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FC40 battery notification or voltage

Discussion in 'Phantom FC40 Discussion' started by fc40boy, Aug 20, 2014.

  1. fc40boy

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    Hello,
    I'm new in here so I have a couple question regard of my new FC40. I knew when FC40 battery voltage is low, it automatically landed right where it is which is dangerous of being lost. I wondering if there any other method to get a reading of battery during flight so I can get an idea when my battery is low so I can return home safely. Thanks
     
  2. lake_flyer

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  3. deltamike

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    The following chart was created by a friend in aero electrics.

    I find it handy.

    [​IMG]
     
  4. J.James

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    Ya way better to use a battly buzzer set to ware you have plenty of warning to still have time to fly back home and land it safely and turn the way way not cool internal low battery level alarm off so it dont auto crash on you when it trips the low battery level.

    the battery buzzer alarms are much more easier to here then it is to see the led on the back of the fc40 is. The buzzer thing sounds like a truck backing up and you can hear it from real far away. I can have mine so far I cant even see it but I can hear the piercing sound of the alarm going off.
     
  5. lake_flyer

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    Thanks! very handy indeed. And thank goodness, if I understand it right, my levels are safe according to this chart. I let my 12.5-12.6V Lipo's drop as low as 10.00 loaded. I see I can drop them to around 10.05, if the minimum safe level is 80% of full capacity.

    I assume these are unloaded values so I could even drop it 0.60 (meassured load) below that, to say 9.5 unloaded and still be out of the danger zone.

    Am I correct?

    (edited because I had the numbers mixed up)
     
  6. lake_flyer

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    I am thinking about shutting off the alarm levels as well. The second level auto landing is a stupid and dangerous thing. They should add the option to do a RTH as soon as the first level kicks in. I asked DJI for it and (probably coincidently) they added it to the V2 3.0 software recently. Let's hope they apply it to the V1 and FC40 as well.

    I have set the Lipo buzzer well ahead of the first warning. I timed a RTH from 300m up and 150m out yesterday. Took almost 3 minutes before hand catching it. I've set the first level at 10.50 loaded (if I remember correctly), second level 10.00 loaded, and the buzzer at 3.6, which gives me just about the 3 minutes I need to land as soon as I hear the buzzer. But sometimes I get less time, so towards the end of a flight I always take it closer and lower. It is much too exiting to hear the buzzer in the distance, knowing that it still takes that amount of time to get it down. And descending by hand in a hurry from that height is a great recipe for a uncontrolled drop and crash.
     
  7. deltamike

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    H'mmm. Getting complicated but say you have 10 batteries and you don't use them for 2 weeks. They will all self discharge to some extent. This is where a mutimeter comes in handy to measure the voltages, but it does not make any difference what the start voltages are. Some will be low so you get shorter duration and others will be higher and therefore, a longer flight time.

    On my battery test flights I think the lowest start voltage was 12.54v while the highest was 12.74 (Without looking at my thread) but whatever the voltage I would not drop any lower than 81% - I know - because in my experimentation I took a battery to 80% on the chart and wrote it off.

    I plan to experiment with the 4000 mAh soon and I will enter the findings on :-

    viewtopic.php?f=20&t=23071

    to test duration, although I had one flight with the 4000 mAh battery that gave me 14 minutes on the same setting as my 9 minute flight of the 2200 mAh.

    PLEASE NOTE :- The chart is ONLY APPLICABLE TO 11.1 VOLT BATTERIES

    Regards
    Pete
     
  8. lake_flyer

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    Just checked in the software and for a 3s the lower value you can set is 9,40 loaded with 0.60 load. Which gives me the idea I'm correct.
     
  9. lake_flyer

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    Thanks! I am not going to take them any lower than 85%-90% just to be sure. I figure that taking them to the limit of 80% regularly could damage them, AFTER reading your post. My initial levels are OK like they are. Not going to mess with them any further.
     
  10. deltamike

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    Just as an adage, not all Li-po batteries 'go' suddenly - they do - though, if you take them down to 60% but most people take them down to maybe 80% or 78% but the damage is done. They will still charge up and over a relatively short period of time the will expire so you have to set the limit to a minimum of 81% for the second level warning in the Naza voltages.

    Pete
     
  11. lake_flyer

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    85-90% is way too high, I have to correct myself.

    But this is a quite confusing matter, at least for me. I am looking in the software at the voltage page, with your friends chart next to it, and now it is finally starting to make sense. I could drop a 12,6V to around 82-83% which is 10,40 (unloaded) or 9,80 loaded. So I leave it at the 10.00 loaded, the extra 20 seconds is not worth it.
     
  12. deltamike

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    I am itching for the test flight tomorrow of the 4000 mAh.
     
  13. lake_flyer

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    I am looking forward to your results.
    Thanks for sharing your info. Has been a great help.

    Have a blast tomorrow :)
     
  14. deltamike

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    Thanks for your comments.

    Its great to have feedback.

    Meanwhile - rain stopped play.



    Pete