Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

DJI + Batterylife FPV Range, problems.

Discussion in 'General Discussion' started by Alveprinsen, Jun 16, 2013.

  1. Alveprinsen

    Joined:
    Jun 16, 2013
    Messages:
    7
    Likes Received:
    0
    Ok, so this is my DJI Phantom. That is, without the carbon fiber utility tray and extra battery mounted underneath:
    [​IMG]

    The specs are as following:

    1x DJI Phantom
    1x set of balanced Carbon fiber props
    1x Carbon fiber Utility mount
    1x QuadFrame Gimbal
    1x ImmersionRC 5.8GHz 600mW Video TX
    2x 2200mah batteries, one inside fuselage, one underneath mounted to utility mount.
    1x set of ImmersionRC Spironet antenna 5.8ghz
    1x FatShark Predator V2 goggles w. standard camera.
    1x Futaba T8J Controller w. transmitter.

    Total weight including two 2200mah batteries: 1350 grams.

    My questions:
    1. I get about 6 minutes of flight time. If I exceed this, it will come crashing down. Does this sound about right to you guys? 6 min flight time I mean for a 1350 gram DJI on 4400mah power?

    2. Max range with standard 250mW Video TX was 730m in open air. With my new 600mW Video TX, the range is extended by one a mere 50 meters. Logically, the range ought to have been doubled. Is this because I am not using an external receiver for my FatShark goggles, and just using the built-in one? Is the built-in video receiver in the FatShark Predator V2 simply too weak, even though the video TX on the Phantom is strong?

    Appreciating any input.
    Sincerely, Alveprinsen.
     
  2. auck

    Joined:
    Feb 20, 2013
    Messages:
    275
    Likes Received:
    0
    Location:
    San Jose, CA
    your flight time is about right. DJI states not to over load your phantom "Do not over load the multi-rotor(should be less than 1200g)". it has been shown that people who are close to or are over the weight limit has their flight time significantly reduced. simply put, the heavier the craft, the more power the craft uses to keep itself aloft. i would deduce that you are extremely close to the point where flight time vs weight is flat lined by weight before weight totally kills flight time altogether.
     
  3. Alveprinsen

    Joined:
    Jun 16, 2013
    Messages:
    7
    Likes Received:
    0
    Thank you very much for that information Sir. I wonder if loading another 2200mah battery would increase flight time, or simply result in the added weight nullifying the extra power and decreasing flight time even further...

    It would appear I need another drone. This one will have to do for now though. I guess I will just have to bring more batteries. :)

    If anyone has any idea about the 250mW vs. 600mW Video TX being equal in range though, I'd love to hear about it.

    Sincerely, Alveprinsen.
     
  4. Audaciter

    Joined:
    Mar 18, 2013
    Messages:
    724
    Likes Received:
    2
    Location:
    Sunnyvale, California, USA
    Auck, He is using 2 batteries, and only getting 6 minutes ? I think there is something wrong with that.
    My Phantom weighed 1250 g, and I was getting that much time with 1 battery.

    You may want to try 9" cf props, for more lift, but you should definitely be getting more time using 2 batteries.

    You must be getting RFI noise from something to limit the range that much. Is the transmitter located inside the Phantom ?
     
  5. DeweyAXD

    Joined:
    May 31, 2013
    Messages:
    818
    Likes Received:
    9
    Location:
    Oxfordshire, UK
    From the tests that I have done with two batts so far I'd say 6 mins at 1350g is probably right (though I've only flown at 1250g myself).
    The ratio between weight and Batt Mah is by no means conjoined because the motors and props that generate the lift have a static maximum output where as weight and batt Mah can be as much as you want (doesn’t mean it'll fly!).

    In other words you could strap 10 batts to the Phantom but the motors will never spin the props fast enough in stock form to even consider moving the thing off the ground.
    I actually think that you 'might' get more flight time having 1 stock 2200 mah batt and one smaller, lighter 2s 1100 batt but as yet I can't prove that (not sure on the affect of tapping a 2s in parallel with a 3s but at 11.1v it should be ok).

    Bigger props will help lift as Audaciter suggests but higher surface area and greater width creates more centrifugal load on the motors and more load = more current required to get the lift. Not saying it won't help especially if they are rigid carbon but the gains might not be astronomical.

    Think of the reasons you'd want a larger quad... its just not physical payload capacity, its bigger, faster motors and props all run by bigger batts.

    Question really is what upgrades to the motors are possible on the Phantom, what extra weight such beefier motors have and if the internal electronics can support them (with the Naza M i'd imagine the answer is yes). Of course their limitations will be the physical diameter (whether they can fit in the shell) and if not then you are looking at a new frame anyway.

    I'm sure a person good with maths (not me!) could work this all out but for us hobbyists all we can do is trial and error and spend spend spend. With the Phantom Vision not yet out you might simply find it better to sell the Phantom with kit and put the money to a bigger unit because I fear chasing even 15 mins FPV time on a Phantom looks beyond the laws of physics (with stock motors).
     
