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When to Fly.

Discussion in 'Pro/Adv Discussion' started by delirious, Jul 1, 2015.

  1. delirious

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    A couple of issues I have observed have come up that has caused people to fly and crash. One is battery issues and the other is GPS loss. I can't include everything but here are a few things you can do to help prevent fly-aways and battery malfunction.

    1. Always fly your batteries at 100% and freshly charged. The battery gauge is not reliable enough because of limited technology to tell us what the actual percentage is. It's probably more accurate on a battery that has been freshly charged rather than one starts at 95-96%. Which will not make sense to most people. People think 95% is absolute when in fact it is not. This is a limitation to calculation in lipos.
    2. Rely on voltage per cell. This is really the actual charge per cell you see. Most lipos start at 4.2 volts per cell at max charge. If you start at 3.89 volts per cell, then it is not far from fully (safe) discharged value of 3.5 volts. I know when I recently ran my phantom 3 battery down to 5%, it was at 3.5 volts. That was to cycle the battery. When I fly my helicopters, I always check the the cells with a little meter I have in my pocket. It doesn't tell me percentages, it tells me volts per cell and I want to see 4.2 volts per cell across the board, or I send it back to the charger for a balanced charge session. All it takes is one cell to botch the battery. People are seeing where batteries are dropping from 50% to 8% very rapidly. Note the charge per cell before flying.
    3. Do not let a battery sit for days fully charged and then go fly. Charge them up that day, prior to flying. That means activating or starting the battery and topping it off to 100% until the battery shuts off in the charge process
    4. Do not update firmware and then go fly. You won't have a battery that is 4.2 volts per cell
    5. Do not calibrate the IMU and then go fly. You won't have a starting voltage of 4.2 volts per cell
    6. Do not let your battery sit in excessive heat or cold and then go fly.

    Regarding GPS

    Do a calibration on the first flight of the day. Every time you fly. Doesn't matter if you change locations or go to the same place. You need the most current conditions on the compass. Atmospheric condition, location, metal objects, power lines, can all screw up the compass. Even a magnet can. Do this on your first flight.

    Check the mod value. It should be around 1500 and not deviating largely. CHECK THIS BEFORE EVERY FLIGHT!. It only takes a second to go look at the sensitivity setting. I've asked Bladestrike to see if the pilot app can show the MOD value on the home screen. It would be nice to have it labeled green for go or red for out of range. This would help prevent many flyaways.

    Take off and hover for no less than 5 seconds before you go off and fly. Make sure you are stabile and the bird is being kept in one place in GPS mode.

    Learn to fly atti mode. The moment the phantom is not responsive like it's supposed to be, shift to atti mode and keep it there. Learn how to fly this way and land it. I've started to fly mostly ATTI mode and I think it adds security. For pictures or landings, I shift it back to GPS. But I'm always making sure it's holding position prior to landing.

    At your own risk. I learned how to hand catch. Seems like the most controlled way to stop the phantom. Maybe not the safest.

    Good luck.
     
    #1 delirious, Jul 1, 2015
    Last edited: Jul 1, 2015
  2. briana

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    Thanks, useful stuff.

    Where do you put the meter probes to test voltage per cell ?
     
  3. delirious

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    Look in your pilot app in the battery section. It will tell you.
     
  4. Mike Hawk

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    Sorry about the newb question, is the mod value in the IMU grid?
    Thanks for all the other valuable info.
     
  5. JonasHess

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    Where in the app do you see mod value?
     
  6. delirious

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    Click on the main menu, Drone tab on the top, then sensor settings. Sorry, I don't have it in front of me. But if you haven't done this already, You should.
     
  7. delirious

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    1:43 is sensors
     
  8. Retired Pops

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    I hate to ask and I've searched the help section.( maybe someone needds to tell me how to search) You mention the MOD value being 1500? I have looked in the pilot app but haven't found it. What is MOD and how would I change it. Sorry to ask. To search I went to the search icon and typed MOD values
     
  9. Bigdz

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    Go here ImageUploadedByPhantomPilots1435775907.085147.jpg

    Click sensors
    ImageUploadedByPhantomPilots1435775960.694226.jpg
     
    Jaime Andrews and Retired Pops like this.
  10. delirious

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    I've seen it explained as the compilation of the X,Y,Z coordinates. It's the sweet spot for the compass and when calibrated correctly, will be near that value

    I'm no expert on all this. It's what I've gathered by reading every day. Out of 145 flights, I've had one fly away occur shortly after lift off and it was my error. I flew near a large metal building and didn't check the Mod value that one time. I switched to atti mode and lifted up high, recovered orientation, landed. recalibrated, flew just fine.
     
  11. JonasHess

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    I see 3 mod values one for gyro, acceleration and compass. Which one should be 1500?
     
  12. Mike Hawk

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    Thanks man, I have a lot to learn, wish I knew how to do the app screenshots
     
  13. delirious

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    Compass
     
  14. Retired Pops

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    Thanks I see it I'm taking it should be 1500 or higher. Mine is 15200 and changing all the time up and down a little
     
  15. delirious

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    1500 give or take. and small fluctuations are normal. Due to electromagnetic fields.
     
  16. damitjim

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    15200 or 1520?
     
  17. RyanK

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    What exactly IS the mod value??

    Also, I've read you're supposed to run down your battery to about 8% every 20 charge cycles or so. What is the best way to do this . . . I'm thinking after you get to 20% battery left, just hover in place at low altitude until you're at 8%??

    And lastly, as a scenario, say you're not going to be flying for 4-5 days and you just got home from a flight. Do you charge them a little (say to around the halfway point) or not charge them at all?? I'm confused as to how the recommendations you're making will work in real life.
     
  18. delirious

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    I've already described what the mod value is above

    Discharge battery by holding position 2-3 feet off the ground until 8% and then land. Or land and then turn on props and wait. Takes longer.

    If you aren't going to use them after a flight, leave them as is discharged and charge them up right before a new fly day. Discharged doesn't mean 0 volts. It means the battery has reached a safe level of storage. Around 3.5 volts. Rule of thumb is to not let lips go below 3.5 volts. You can check voltage in the app with the phantom turned on
     
  19. Whyler

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    This thread has great info for us noobs. My Pro came last week, and I've got some good tips from my mom who has a Pro also.
    I noticed on the DJI video in this thread that the ipad has its left side closest to the transmitter. One of the tips I got was to put it the other way around so the magnetic side faces away from the transmitter. Is this really a concern or not so much? Thx.