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Broke the 15min FPV mark today!

Discussion in 'General Discussion' started by DeweyAXD, Aug 29, 2013.

  1. DeweyAXD

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    So with all the fun of my new T8J I have yet to talk about my dual battery test.

    My Hero3 is in Holland being replaced under warranty (overheating!) so I thought it'd be a good opportunity to just try a pure FPV flight. I hooked up the cam that came with the Fatshark Predator along with my Dual battery/FPV setup (shown here):

    [​IMG]

    [​IMG]

    I still need some SpiroNet antennas (Badly!) but I was amazed how good the little camera was in the goggles. Don't get me wrong it is no Hero3 but the goggles have a set resolution so you will of course only ever get a certain quality of image.

    I had the 2250mah NanoTech in the shell and the stock 2200mah DJI batt in the cage (it has run a fair few cycles!).
    Using the T8J's timer I got a whopping 15mins 22 seconds of flight in moderate wind using GPS mode before the Red lights kicked in. This was a real time flight too (not just a hover). Flying over fields between 10-200ft roughly (CF props make a world of difference!).

    Final battery voltages after the flight/drive home:
    - NanoTech 2250mah = 11.18v (c1= 3.70, c2=3.69, c3=3.71)
    - DJI 2200mah = 11.29 (c1= 3.73, c2=3.74, c3=3.75)

    These IMO are in a nice safe zone. The green light was flashing after landing (I have stock voltage limits in the Naza). Probably another minute safe flying.

    Without the weight of the Hero3 the Phantom was nicely lively and with some SpiroNet antenna and the T8J I could easily do a nice 700m - 1km flight. I probably wouldn't push that far due to breaching the LOS rule (though some would argue any FPV goggles break that!).

    Still for those that love FPV for just the fun of the flight (and not recording it in HD) this really felt like a good combination. I am convinced enough by it that I will be designing a bigger cage to house my second NanoTech (adding 34g weight to today’s rig). Due to the weight I doubt I will ever get 20 mins but 17-18 looks a real possibility.

    Oh and to end on an entertaining embarrassing note - Smart Cars... they are bloody handy for Phantom flying! I usually take my Impreza but took the Smart today (my business'mobile as i call it). The drop down tail gate made a great setup table - just like a Range Rover :lol:
     
  2. marcus_canada

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    That's very cool my friend. I'm wondering whether to go dual batteries myself... Do you have a link for the dual battery mount system you use?
     
  3. mroberts

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    So the aft CG due to the battery didn't affect it?

    Is the Phantom largely insensitive to CG location?
     
  4. DeweyAXD

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    Yep the link to the parts is in my signature. If you are just looking for a dual battery setup with no FPV you could opt for the smaller 'stubby' or 'super stubby' version of my undertray. If you want the full FPV Dual batt kit you will want the FPV custom undertray, dual battery cage and probably the filter housing if you have Fatshark Predator with the original filter (I am waiting for the newer filter so i can design a housing for it).
    All you'd then need is a paralel battery cable and the spacers to mount the tray to the phantom (specific details/video can be found here: viewtopic.php?f=9&t=2082)

    I found no problem at all with the CG.
    When using the Hero3 this didn't surprise me as its weight counters that of the underslung battery but even without the Hero the CG was fine. I found this to be true in GPS and ATTI mode (I have yet to dare testing it in manual!). I am pretty sure this is largely due to the Naza.
    Put it this way - that photo was taken by literally hovering above me, putting the TX down, picking the camera up and snapping away and it stayed nice and still for me.

    I will try and rope in someone that is capable of using my camera to film a full test soon (proof is in the watching afterall!). :cool:
     
  5. martcerv

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    Do you know your total weight on that flight, I may be blind if you posted it but I couldnt see it. I just did some FPV 3d test flights using 2 hero3 blacks and my 2700mah battery getting 9 min but thats landing on red LED didnt check voltages though I have them still on default levels. My total weight these tests was 1275g which is easily the heaviest I have flow and would likely be more then your dual batt setup as my 2 cams anti jello mount and filters all up are 405g.

    Im thinking of getting a lower shell off a Phantom vision when thats released and just go for some good light high capacity batteries in that. I think this would have to be the ultimate Phantom batter, needs new plugs but 4500mah @278g 3s is insane. I so hope this can fit into the vision shell or maybe I will just mount one externally on the regular phantom somehow.

    [​IMG]

     
  6. rilot

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    Is the Vision going to have a larger battery bay?

    I'm going to start testing my own dual-battery setup tomorrow. I've got a bunch of different props to try but my calculations indicate that 9x5 Graupners or Tri-Blade 9x5s will give me enough lift.
     
  7. DeweyAXD

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    You are not going blind martcerv I forgot to put the total weight on that flight (have just put an edit in). It was 1134 grams. The Hero is 75 grams if i recall + my frame'ish (4g) and a slightly heavier FPV cable would be about 1220 (although that would include the Fatshark cam/mount too which wouldn't be needed).

