Crash with x8 after low battery warning! battery still 40%

Discussion in 'Cinestar 8' started by Jason Smoker, May 15, 2015.

  1. Dave King

    Dave King Well-Known Member

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    Thanks. Well that puts a bucket of water on the idea that it was going into come home since its set to 19.8 volts.
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Don't you hate it when facts get in the way of theories....seems to happen a lot in my world of forensic software analysis. :rolleyes:

    Andy.
     
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  3. Jason Smoker

    Jason Smoker Active Member

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    Okzan and others what should i undervoltage setting at? I thought the standard was 3.6v for warning which my for 6s (3.6 x 6s =21.6?)

    I want as a warning so my lights flash telling its time to land.

    I will lower my comehome voltage lower on my other machine just in case
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    To quote Clint Eastwood, "Do ya feel lucky, punk?" :)
    Joking aside, I use a cell voltage of 3.6 -- gives me a nice margin of error to get home, loiter above the landing area just in case I get a wave off because a small dog or animal invades the area....

    Andy.
     
  5. Shaun Stanton

    Shaun Stanton Active Member

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    I know I am late to this post. Here are my observations with my X8. Because of the loss of thrust versus flat and if carry extra load the battery will sag to minimums quicker, especially if you really advance power. Because its a function of load voltage you actually may end up getting to warning state earlier and landing and finding out that the resting goes back up to a higher number. I have found that this has become true when the battery is getting weak and is probably not supplying the discharge C rating as advertised anymore. I can start telling that the battery is getting weak on my charger when my Hyperion starts telling me that the batteries internal resistance is above 20 mili-ohnms. Not sure how accurate that number on the charger in reference to the actual IR. On my charger I notice once its readout for internal resistance goes above 20 I can expect the battery performance to become very noticeable especially when flying max payloads. Ne batteries I find have an internal resistance around 9 or 10 miliohms and it seems to start slowly creeping up after 10 cycles.

    Not sure if that was your issue. But it is something I have noticed when I have flown the thing at 28 pounds of total gross weight with my setup.
     
  6. Jason Smoker

    Jason Smoker Active Member

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    Thanks Shaun, that batteries i was using where 6months old but still well under the IR there about 10 to 15 readings on the charger.
    They had well over 100 cycles on them in that time. (i usually exchange batteries every 6months or so anyway).

    I have since bought Tattu 6s 10000mah for the x8 and upgraded the motors and bigger props. Hoping these wont happen again
     
  7. Shaun Stanton

    Shaun Stanton Active Member

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    That's good. I bought a 12000 Tattu recently just to try it out. I have to say I am impressed with that battery so far. It seems to be more stable under heavy loads than any other battery I have had.
     

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