  6. jumanoc

    Joined:
    Jan 21, 2013
    Messages:
    700
    Likes Received:
    8
    Just some points for better analyzing:
    1) How long time did you get with just 1 battery ?
    2) May be Gimbal is eating much juice ?
    3) Around immersion600 mW: How are your "standar antennas" oriented ? (better if TX antenna is parallel to RX)
     
  7. Alveprinsen

    Joined:
    Jun 16, 2013
    Messages:
    7
    Likes Received:
    0
    My Video transmitter is located as shown below:
    [​IMG]
     
  8. Alveprinsen

    Joined:
    Jun 16, 2013
    Messages:
    7
    Likes Received:
    0
    1. Havent tried with only one battery after adding all the weight. I guess I should, now that you mention it.
    2. Perhaps. Running tow Hyperion Atlas servos.
    3. I am using spironet antennas. Haven't tried the standard ones with the new transmitter. The transmitter antenna is oriented as shown in the picture in my post just above this one. :)
     
  9. Alveprinsen

    Joined:
    Jun 16, 2013
    Messages:
    7
    Likes Received:
    0
    My thoughts also, however; I need this unit to be small and portable. I got it all set up in its own carrying case. I will be taking it on a rather long expedition into the amazon in a few weeks. I wont be able to drag a bigass octo copter with me. :)
     
  10. DeweyAXD

    Joined:
    May 31, 2013
    Messages:
    818
    Likes Received:
    9
    Location:
    Oxfordshire, UK
    Nice work if you can get it I say! Make sure you post some footage on here when you go. I too like the 'idea' of a bigger unit but portability of the Phantom in i single case is sooo handy. Just allows you to get out there in a hurry. I'll be keeping mine for that reason (and probably end up buying a bigger one later!). Until then its just a case of finding a happy medium with battery life and looking at motor upgrades. Antigravity T-Motor MN2214-11 seem like a good option but I've not read enough real world tests yet to know if their 10% power 8% efficiency increase over stock do infact justify the costs (maybe others in here can comment?).

    I guess the only way to know is to buy some and test'em... tempting!
     
  11. Audaciter

    Joined:
    Mar 18, 2013
    Messages:
    724
    Likes Received:
    2
    Location:
    Sunnyvale, California, USA
    It looks like a clean installation. Have you tried disconnecting the gimbal servos, to see if they are a source of noise ?

    I see you are using spironet antenna's which should be getting you increased distance.

    Also, what kind of surroundings do you have when you fly ? Rural , industrial, urban ? lots of buildings, power wires etc ?

    Also, do you use a switching BEC for the servos, and another for the video transmitter ?

    You said you have a Futaba T8J radio. Do you use rechargeable 6.6v batteries for it, and have it selected as such in the
    radio programming ?
     
  12. ULI RAY

    Joined:
    Jan 16, 2013
    Messages:
    58
    Likes Received:
    1

    Attached Files:

  13. mercillus

    Joined:
    Apr 11, 2013
    Messages:
    158
    Likes Received:
    0
    Location:
    Leander, Texas USA
    All of your motors look to be newer than stock. Did you do the soldering?
     
  14. ULI RAY

    Joined:
    Jan 16, 2013
    Messages:
    58
    Likes Received:
    1
    yes that's DJI flame wheel motors, same as phantom but different color.
     
  15. koviatt

    Joined:
    May 21, 2013
    Messages:
    100
    Likes Received:
    16
    I have a similar set up and 2 2100 mAh packs. Spectrum receiver and telemetry. 250 mW video TX. Heavy dual axes gimbal. HeroPro 2 camera.

    We are consistently getting 9 - 12 minutes of medium duty flight. The added pack almost doubled our time. This was a pleasant surprise.

    I am using stock 8 inch props. I have sufficient climb out even towards he end of the flight.

    Kent
     
  16. Audaciter

    Joined:
    Mar 18, 2013
    Messages:
    724
    Likes Received:
    2
    Location:
    Sunnyvale, California, USA
    See, this is more what I was expecting. I couldn't believe 6 minutes with 1 battery. My old fossilized brain couldn't work
    with that kind of new math.
     
  17. Gizmo3000

    Joined:
    Jan 25, 2013
    Messages:
    1,859
    Likes Received:
    2
    Location:
    Sherman Oaks, CA
    Something isn't quite adding up I'd say.

    With that configuration you should be getting at least 6 minutes on a SINGLE battery
    ...and perhaps 8-9 with a dual battery (from what others have posted as results).

    definitely see how long it'll go on a single battery.

    Are they good name batteries that have been charged sufficiently?
     
  18. Audaciter

    Joined:
    Mar 18, 2013
    Messages:
    724
    Likes Received:
    2
    Location:
    Sunnyvale, California, USA
    I can tell you that the T-Motor MN2214-11 Anti Gravity motors are worth every penny.
     
  19. ULI RAY

    Joined:
    Jan 16, 2013
    Messages:
    58
    Likes Received:
    1
    is the gopro charging with the setup? this can cause a drain in the battery too ryt?
     
  20. lsbernal0

    Joined:
    Jun 23, 2013
    Messages:
    1
    Likes Received:
    0
    I live at 2.600 mts avobe the sea level and the air is thiner that the sea level air. That afect the battery flight life (more RPM and energy consuption of the stock motors) since day one to 6 to 7 min (no camera, no FPV and no gimbal). but whith the emax servo gimbal, hero3, 5.8Ghz 200Mwt fpv and 2 pahntom batterys makes the flyght joust 4 to 5 min. all the time I used 8´´ carbonprops.