Voltage warning too early

Discussion in 'Cinestar 8' started by Bob Wojda, Jul 9, 2014.

  1. Bob Wojda

    Bob Wojda Member

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    Looking for help with the early warning voice system. We just recently upgraded firmware. Everything is working well but we get voice warnings coming on too early during flight, (at only two minutes). When we check batteries we have up to 60% remaining. I think I have the voltage settings set incorrectly either in mk tools or on the mx20 transmitter. I'm not sure what they are supposed to be so that we come down at 20% remaining. Can someone help?

    Bob
     
  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    Assuming you're using MK, and if you updated the firmware, you're familiar with MK_TOOL, right?
    When you do a firmware update, it reverts all your setting to the defaults.
    Go into the Misc screen and adjust the Under voltage to 34 or 35, then update the Flight Control.

    But are you 100% sure your battery is charged properly? No bad or marginal cells? Good internal resistance?
     

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  3. Bob Wojda

    Bob Wojda Member

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    Steve,

    Thanks for the quick response. I am using MK tool and I'll check these settings. We've had several batteries on it and no bad cells. Is there anything on the MX-20 that would send a low input voice warning too early as well? Not sure if something got changed there. Really appreciate your help.

    Bob
     
  4. Steve Maller

    Steve Maller UAV Grief Counselor

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    The mx20 is just parroting what the MK Flight Control tells it to do. Do you have a GPX file from one of these flights? That would certainly be helpful and might indicate what's going on.
     
  5. Bob Wojda

    Bob Wojda Member

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    Thanks Steve, Just checked the gpx file and there's nothing on the card. Not sure what's up with that either. I'm checking the mk setting now.
     
  6. Steve Maller

    Steve Maller UAV Grief Counselor

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    In order for the NC board to save its logs, the card has to be a 2GB (or smaller) card with the MSDOS file system. It's possible that you have the card formatted incorrectly. One of the settings on the FC board that I always set is to not start without a card installed (and obviously formatted correctly).
     
  7. Bob Wojda

    Bob Wojda Member

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    Steve,

    Just changed the Undervoltage settings in MK-Tool to 3.3 and ran a battery down. It went all the way to 3% before warning. Probably too much. Do you think 3.4 or 3.5 will get me close to 20% remaining?

    Thanks!
     
  8. Steve Maller

    Steve Maller UAV Grief Counselor

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    "20%" is tricky. I set mine at 3.5 (35) in MK Tool, but that's with my newer, better batteries. My older crap batteries (Zippy 6S) rolled off a cliff around that voltage so I had to set it higher (3.7V). So it totally depends. And better safe than sorry. AMHIK. :eek:
     
  9. Gary Haynes

    Gary Haynes Administrator
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    Bob 3.3 would be considered a dead battery. The good news is that if you got the warning while flying the battery will bounce back up with removal of the flight load. Check it after you land and there should be some recovery. I usually run at 3.5 or 3.6v for my warnings. Give a reasonable cushion and not try to fly the last amp out of a flight.
     
  10. Bob Wojda

    Bob Wojda Member

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    Gary,I agree 3.6v seems like the safe spot to run. Thanks for the help!
     
  11. Dave King

    Dave King Well-Known Member

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    I have mine set for 3.6/volt
     

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