    That battery is crazy! 4500mah 3s at that weight? Seems almost too good to be true! Sadly I doubt that will fit the Vision even with its larger beer belly (rilot - yep it is due to have a bigger *** for a larger batt but no dimensions issued yet as far as I've seen).
    150mm long compared to my (big) Nanotech 105mm and it is a wideboy too at 44mm compared to 34mm. I'd suggest making a cage for it on the underside but not sure if you could fit that and 2 hero3's. Would love to see a pic of the 3D rig (your dual bat rig too Rilot).
     
  8. rilot

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    I'll get some pics up tomorrow if I can.
    It's looking like quite a beast with the brushless gimbal slung underneath and the batteries stuck on the sides.
     
  9. martcerv

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    Here is the current Carbon Fiber, 3M Dual lock tape, Cardboard, anti jello mount and electrical tape setup :lol:

    This is more for function, keep cameras aligned and stiff as a pair but isolate vibration to them both to get jello free video. Here I also tested a couple ND filters whilst also testing the 3d setup, its not pretty but it works and the triblades make it fly nice even at this weight. Good stress test on the frame as I am gunning it around FPV style with this setup, 3D is working very well just some software issues trying to sync it. I may need another 3rd party plugin as unfortunately cineform free or even pro cant re-sync hero3 black footage.

    [​IMG]

    [​IMG]

    The filter test showed one was much better then the other but I misjudged the light stops of each so it wasn't the most conclusive test. I will try and pair up some more even filters for next time to see a better comparison of these.
     
  10. rilot

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    Those props; GWS 9x5s?
     
  11. martcerv

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    Yes thats the ones, anyone with a heavy phantom should give these a go. Pretty cheap and if you balance them properly can give jello free video.. Even though there is more prop with regular flying it gives longer run times as its not fighting just to stay in the air, I tried graupner clone carbons a while back and at 8 inch they were horrible, the profile really doesnt suit a phantom even at 9 inch they barely get as much lift as stock DJI 8 inch props. With the 9050x3 hovering is much lower throttle percentage in manual mode so much more lift and so regular flying in ATTI or GPS holding altitude will use much lower RPM. 8040x3 were a big fail very unstable very high RPM but these props I am using are easily my favourites atm.
     
  12. Glockindahaus

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    Do they fit the Phantom without any changes to the center of the prop?
     
  13. Glockindahaus

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    That is pretty amazing. 15+ minutes with that rig??? Wow. I've been pretty hesitant to even try more then 10 minutes with my dual rig which is pretty similar to yours - even a bit lighter.. Your batteries had to be almost nearly depleted though, right?
     
  14. rilot

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    I have just bought 4 of those so will be trying them this weekend.

    I don't rate the Graupners on the Phantom at all. I have a set of 8 x 5s and it flies really unstable with them on. I tried playing with the gains but I put it down to the profile in the end. Not enough lift.

    Recently I dropped the Graupner 9x5s on my F550 and replaced them with APC Electric E 9x4.5s and it's much more stable.

    I'll stick all my Graupners on Ebay I think. Expensive props and not that great.
     
  15. DeweyAXD

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    Both had a good amount of kick in them still. The thing that was interesting was that the NanoTech got down to 11.18v whereas the stock 2200 was still at 11.3v so clearly not even draining - What I don't know is how the power usage is managed across 2 batteries with differing capacity. I assume because the NanoTech is a slightly bet C rating it drains first/fast leaving more juice in the stock battery.

    After landing/shutoff the lights where flashing green which makes sense as there is potentially another minute or so safe flying time. It is suggested never to take individual cells down below 3.3v per cell (some say 3.2v) and all were around the 3.7 mark. Given that they start at 4.2v per cell there is plenty left.

    Stock 1st level voltage protection is set at:
    11.3v No Load - 10.70v loaded
    Stock 2nd level voltage protection is set at:
    11.2v No Load - 10.60v loaded

    My only worry is that there is no way of managing which battery drains. Really I'd want the Phantom to stop using power out of the first battery that hits 10.7v under load and then take the remaining juice from the other batt... in practice this would need a programable board to manage it. Doable with say an Arduino board but a lot of work and more weight to add too!
     
  16. Glockindahaus

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    Or simply use the exact same batteries in the configuration.
     
  17. DeweyAXD

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    :lol: yes that isn't a bad shout. I'll make a cage for the NanoTechs this weekend i think.
     
  18. rilot

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    The difference in drain is due to the internal resistance of the cells rather than the C rating. This is why expensive batteries have matched cell impedance.
    I expect the Turnigy Nano-Tech batteries have a lower internal resistance.

    I run dual Nano-Tech batteries on my F550 and they drain equally. I wouldn't ever wire up different makes of battery in parallel.
     
  19. Glockindahaus

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    YES PLEASE! I'll be one of your first customers!
     
  20. DeweyAXD

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    Yeah I wasn't sure about mixing but I don't see it can do any harm to the Phantom itself. It will only draw what it needs from the parallel circuit. I just need to make sure one batt doesn't fall lower than then safe limit while the second one is used.

    :D should be ready to purchase by Monday if not before... it'll have a beefier pin and a less fiddly method to fix on (all going well!)