Lipo Battery failing question

Discussion in 'Cinestar Misc' started by Ken Green, Sep 27, 2013.

  1. Ken Green

    Ken Green New Member

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    I have a QuadroPower 6200 4 Cell lipo battery that after it powers the CS8 to "undervoltage" minimum discharge, it gets fairly warm and puffs up slightly .... like there is trapped air in the plastic wrapping, but just on the top and bottom. When I lightly press the puffy part it feels like air but still has a solid feel when you press enough to feel the cells . The sides of the battery are not puffy at all. It still takes a full charge at about 16.7 v in about 45 minutes. Is this a sign of the battery failing. I have other 6200 batteries that do not puff up. Any one know what that might be.
     
  2. Gary Haynes

    Gary Haynes Administrator
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    Ken what is the percentage charge remaining when you start to recharge? If it is visibly puffing then likely the battery was over discharged at some point, less than 20% remaining and likely down at 10% or lower, and it resulted in damage to the cells.

    What do you have your under voltage warning set to?
     
  3. Ken Green

    Ken Green New Member

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    Just plugged in MK tools and see the under voltage alarm is set at numerical number of 34 ... or ... 4s 13.6 v
    I changed the under voltage alarm to # 35 4s 14.0 v
    I recall the puffy battery was around 13.5v prior to recharge. Too low I think ?
    The battery in question just charged to 16.78 v in 76 minutes.
    What undervoltage alarm setting do you use?
    Ken
     
  4. Gary Haynes

    Gary Haynes Administrator
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    I am pretty conservative at 14.6v. 14.4 would be ok. 13.6v likely damaged the battery. A dead battery is 3.3v (13.2V)
     
  5. Ken Green

    Ken Green New Member

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    Gary
    ....just flew two batteries ( 2 flights ) with the undervoltage alarm set @ 14v
    First battery alarm went off to 14.5
    Second battery went to 14.6
    Both flights were about 12 min. using the 6200mah battery
    no camera
    Normal ?
     
  6. Dave King

    Dave King Well-Known Member

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    I agree with Gary. I set mine to 14.4 and its never failed me in close to 350 flights.
     
  7. Ken Green

    Ken Green New Member

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    Thanks guys for the help.
    Just set the alarm up to 14.4 as well
    Ken
     
  8. Gary Haynes

    Gary Haynes Administrator
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    Ken we need to know what your charger says is the percentage remaining. What charger are you using? Do you have a lipo checker like the Extreme Power Analyzer PA-010 that shows percentage?
     
  9. Ken Green

    Ken Green New Member

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    yes ...I have a battery checker that reads total Volts and readings for each cell.
    IMG_0292-small.jpg
    I use the hyperion EOS 7201 charger.
     
  10. Gary Haynes

    Gary Haynes Administrator
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    On the 720i Duo you can see the percentage remaining very easily. When you plug into charge check to see what percentage is there. If less than 20% you may be damaging your batteries. I don't have the 720i anymore and forget which keys will get you to the screen. Should be in the manual or someone like Andy can tell us quickly what to press to get the answers.

    From my charging log 20% is about 14.95 volts or so.
     
  11. Ken Green

    Ken Green New Member

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    Thanks so much Gary ! Have reset the low volt warning to 14.4v ... so shouldn't be a problem any more.
     
  12. Jim Swanson

    Jim Swanson Member

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    I set mine to 14 volts under load. Below 14v I get a warning and land immediately. The voltage drop is only for a split second and goes away when I ease off the throttle. Usually the resting voltage upon landing is 14.7 - 14.9.

    Is this your experience...resting vs under load?

    jim
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Jim: Have a look at the LiPo tests I did -- second document at http://rathergoodguides.com/documentguides.html

    You'll see that the LiPo voltage rebounds significantly when you remove the load. You are dicing with death to have the voltage alarm at 14.0 -- the decay from 14.0 downwards can be fast enough to make your eyes water. I would urge you to set it to 14.4v and allow yourself some "come home and land in a controlled fashion" time. Low, fast, high speed lateral landings are impressive, but it's incredibly hard to sustain the illusion for DPs, and other film crew members, that it was deliberate and you really meant to have it happen that way... :)

    Andy.
     
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  14. Dave King

    Dave King Well-Known Member

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    I have the 720 duo and I don't see percentage remaining.
     
  15. Gary Haynes

    Gary Haynes Administrator
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    Should be the first view when you are in balancer quick view mode. % above TCS.
     
  16. Jim Swanson

    Jim Swanson Member

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    Thanks Andy,
    As usual your way ahead of most of us. The 14v number was the setting used by Jeff at Quadrocopter in one of his videos. I've just always used his number. I think I'll change to 14.4 to be safe...rrrrrrr.

    jim
     
  17. Ken Green

    Ken Green New Member

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    GREAT info everybody ... thanks so much.
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Jeff is a far better pilot than I am -- and he actually can make a low, fast, screaming, heebie-jeebie, panic-stricken, approach look like it was deliberate without frightening the client, the DP, and nearby horses..... :)

    Andy.
     

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