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Conflicting battery charging info

Discussion in 'General Discussion' started by JRUSH311, Sep 6, 2015.

  1. JRUSH311

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    I'm on around 8-9 flights on my p3a
    I'm a little confused on the battery charging habits recommended

    I read in the manual that you should occasionally discharge the battery to 8%

    Although in other areas it says NOT to discharge below 20%

    So to be safe I return my craft to the ground very shortly after the 30% warning

    What if the the battery is at 50%
    Is it ok to charge it back up from there?

    Does it have to be down to 20% before being plugged in?

    I've learned the software and controls rather well but the battery is a gray area
     
  2. Meta4

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    Yes .. of course.
    You don't want to be taking off with only 50% in the tank.
     
  3. notelpats

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  4. tcope

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    Simpy recommendations for two different things. Normally you don't want to drain the battery below 20%... certainly not during normal flying. But every 20 flights or so you may want to drain the battery down to 8% and then immediately charge it back up to 100%. No lower than 20% while flying as this allows you to land safely but down to 8% every once in awhile as this allows the Lipo battery to cycle or charge/drain correctly.
     
  5. RoyVa

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    It is always recommended to take off with fully charged battery. And yes you can charge a lipo up from 50%.
     
  6. JRUSH311

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    Ok good info
    I just recall reading that discharging below 20% could permanently damage the lipo battery which conflicts with the 8% every 20 flights suggestion
     
  7. notelpats

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    From what I have read, never fly below 20%. Land it above that and let the battery slowly discharge with aircraft on for your every 20 flight deep discharge.
     
  8. mikegraves54

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    Lithium batteries have a memory of sorts. I tell my computer science students that once a month they should discharge the Lithium batteries in all of their devices (lap tops, phones, tablets, digital cameras, etc.) and then fully recharge them. That way their batteries will not loose their total capacity earlier then normal. That said I believe the P2V batteries have a life expectancy of 33 hours.
     
  9. jjfromaus

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    Hi JRUSH311

    Just my opinion of DJI smart LiPo battery charging and discharge routines.
    DJI has a "smart" battery management system, however it seems as if the balancing charge part of the battery is shared with the cells connected in parallel in the DJI pack.
    This presents a problem with the parallel connected cells, which means it will average "balance" charge the parallel connected cells.
    I have taken careful note when discharging my DJI smart batteries, the cells differ in voltage according to the DJI APP stats when the battery charge is above 18%.
    Now any experienced LIPo RC enthusiast will emphasise that one must balance charge your batteries often to increase the life expectancy of the cells and to avoid a inter cell currents due to different voltages of the cells. The only way DJI can " balance " the parallel cell voltages would be to discharge the battery to a low charge voltage and hope it will relieve the voltage disparities of the battery pack after recharging it back to 100%. This practice takes chunks of life out of your battery.
    Refer to Yorlic's posts on DJI battery data and you will find some interesting reads about LiPo's posted there.
    Happy Flying :)
     
  10. RoyVa

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    DJI'S position is during normal flying land at 20%. Then for every 20 cycles not every 20 flights. Cycles per the assistant in the battery tab. Lower the battery charge to 8% then fully recharge the battery back to 100%. Don't let it set at that low of charge for to long. 8% back to 100% helps to balance the cells back out. Only do this once every 20 cycles.
     
  11. JRUSH311

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    Well I flew and got 20%
    Then I let it hover around 1-2 ft off ground
    When I saw 8% I was gonna set it down but it landed itself in a very quick motion

    I had already cancelled the auto land
    It dropped quick luckily I was not very high
     
  12. RoyVa

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    At only 1-2 ft off the ground I doubt the altimeter was able to distinguish it's actual height so it shut off think it was at ground level. Just my two cents. If you take off an hover close to the ground you will see their is an error in the altitude by a few feet.
     
  13. notelpats

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    Land it at least at 20% than just leave it there turned on until you get to 8%!