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Best way to Discharge Battery

Discussion in 'Phantom 2 Discussion' started by pianoflyer, Mar 19, 2015.

  1. pianoflyer

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    Hi,
    Just wondering. If I have a fully charged battery and realize that I am not going to fly for a few weeks, do I need to discharge it? I thought I read that it is best to store it at about 40% charged.
    If so, what is the best/safest way to discharge the battery. I also heard it's a good idea to discharge it after every 20 flights. Do they mean just fly it until you have 1 light on the battery....or what is a better way?
    Thanks
     
  2. thestone11

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    If you have the newer version of the battery. They have an auto discharge function built into the battery. If the battery remain untouched for 10 days, it will start discharge itself to storage level. Flying is still the fastest option though, when the weather is bad outside and I have a full charged battery for more than 48 hours. I usually just hover it in my garage to drain the battery down.
     
  3. jason

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    Discharging methods::
    1)Slow
    Place battery in Phantom and turn on. Leave on until there is less than 8% of power left or until the battery can no longer be turned on. See DJI VISION App for battery levels. Motors do not need to be turned on, reducing wear.
    2)Quick
    Fly the Phantom outdoors until there is less than 8% of power left or until the battery can no longer be turned on.
     
  4. gword256

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    8% is extremely low for a storage state on a lithium ion battery. 40% appears to be the sweet point for storage. While DJI says do a deep discharge every few cycles I have never read anything to back this up.

    Ref. http://batteryuniversity.com/learn/article/how_to_store_batteries

    That said. I use the slow discharge method to drop below 75%. It takes a few hours 2-3.

    For extended storage you can put it in a cooled area (fridge) but when you take it out make sure there is no condensation on it before use.
     
  5. jason

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    The point was in how to discharge the battery not necessarily down to 8% without turning on the motors as the LEDs will indicate when 50% has been reached. Besides that method new batteries have an auto discharge feature in there software an after 48 hour of non use will start to discharge down to 50 - 40% over time. Also if you were lucky enough to have updated all older batteries with v2.6 battery update when v3.6 firmware first became available those batteries would also have the auto discharge feature.

    Myself I make it a habit to discharge all my batteries down to 8% before recharging them which is no big deal since fly them down to 15% in the field. Normally when discharging a battery I do it while P2 is connected to the software where I can monitor it while I'm editing footage. Again when they are at 15% in the field it doesn't take long to reach 8% while monitoring them.
     
  6. gword256

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    Personally I'd even avoid going down to 8% at all. The deeper you cycle a Lithium Ion batter the shorter the life.

    http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

    See Depth of Discharge in that link.
     
  7. Monte55

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    Just a thought. You could say you are downsizing and have to let them go. Nothing personal.
     
  8. adanac

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    I think it would be better to use the primer I'll link below as it is specific to the flight lipo's we use, although one small difference is that most lipos don't have the "smart" electronics as the DJI batteries do, so some small parts of this primer don't apply. Still, this is a great explanation:

    http://www.multirotorforums.com/threads ... ies.12072/



     
  9. gword256

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    It's that smart technology that needs the deep discharge to 8%. It's a calibration thing actually.
     
  10. Marlin009

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    This seems to work well. Those are two 4# soft dive weights laying across the landing gear.
     

    Attached Files:

  11. adanac

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    Can you elaborate? Where is there more information on that?


     
  12. Protocrash

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    Hey guys - being into RC for decades I know what it takes to take care of LiPos. So I was amazed there's no proper way to bring Phantom batteries to a correct storage level quickly (their auto-discharge takes a minimum of 3 days which is not fast enough for me). So I created a little gadget to do just that. I call it the Phantom Angel and I bulk ordered the boards so that I can provide (almost at cost) to anyone who's interested. More info at Phantom battery discharger