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Phantom Holes

Discussion in 'General Discussion' started by thiagottjv, Jan 8, 2014.

  1. thiagottjv

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    Hi guys,

    I'm not with my phantom yet, but I really need to know some measures.
    I`ll make a baseplate (to hold a battery for the gimbal and the Fatshark TX) for my Phantom like this one:

    [​IMG]


    And I'm needing the measures X, Y and Z like on this picture:

    [​IMG]

    Could you guys help me? This will really help!

    Thanks. :D
     
  2. Gizmo3000

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    I'll give you some advice: don't bother.
    gimbals and FPV don't suck up too much energy,. at most they're sapping 10% of your flight time, (and that's being generous).
    But adding an extra battery to power them,. while saving more main battery power, will also force the main battery to compensate for the extra weight.
    Instead of gaining flight time, you'll lose even more flight time! (for every gram you add, you lose about 1 second).
    plus your Phantom will weight a bit more.

    on top to that, adding that baseplate idea will add even more weight
    and if you're attaching a gimbal to it, that will then lower the gimbal too far
    ..and then you'd have to add leg extensions,. which also adds more weight! :eek:
     
  3. thiagottjv

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    Gizmo, thanks for your reply!

    But how about the transmitter power? They combined wont suck all the battery?
    I was thinking of using a 1450mah or 800mah to power the transmitter and the Tarot gimbal.

    Thanks.
     
  4. OI Photography

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    You could just buy the one you're trying to replicate: https://www.shapeways.com/model/1174284 ... terialId=6

    It's extremely thin and lightweight. but works just as intended. If you're mounting an FPV Tx it's a great way to do it...it doesn't allow you to mount most Gimbals as it is, but there is a version engineered to work with the Zenmuse.

    Gizmo is right, it's usually counter-productive to mount even a small separate batt for the gimbal/FPV, they weight it would add negates any benefit from the miniscule amount of flight time gained by not powering them off the main batt.
     
  5. thiagottjv

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    Ok then, I think I`ll make it simple. Use the battery to power everything. And use a velcro-tape to secure the TX.
    Thanks for your help, guys.
     
  6. Gizmo3000

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    the combined power draw of FPV Tx and Gimbal are minimal compared to the draw that the motors have to use to keep the 1200g craft in the air.

    Just solder two male JST's to your Aux power and use those plugs to power both.

    The key to longer flights is to keep things as light as possible and not haul about any more weight than you have to.

    If you're going to add another battery, you'll gain more flight time by adding it in parallel to the main battery, that way you'd be using all it's available stored energy for flying in a single flight.

    Maybe sometime tonight I'll run a test to see how much energy my FPV+Gimal use up in a given timeframe, but imagine it's not very much.
     
  7. Gizmo3000

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    yes,. get the high strength velcro and you'll be fine that's what I use.
    it's nearly impossible to pull the tape off once it's adhered to the shell.
     
  8. Gizmo3000

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    So I had a couple minutes and gave it a shot.. not a perfectly controlled test, but a good ballpark idea of how much juice is used by gimbal and FPV.

    I inserted a freshly charged battery into my Phantom running a 250mw fathshark Tx, powering my Tarot gimbal, as well as sending juice to charge my GoPro. I waited perhaps 15-20 seconds to give my gimbal time to boot up and then I set the timer to 2 minutes.
    - and then I picked up the Phantom and pretended to fly it around my living room in turbulent conditions (rolling it back and forth and front and back to use both motors to stabilize.)
    then removed the battery when the timer ran out.

    I tested my battery prior to flying on a stand alone tester.
    in the two minutes it went from 4.18 on each cell to 4.13 a cell.
    when I then stuck it back on my charger and hit it with a balance charge, total amount to recharge was = 70 mah!

    I get about 6-7 minutes of flying out of my 2200mah battery, requiring about 1800mah to recharge..
    so being very generous, the gimbal and FPV are eating up 245mah per flight. (13.6%, a bit higher than I thought it would be).
    14% of 7 minutes comes to .95 minute., so that's how much more flight time I'd get if I turned off the gimbals and stuff.

    So to actually benefit from using an external battery, I'd need one that weight considerably less than 60g, (because every added g = 1 second of lost flight. a 60g battery would only break even in flight time.
    tho yes, there appears to be a few 350mah batteries that weigh 32-39g. So theoretically, I could fly an extra 21-28 seconds using one of those batteries. (mounted with tape or velcro, as any additional hardware would add more weight as well).

    But then that would also require me to buy enough of those batteries to use for each and every flight , and would have to be installed prior to every flight. (where I'd want maximum flight time). and charged before flights as well.
    Kind've a hassle for such a small benefit.

    a much better investment would be to merely put the money towards higher Mah main batteries, like the Zippy 2800.
     
  9. thiagottjv

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    Wow, thanks for the test!

    So... it really consume more because of the weight then because of the power.
    If a normal phantom would fly 12~15 min and you're getting 6~7 then the weight + the power consumption is the half of the battery life.
    If the consumed mah is 1800, then 900 is for the two. 650mah is just for the weight!

    So... the key is keep it light! :shock:

    Thanks again.
     
  10. ElGuano

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    If you're looking to maximize flight time and optimize your mods, you've just hit on the most important epiphany you'll ever make in this hobby. Weight is the enemy, pure and simple. Everything gram you add has a cost, no matter how insignificant it seems, and every gram you save has a complementary benefit.
     
  11. Pull_Up

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    (C) Lotus Cars since 1948 ;)