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Shockingly poor flight time

Discussion in 'Phantom FC40 Discussion' started by chrisc, Jul 16, 2014.

  1. chrisc

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    I've just been outside timing my flighttime with the FC40 and it's abysmall.

    I'm running a FC40 with a Walkera G2D gimbal with FC40 camera and Mobius camera attached. Basically 5g lighter than adding a gopro.

    It's got the Vision props and Vision prop guards and I'm getting a whopping 4mins flight time out of it. I used to get ~8 mins.

    Yesterday I set the low voltage cut off to 11.15/11.0 and calibrated the voltage which was pretty much spot on anyway.

    After 3 flights with three batteries each battery came off at 11.5v after a matter of seconds.

    Do I need to increase the 0.6v voltage drop for load?

    What else could be the issue?

    - for clairty the quad has 2 x 5g packs of sugru on it for attaching cameras, flytrex and front led so minimal weight added.


    ---- EDIT ----

    Seems like I need to double check my settings before flying. The voltage was set to 11.15 (1) and 11.0 (2) for low voltage with voltage drop of 0.0v.

    If the voltage drop on load is 0.6v or so then I guess a resting voltage of 11.5v is okay after a flight that shows me 11.5v on rest as I'd guess (thinking out loud here)

    11.5v resting - 0.6v drop not set = 10.9v which could represent the 11.0v auto land kicking in.

    Maybe i'm just being a little bit special.
     
  2. chrisc

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    I'll reply to myself...

    Just been out with the newly adjusted settings of

    11.1 - 0.6v (stage 1)
    11.0 - 0.6v (auto land)

    and I got 7mins 25secs flight time. Mainly hovering but a few short burst of action. Not too bad considering it's about as fully loaded as it's going to get. I expect if I was at more than 6feet and it auto landed slowly It'd have probably got ~8mins and if you take off the prop guards I reckon it'll hit 8mins before it auto lands anyway.
     
  3. SimonH78

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    These are my FC40 s voltages with GS and H3-3D and flytrex fitted, and get 11mins flights.... std stock lipo.
     

    Attached Files:

  4. EMCSQUAR

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    Try this - lower first level to 10.8, second level to 10.6 and put voltage loss a 0.00 then you'll get your expected flight times. note lose the prop guards - not only will they kill the times, they make it more succeptable to wind. Great for learning but lose the training wheels.
     
  5. chrisc

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    EMCsquare - Those voltages are higher than what I'm at allowing for the loaded voltage.
    SimonH78 - Those voltages look rather low. 3.1V per cell looks like permanent damage territory.

    I will drop my first level warning a tad more and increase the loss to 0.7v. I don't think I'd be happy with the second level set as low as yours. I think 10.5 should do. Voltage drop off is rather rapid on these lipos once you get to a point.

    as for the training wheels, they're a pain in the bum and they are proper wind catchers but I get quite a few people ask to fly it and I'd rather it had them on for them.

    They'll probably come off in a day or two as I keep on meaning to grab the set of screws out for it but everytime I forget I simply say "that's for anyone else who flies it".
     
  6. general01

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    I have flown mine from day one with no prop guards

    Its a bit nerve wrecking till you get the feel of the craft

    My latest flights have been my longest
    I can even take off and land on the ground without tipping(that took some time to get mastered with my environment as its hilly)
    Its nimble without the prop guards
     
  7. SimonH78

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    That's good your getting longer flights, my cut-of is a MAXimum ... and rarely it only gets that low all my lipos are hard an solid as new and are a few months old now, are always balance charged... :D
     
  8. zerodb

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    Your second level cutoff does look pretty sketchy, but then again we can buy 2200mah batteries for $10-15 so who really cares if you wear the battery out a little early if it makes your flights more enjoyable?!
     
  9. zerodb

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    I've tried both ways. First time I hit a tree with prop guards on, it broke one of the prop guards.

    Hit a tree without the prop guards, no damage. Accidentally INVERTED and landed prop-side down on the driveway in manual mode, no damage.

    Broken props cost about the same as broken prop guards so I just don't see much point in it anymore.
     
  10. Lonewolf

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    There's been other comments on this topic regarding a crash prop-side down on a hard surface. Doing so can cause your GPS antenna to crack or break. They're ceramic and very fragile. Any time you crash your Phantom upside down this should be an immediate consideration. Open the Phantom housing and check the antenna for any small cracks. It's easily identified. It's on the very top and center. It's a small square. If it's cracked or broken, you're no doubt going to experience serious issues while flying because of no GPS signal.

    There are several youtube vids on how to replace/identify the GPS antenna.
     
  11. chrisc

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    So I took the prop guards off as I had a spare few minutes and checked flight time again.

    Went from 7:25 with a low level flight mainly hovering to 8:19 with a few bursts of speed and the prop guards do slow the bird down!

    I charged the battery up and put 1789mAh into it so I'm just above the 80% battery usage.

