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Low Battery - Second Level Warning

Discussion in 'Phantom 2 Vision Discussion' started by Klaus, Jan 4, 2014.

  1. Klaus

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    How come Low Battery - Second Level Warning is set to default 15%?
    Would it be unwise to set it down to 5%? That should still be enough to set it down safe or...?
    That would give you 10% more flying time!
    What are your thought about this? And how is your setting?
     
  2. Pull_Up

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    I just replied to a similar comment in another thread. Lipos don't like deep discharging. At best it shortens their useful life, at worse they can catch fire if they get too discharged! The rule of thumb with RC lipo use seems to be run down to around 20% most of the time and the lipo stays happy. Personally I have my first stage warning set to 23% and my second stage set to 17%. I always aim to land before second stage kicks in, and if for some reason I couldn't I would land it out where it is and walk over to get it rather than push the lipo too hard.

    At over £100 a go I want to cosset my batteries and make them feel loved and appreciated - and get at least the 300 flights spec'd life out of them!
     
  3. Klaus

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    Ok thanks that was an explanation easy to understand

    Sh....t After I was reading your answer I was thinking that I better take a look at the Disclaimer that comes with the PV. One of those thing I'm sure most people don't read, and I guess it's because most often people already know about those things written in there.
    But in this case, wow I can only advise everybody to read the disclaimer about the batteries :!:
    After reading it, I can't understand why they are used in flying objects????
     
  4. Drone7

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    This is one of the reasons it isnt a toy. I bet many people destroyed there battery because they didn´t read the manual and ask on forums why this happened.

    It is a good thing you ask before you do something and Pull_Up gave a very good answer.

    Buy a lipo safe bag if you want to be sure it is safe to charge. All of my lipo´s are stored that way and i have many.
     
  5. Klaus

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    Sh... this is getting worse and worse, now we have to buy a lipo safe bag to charge our batteries which needs charging all the time.
    I just saw a video on YouTube where they over-charged a Lipo battery, it just went up in flames :!:
    So how safe are our chargers??? Can I overcharge the Lipo's withe that charger? Or isn't a smart charger which stop charging when it's charged?
    Also when you are reading the Disclaimer it says:
    "It's recommended that batteries be charged and stored in a fireproof container :shock:
    "Do not expose batteries to excessive physical shock" What in a airborn object that can fall down any minute????
    It also say: "Do not charge above 4.2 volt per cell" But how can I know?
    I am actually not feeling very good about those batteries, and Im sure most people don't know about this.
    And you can't have them in you car on a hot summer day. I know they mean don't leave them in the car. But what do you do when you are out flying on a hot summer day, where do you have your spare batteries?
     
  6. iDrone

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    +1 precisely...

    The lithium batteries we use are Lithium Polymer's aka: LiPo's or "pouch batteries"; very lightweight for the power & capacity they hold. Lithium batteries -can- be ruggedized but this adds weight (steel, aluminum, ABS) and increases their cost. Pouch batteries are perfectly safe provided you understand how to handle, use, and dispose of them in a given product design. DJI has encased the pouch battery, charger, & smart circuitry in a protective frame which also has some shock absorption properties. The Vision battery cannot be overcharged or over-discharged when used with its own charger. If you periodically inspect the batteries for physical damage, punctures, swelling and properly dispose of them when they do, you should have no problems.



    Some RC'ers who purchase off-the-shelf LiPo's fast-charge them with LiPo chargers using their own charge/discharge profiles and will use fire-safe bags as a precaution, but keep in mind they're trying to maximize their flight-times & minimize their recharge times, pushing those batteries to their limits. I find Vision's power system has been very nicely designed to optimize flight times and recharge times while maintaining the longevity of its very expensive battery pack.

    And as Pull_Up said, LiPo's don't like deep-discharging if you want them to last so...
    "Live long and prosper..."

    iDrone
     

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  7. Klaus

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    Hmmm after I read your previous post I was reading more about, and everywhere they recommended the Safe bags so I ended up buying 4. But now after I'm reading your last post, I find that I maybe didn't have to do that? Do you use bags?
    Thanks for your always helpful and clear answer, much appreciated.
     
  8. iDrone

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    You're welcome, and no... no bags. One flameout, entirely my fault for manually recharging a weak LiPo and getting distracted for a few minutes, and all of a sudden I have the greatest respect for automatic LiPo chargers, SmartBatteries, and any product that is properly designed to use LiPo's. When they get old & puffy (like some of us) I discharge them properly, tie their leads together and send them off to never-never-land and buy new ones.

    iDrone :geek:
     
  9. Pull_Up

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    Just to add another feature, from the Assistant app it's clear that the battery also has a temperature sensor on board, so the smart circuitry can monitor it for excessive heat as well as over-voltage.

    Because the Vision is primarily aimed at non-RC savvy consumers DJI have actually put a lot of behind-the-scenes work into making the battery charge & fly & forget, without having to get involved with more complex smart chargers, balance leads, different charging rates, etc.

    It still hurts at over £100 per battery, but it's slightly more palatable when you take into account what it's doing for us to make life a little easier and safer. :D
     
  10. Drone7

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    It is not getting worse. Just do everything by the book and enjoy your flights.
    DJI has got good chargers and good battery´s and a good manual that people should read