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Understanding RC LiPo Batteries

Discussion in 'General Discussion' started by RichWest, Apr 11, 2015.

  1. RichWest

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    I found the following write up interesting and felt it was worth sharing, if of interest to you...

    http://www.rchelicopterfun.com/rc-lipo-batteries.html

    And then there's DJI's Smart battery (Phantom 2) care recommendations, if you haven't read them:

    http://wiki.dji.com/en/index.php/Phantom_2_Vision+_Preparing_the_Battery

    My search originally was addressing Li-Po batteries and expected life. I'm starting to experience 14 minute flight times, 18 minutes was the normal two months ago and prior. Have no clue as to cycle count or battery life % at the moment, but will pay better attention into the future.

    Edit to add: I have about +70% battery life left on three batteries. Strange that one of the original batteries is showing +80% life, whereas a newer one is showing +70%.
     
    #1 RichWest, Apr 11, 2015
    Last edited: Apr 12, 2015
  2. IflyinWY

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    Hey Rich,
    Have you clicked my signature link yet. You can get to the battery page there. Mine isn't much but there is a link to a Texas A&m doc which is very informative.

    There are current vids which inform you about how to treat a LiPo. It's kinda like a wife... That's another story.
     
  3. N017RW

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    They're not being charged using the proper CC/CV profile.

    If you monitor the voltage during charge you'll see a slow ramp-up to 12.6v or so then the charging stops.

    That's not a CC/CVprofile.
     
  4. RichWest

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    I had been to your website, but your link in sig didn't express Li-Po life/care... The TAMU document is procedural for student researchers at their campus facilities. I doubt it's being updated, but yes it is a valuable resource.

    Thanks for adding to the content.
     
  5. RichWest

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    Are you saying the DJI charging profile is incorrect? If so, what can be done to remedy?
     
  6. N017RW

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    Rich,
    Based on monitoring pack voltage during charging it is not CC/CV.
    That's my opinion. I encourage others to Google it.
    Nothing can be done. The smart system is not user adjustable.
     
  7. RichWest

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  8. hychewright

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    Very good !!
     
  9. ccase39

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    I don't get this part about 75%. Do they want me to turn it on and use the Phantom until it is below 75%?

    Hints and Tips:The Smart Flight Battery can be charged using an optional Phantom 2 Car Charger. This can charge the battery in-car or through 3S-6S Li-Po batteries. Contact your authorized dealer or DJI customer service for details.

    Important´╝Ü

    • (1)Battery should only be charged with the charger provided by DJI. DJI does not take any responsibility for damage caused by third party chargers.
    • (2)If current battery level is over 75%, the battery should be turned on before charging.
     
  10. Mako79

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    I've had 3 batteries go back after 30-40 cycles.
    One thing I did in common was to discharge to 8% on the 20th cycle as per DJI instructions.
    Now my local RC guy says this is the dumbest thing you can do to a Lipo. He says to land when have 25-30% remaining and never go below. He has been flying helis for years and his cheapo batteries are easily over 200 cycles.

    Some others (on this forum) have stated that the only reason for the DJI 8% 20 cycle rule is to "re-calibrate" the smarts in the intelligent battery so it reads accurately. This is stupid as I prefer a functional battery over trying to correct some blinking lights and battery stats.

    I still think its a conspiracy to damage the battery. DJI's battery is a cash cow considering the 3 month warranty and the ridiculous price.
     
  11. RichWest

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    Doesn't have anything to do with running the battery down to 75% or being/running in the Phantom.

    It's about battery charging. If your battery is over 75% charged, it won't allow it to be charged as normal. You have to turn the battery on to override this limit and then you can charge to full.