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Low Voltage Warnings?

Discussion in 'Phantom FC40 Discussion' started by IrMarky, Feb 2, 2014.

  1. IrMarky

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    Hello,

    Recently I purchased the Phantom FC40. Upon take off on a fully charged battery, the low voltage warning LED's kicked in 5 seconds after take-off, the Phantom automatically landed. Here are the stock settings:
    [​IMG]


    After I adjusted the stock settings to First Level - 11.10V and Second Level - 10.90V I am getting around 5-6 minutes flight time, what could be wrong? would it be safe for me to lower these voltage settings some more as flight time is still little with no load, I haven't attached the camera yet.

    Thank you! :D
     
  2. havasuphoto

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    Do you have a way of checking the voltage of the battery? See that button that says "calibrate"...use it, and calibrate the reading so it matches what is in the battery when you take the reading.
    Do NOT lower your 1st level battery warnings!!! Sounds like your voltage level is not calibrated correctly.
     
  3. IrMarky

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    Hi,

    I don't have anything to take the voltage reading other than what appears on the assistant software. (Current Voltage X3)
    The image above are the stock settings that warn me 5 seconds after take off of a low battery, somebody told me to lower these settings to First Level - 11.10V and Second Level - 10.90V. The flight time improved a major amount, 5-6 minutes.

    Do you think their could be a problem with my battery? It's brand new, or a problem with the naza? Is it safe to keep the settings at what they are now?

    Thank you in advance. :)
     
  4. havasuphoto

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    You need to purchase a voltage checker. They're cheap.
    What does the voltage reading say, when you place in a fully charged battery? It should read around 12.5 volts.
    Let me know what it reads with a fully charged battery, and reset your battery level warnings to default please.
    You may have a defective battery.......
     
  5. IrMarky

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    Hi,

    That is correct, at full charge it is about 12.5V.
     
  6. havasuphoto

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    OK, and in the greyed out box that is reading the current voltage-it say's 12.5??
    Do you have more than 1 battery? I have a sinking feeling you may have a battery that has a bad cell in it(they have 3 cells). And, the only way to check this is with a Voltage checker for LiPO batteries(you plug the balance plug into the checker).
    This is the exact model I have;
    http://www.amazon.com/CellMeter-7-D...91371629&sr=8-1&keywords=lipo+battery+checker

    I would not fly, until you get things sorted out.....please, put your 1st level warnings back to default, and don't change your 2nd level warnings at all. You're still new(is)?, and I don't want to see the next post-where your Phantoms engines just stopped, mid-flight and the aircraft smashed to the ground.
     
  7. IrMarky

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    Hi,

    If I charge on 3A the battery will charge then the cells will balance for hours, although if I switch to 2A the battery will fully charge and balance within 2 hours.
    Could this be another sign of a defective battery?

    Can I use this voltage checker? http://www.heliguy.com/Extras/RC-Helico ... LED-Meter/

    Thanks in advance. :D
     
  8. havasuphoto

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    Yes, you can use that checker if you want.
    The normal charging rate of a DJI battery is 1.8 amps. So, even if you put it on 3, it will still only charge at 1.8. It is recommended to only charge at 2.

    Also-what accessories do you have on your aircraft? FPV, gimbal, prop guards? Any of these things will add weight to the aircraft and shorten flight times. But, I'm still thinking you have a battery with a bad cell. I got 1 out of 4, that was bad from the start-and couldn't even be charged. It's been 2 months since I returned it, and I'm still waiting for a replacement from DJI.
     
  9. IrMarky

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    Hi,

    I just have the FC40's camera mount attached, nothing else. I have not attached the camera yet... I will order a new battery this week and see if that makes a difference... When checking the voltage with that meter, what should I be looking out for, if I have a dead cell.

    Thank you in advance. :D
     
  10. havasuphoto

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    Your total voltage should be at least 12.5, and each cell should be around 4.2 volts....if you have 1 cell that's down in the 3 volt range, and 2 that are up in the 4 volt range-you've got a problem.
    Beyond that-I can't help until you get a voltage checker. Your normal flight time should be around 6 to 8 minutes, I would think.
     
  11. IrMarky

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    Thank you dude... I will buy a voltage reader and new battery.. will let you know the outcome.
     
  12. havasuphoto

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    Batteries are cheap....buy a lot, and have a lot of fun ;)
     
  13. IrMarky

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    UPDATE:

    Voltage meter has arrived.

    Here are the results:

    Voltage: 12.3V
    Cell 1: 4.05
    Cell 2: 4.12
    Cell 3: 4.17
     
  14. havasuphoto

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    That's a good battery. But, put it back on the charger. It should have a minimum of 12.5. Even when it lights up green and stops charging-check the voltage, if it's still low, put it back on for a bit more. Ideally you'd like to see 12.7. By the time you do the "compass dance", and wait for home point to be logged, you will be at 12.5 on take-off.
     
  15. IrMarky

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    That is correct, fully charged around 12.6V. I have done the compass dance but again seconds after take off I have the battery low warning and the Phantom automatically lands.
    If I lower the first and second level voltages in the smart system, I will get a lot more airtime, but I know I shouldn't need to do this.... any more ideas??

    Thanks again for your help.
     
  16. havasuphoto

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    Yea, buy another battery.
    I have no clue why your phantom only flies for seconds then lands. Load the default file from DJI, and see if that helps?
    Are you trying to carry a very heavy load??
     
  17. IrMarky

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    I have nothing attached, no extra weight at all. What do you mean buy the default file? will this mess up any settings? where can I find this?


    Thank you :)
     
  18. havasuphoto

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    I don't know what you have for settings. I would just leave the low voltage warnings at their default settings. If you can't fly for more than a minute or two-you've got bigger problems that I can't help you with.
     
  19. IrMarky

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    Okay, so with a new battery and the old battery I tried removing the blades and powering it up, full throttle with stock settings on the voltage protection.... NO FLASHING RED LIGHTS! so this means that something must be wrong when it's off the ground and the blades are spinning? could it be a broken compass causing this? hmm....
     
  20. havasuphoto

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    How could you have a broken compass with only a few flights?
    Also-are you sure you're not confusing the flashing red light with something else? You will get at least 1 flashing red light if you fall below 6 satellites in GPS Mode. Also, if you put the aircraft in Manual mode-it will flash red(don't do that).

    Compass calibration will be just yellow flashes, or yellow and green. But, you normally do the compass dance before any first flight, right?? you should.....
    After that, pull the battery plug(reset), and put it back in, and just leave the aircraft alone for about a minute. You should see rapidly flashing green-indicating it's found home lock. That doesn't necessarily mean it has all 6 satellites. If you're still seeing a red flash, just wait. OR, you can fly in Atti mode, where you will get green followed by a yellow flash.