both show 50% on the LEDs, but actually are at 10.8V and unsafe to fly. One had about 75 cycles, the other 55 or so.
    I'm sick of these inferior pieces of sh** and want to refurb them.
    I spent hours today looking for the correct size of battery and have come to the conclusion that you cannot find a 100x34x8mm cell that has a capacity of 2600mAh (3 cells = 11.1V pack, 2 packs = 5200mAh). All 2600mAh cells made by the best manufacturers are 13cm long (longer than the DJI pack).
    The closest is a Turnigy cell that has 2200mAh = 4400mAh pack. Thus I cannot see a way DJI could ram almost 20% more into the same size constraint.
    Those noname packs claiming 5400 and 6000 are even more questionable. I have extreme doubt that DJI or anyone else would have specially made cells that have a 20% higher capacity and the big manufacturers wouldn't make or offer them. ~20% capacity without changing size is a huge number in the world of batteries.

    Can anyone logically explain how any of these claims can possibly be true or show an example of a cell with the claimed capacity and same size?

    [​IMG]
     
  2. Fyod

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    Ok, nevermind, I found these Multistar packs http://www.hobbyking.com/hobbyking/...0mAh_Multi_Rotor_Lipo_Pack_EU_Warehouse_.html

    This then explains the problem though. With a 10C rated discharge, provided that the specs for the ESCs are correct in the 15A optimal current, 60A plus other electronics like the FPV Tx, camera, GPS etc., the low dischare rate (52A) is whats killing the original batteries prematurely.
     
  3. N017RW

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    Here, here, Fyod!!!

    Been saying they are of insufficient design (C rating) and not charged using the recommended CC/CV charge profile.
     
    #3 N017RW, Apr 18, 2016
    Last edited: Apr 18, 2016
  4. Fyod

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    The reason I couldn't find the size/capacity was that I was looking for 15-20C, although in the past in discussions I mentioned the discharge rate could be 10C. They were probably good enough when the Phantoms weren't carrying anything back in the day and were under 1kg total weight. But later when cameras, gimbals, and better ESCs were added, this is when the batteries began failing.
    Higher discharge rate = slightly larger battery.
     
  5. N017RW

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    Yes,

    Higher C rating = bigger, heavier, and more $.

    None of those is a plus when designing a flying camera.
     
  6. Fyod

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