Power requirements?

Discussion in 'Radian' started by Steve Maller, Dec 4, 2012.

  1. Steve Maller

    Steve Maller UAV Grief Counselor

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    I have a CS8 with 2-axis gimbal. I'm wondering if I should use a separate battery for the camera stuff or run it off the mains.

    With a separate battery powering the BEC, the 2 Radians (2-axis gimbal), HDMI converter, and an Iftron 5.8ghz FPV TX, what's a good guideline for how big of a battery i'll need? And/or if I power it from the copter's battery what kind of impact on flying times will I see?
     
  2. Adam Paugh

    Adam Paugh Distributor

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    Hello Steve,

    I think you will find that most people here are using a separate 12v Lipo to power the gimbal/downlink components. All of the components on your list above can be powered via 12v lipo with the BEC in-line to condition the voltage to 5.1v, less the 5.8gHz FPV Tx which should take 12v. This can be accomplished by splicing out the power from the 12v lipo and sending one wiring harness to the 5.8 Tx and the other wiring harness to the BEC. The BEC will then power the Radian, servos and FF hdmi converter.

    Hope this helps.

    Greetings,
    Adam
     
  3. Steve Maller

    Steve Maller UAV Grief Counselor

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    Adam, that's exactly what I was looking for.
    Is a 500mAh Lipo enough? 800? 1200?

    So grateful for this awesome resource! Thank you!
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Typically I've seen 1200 maH batteries, Steve. The one from QC has a nice form factor (so may others, but this is the one I use).
    I put a strip of Velcro in the middle of the label, and some camper foam tape to the top surface of the right hand forward boom (as you look at the gimbal from the rear), and some Velcro around the boom at battery. This puts the battery opposite the Radian sensor, servo and pulley for tilt and tends to counter balance it.

    I get over an hour's elapsed time on the battery -- I use a LiPo battery alarm on it so I don't forget to swap it out on a shoot.

    Andy.
     
  5. Jim Swanson

    Jim Swanson Member

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    Hey Andy,
    Adam mentioned a 12 volt lipo. Did he mean a 3s Lipo battery that is fully charged to 12.6?

    jim
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Jim:
    Firstly if it's not too much trouble, would you be kind enough to change your user name to your real first name and last name, please? The reasons for this (and how to do do it) are explained here: http://forum.freeflysystems.com/index.php?threads/real-names.497/

    Secondly, yeah....I think that's what Adam meant. I use a QC-1200 mAh.
    Thanks
    Andy
     
  7. Mark Melville

    Mark Melville Member

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    Andy I'm running a 7.4 2c 1900 lipo is that too little to run 3 radians and a stinger 250watt?
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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  9. Mark Melville

    Mark Melville Member

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    I saw that but just wondering if between the radians and video if the 7.4 2c is enough. Also my radians have just gone bonkers. I'll have to look into that issue tomorrow when I get back from set. Will the problems ever end. Don't answer.
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I think the real issue is not so much the Radians as the servos -- those servos can suck 1.5 Amps each when they're operating, but I presume you're powering them from another source. If you meant to say "Radians and servos," then it might be better to run them on a 3S 1200 mA LiPo. I get about an hour of continuous on time, with five flights in there before I swap out batteries.

    Andy.
     
  11. Mark Melville

    Mark Melville Member

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    I'm powering, servos, radians and the stinger from the 7.4 2c the bec is 6 amps. So I guess I'm under powered? I feel with project I take two steps forward and one back. I have a radian issue which I'll post under a separate thread.
     
  12. Steve Maller

    Steve Maller UAV Grief Counselor

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    I'd use a 3S battery, and make a 'Y' connector with a raw 12V (or so) lead going to the Stinger, and the other lead going to the BEC, which in turn feeds the Radians. I'm using 1200 mAH batteries, too.
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yeah, I hear you. You're on an asymptote to actually being finished with these copters.
    As the late Gilda Radner said (on Saturday Night Live), "It's always something."
    Or as a friend of mine said, "Before you can do anything, it seems like you have to something else...."

    Andy.
     
  14. Lauri Hakala

    Lauri Hakala Member

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    Hi guys! I'm using a 5v 3amp BEC for my three radians, freefly servos and freefly hdmi converter and started to worry the the 3amps is not enough. The battery is 1500mah 3s lipo and I use a y-harness for the 12v downlink. I don't know the exact power requirements of the freefly components so it's hard to calculate if my bec is underpowered. Would I be better of with a 5amp bec, just to be safe. Thanks!
     
  15. Jim Swanson

    Jim Swanson Member

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  16. Lauri Hakala

    Lauri Hakala Member

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    Thanks for the fast reply, will try that one!
     
  17. Colin

    Colin Member

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    Guys, watch that voltage going to the servos. Been there dont it and got the T shirt. 6v or less.
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The FF servo takes up to about 1.5 Amps when it's operating. So 4.5 Amps for a 3-Axis.

    Andy.
     
  19. Lauri Hakala

    Lauri Hakala Member

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    Thanks! One more question: how many mah's does the freefly hdmi-converter draw? I suppose it's something very minimal and I can just hook it up to one of my radian units under the same BEC.
     
  20. Gary Haynes

    Gary Haynes Administrator
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    HDMI is about 500 mah so hook it up. That's way a lot of people have done it to reduce wiring.
     

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