    I manually landed the bird at that time but it was starting to fight me to land elsewhere.
     
  12. Gizmo3000

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    Simon, I certainly hope you're landing immediately once you see the flashing red lights, otherwise you are no doubt killing the lifespan of your batteries.

    I most people never recommend going lower than 3.5per cell. (I have my 2nd level failsafe loaded set to 10.4, but I land much sooner). I've never even heard of someone setting their 2nd level down to anything under 10.
     
  13. Gizmo3000

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    if you're putting 80% of less back into the battery, you're doing just fine.

    7 minute flights might seem short, but thats plenty of time once you get the hang of it. (and have a few batteries)
     
  14. chrisc

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    Well at 8mins 20 flight time I can use my four batteries and have one fully charged again by the end of the batch so get 5 flights for 4 batteries. If I don't balance charge I can probably get the charge times down below 20mins by enough to have a constant cycle of flights. With the 5 batts (including charging the 1st) that takes me to 42 mins flight time. Not too bad. I could go for more but I might aswell save the life of the batts.
     
  15. general01

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    Don't fly in manual mode till you really know how to handle it in manual mode

    I thought of getting the prop guards for Indoor flights but its more fun outdoors(I only hover test indoors to make sure it doesn't act up before I get in flight)
     
  16. mikey

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    I just had a weird thing happen to me. Fourth flight. first three were successful at approx. 12min flight time, on the third flight I pushed it all the way to the final low level alert and the phantom descended on its on. no problems.

    during my forth flight (just now), I only flew for about 4 minutes. and then noticed rapid flashing red... I was close to the ground, and panic mode was for me to just softly land it myself (which I did). the red kept fashing until I turned the rotors off, the LED then went to solid green before I unplugged the battery.

    Is there another indicator (other than low battery) that flashes red during flight? I read through the pdf manul found on dji webpage, wow - what a lousy manual that is, they should seriously pay to have that rewritten, its down right pathetic. Anyway, I couldn't find my answer there, so I'm asking here.
     
  17. DownunderPhantom

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    Hi everyone,

    My first post here in the FC40 forum.

    I own both the FC40 and Vision Plus.

    The other day I had a 21min 30sec flight with the FC40 and before anyone asks, no it is not stock.

    I have put the guts of the original phantom into a phantom 2 body and use the Phantom 2 props. I have also configured it so I can use either the phantom 2 or the original 2200mah batteries. I also have the FC40 camera, and a Goodluckybuy gimbal with Gopro 3 black (not on the bird at the same time)

    In the heaviest configuration which is, GoPro with Gimbal and either Phantom 2 or two original batteries I was only able to achieve. 13min 20sec with the Phantom 2 battery and 14min 15sec with the original batteries.

    The phantom 2 battery still had some charge in it but the bird wanted to land early. On the P2 battery there are 4 led's which indicate how much charge is left, when the bird landed it was still solid on the first and flashing on the second led, I did not go in and check the remaining charge in the assistant software but will tomorrow.

    I have consistently been able to have 7-8 minute flights with GoPro and Gimbal with only one battery, the P2 props give it at least 2-3 minutes more flying time. Using the original props I was only getting about 5 minute flights

    With the FC40 attached only and running 2 batteries with standard P1 Props the max time I was able to achieve was 16 minutes.

    If anyone is wondering about trying non DJI props, do so with care, I have used P2 CF props and have had VRS twice, also with plastic 3rd party Props I found them almost imposible to control in GPS mode and very hard in Atti mode. For me the original props are the way to go.

    I forgot to say that I have not changed any of the battery settings in the assistant software, it is all default and I do not use Prop guards even though I have three sets.
     
  18. mikey

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    I am now officially having battery issues... flight four was approx 4 minutes... it was a strange flight, went to flashing red 4 minutes in.. I panicked of course and quickly landed, once the props were shut off and I picked the phantom up the led turned to green again... found it strange. it was getting late in the evening so I didn't look further in to it.. yesterday I allowed my 11 year old son to fly it as I watched from the deck. About 3 min in the phantom went straight to flashing red... what's strange is that he flew it with flashing red for another 4 minutes before it auto landed... is this normal? I'm disappointed I'm only getting 8 min fly time, 100% stock fc40, and the thing has only flown 5 times. Maybe I have a dud battery? I'm going to check my voltage levels before and after this mornings flight.
     
  19. SimonH78

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    If you leave the standard stock voltage settings in the "Assistant software" it will only fly a short time, these need tweeking down to the minimum allowable to get longer flight times...
     
  20. mikey

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    So you're saying stock fc40 is only expected to get 7-8 min? My first flight I was over 12 min, took the craft as high as I could till I could hardly see it... flew back and forth, twirled around etc. second flight was similar... third flight a little lighter.. all three flights were over 10 min, and the second two nearing the 12 min mark.. but my fourth and fifth both under 8 minutes?? something seems wrong to me..