One Battery or Two?

Discussion in 'Cinestar Misc' started by Andrew Goodwin, Sep 25, 2012.

  1. Andrew Goodwin

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    In your opinion, is it better to fly a single battery, or two in parallel?

    Is it too much work for a single battery? Just a matter of flight times?
     
  2. Tabb Firchau

    Tabb Firchau Administrator
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    HI Andrew, on high value ships I fly 2 batteries in parallel, for lower dollar stuff I will fly 1 battery.

    2 can be a pain to charge but offer better redundancy.
     
  3. Morgan Friedland

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    What do you mean by ships? Did you mean to say shoots? (I ask because I have not seen a low dollar ship yet.
     
  4. Tabb Firchau

    Tabb Firchau Administrator
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    Hi Morgan, I meant multi rotors when I said ships. All I meant is I treat a CineStar 6 with a GH2 a little differently then I treat one with an EPIC onboard. I was referring to the $ value of the total package.
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    "Ships" is a traditional reference to "airships" -- which is not just dirigibles. So Cinestars get called ships, aircrafts, and/or birds. ;)
    And no, to those English forum readers, not those kinds of birds. :rolleyes:

    Even today, if you get insurance for everything from a 747 down to a sailplane, it's called "hull" insurance.

    Andy.
     
  6. SteveWilson

    SteveWilson Member

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    Tabb and anyone else, have you seen a four battery set-up on a CineStar8? I wanted to get your thoughts on the best way to mount the batteries. Our flying is all about endurance. Previously I had two batteries on the battery tray and two down below on the AV130. I've now switched over to the 2-axis CS gimbal so I need to relocate two batteries. Any suggestions where to mount them to keep her balanced? I don't want to reinvent the wheel if others have already come up with a solution. We are using a pretty light Panasonic - 320 grams so not a ton of weight way down below that needs counterbalancing.

    Thanks.
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I pretty sure I've seen a four battery setup out on the web where the batteries were arranged around the periphery of the upper Cinestar hub plate--basically snugged up against those four flat heat-sink plates on the power distribution board.

    Sadly, I cannot remember where I saw that image though....if I find it (or recall where I saw it), I'll post the image.

    Andy.
     
  8. SteveWilson

    SteveWilson Member

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    Thanks Andy, that makes a lot of sense.
     
  9. Tabb Firchau

    Tabb Firchau Administrator
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    Hi Steve, Depending on the size / shape of your packs I usually just stack them on the battery plate. This is usually only with big cameras underneath though so if this may make the vertical CG on the rig too high if you are flying a light camera.

    How big are the packs you are using? Even a 2x 9000 Mah Setup should give killer flight times!

    Tabb
     
  10. SteveWilson

    SteveWilson Member

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    We have a variety of packs. The first couple years we flew Mikrokopter Okto2's so we bought batteries to work with them. All 4s. The vast majority are Hyperion 5000 and 6500s, a half dozen each of MaxAmps 6500 and Hyperion 5500, and now a couple QuadroPower 6200.

    I think I'll try and just strap them to the plate and have a look at the CG in MKtools and if need be, go to Andy's idea of the circle.

    Thanks for the input.
     
  11. Arthur Vieira

    Arthur Vieira Flight Squad

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    The 4 Pack Cinestar photo is right here on the Forum - second picture.
    http://forum.freeflysystems.com/index.php?threads/pictures-of-your-bird.13/
    I'll go with Tabb idea of putting all the pack on the battery plate if possible. In theory (I haven't tried this.... yet) staking all the batteries in the same place, in the center, will elevate the Center of Gravity of the CS thus compensating for a heavy camera and by doing this - IN THEORY - reducing the pendulum effect during flight. In other hand... installing the packs around will make a slower and smother machine, but also will increase the inertia on the Pan, Tilt and Roll.
    There's a good and bad side on both, it's up to the pilot to decide.
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Thanks, Arthur. I knew I'd seen it recently.
    Steve: Are you planning to put all four packs in parallel? Just curious how you charge them up and ensure there's no voltage mismatch?
    I was planning on charging just pairs of QC6200's on the Hyperion 720i SuperDuo -- it can then balance the two batteries.

    Andy.
     
  13. Nick Kolias

    Nick Kolias Moderator
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    Interesting. I can certainly understand the appeal of longer flight times but, man, what a logistical headache managing four packs per hop. You can make a pretty solid case for using two large capacity packs instead. With these 8 to 12Ah packs out there now it's opening up all sorts of possibilities.

    nick
     
  14. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Which 12AH packs have you seen, Nick? My experiences with the Maxamps 11000 revealed that its max discharge rate of 40C caused voltage sags and flight times no longer than the higher C-rated QC6200.

    Thanks
    Andy.
     
  15. Nick Kolias

    Nick Kolias Moderator
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    Andy, somewhere I've seen 12,000mAh packs advertised. Let me sift through my emails to find it.

    That's pretty disheartening to hear you had such poor results from the big Maxamps packs. I would have thought 40C should be sufficient for pretty good performance on our multi-rotors. How many of those packs did you run through the ringer?

    nick
     
  16. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I would have thought 40C (which, in this case is 40 x 11, 440 Amps max discharge rate) would have been more than enough. As I said in another posting, 440 Amps is higher than the QC6200 -- which sports a 25C/50C burst, so that would be 50 x 6.2, or 310 Amps.

    I've only got one 11000 pack here and I've not been able to fly it more than once (so, yeah, a sample size of one is not good). I'll see if I can get out to later today with it and report back.

    Andy.
     
  17. Tabb Firchau

    Tabb Firchau Administrator
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    Andy,

    That 11000 pack really should not be sagging that much under load. WIth such a big capacity it should barely be stressed flying your CineStar 8. Do they publish discharge curves for the Maxamps?

    Tabb
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    That's what I thought, Tabb. I've not seen discharge curves and, since I mentioned the possibility of needing to return the $300 Maxamps battery, Clint's gone quiet -- it could, of course, be that he's out of town or off sick. I just received a second Maxamps 11000 I'd ordered, so I might open the box and try a parallel arrangement to prove the point. Hope it's not a $600 mistake! :(

    I'm also fretting that "True 40C" as advertised isn't actually 40C, or it's 40C but significant voltage sag.
    If only the wind would die down I could go fly -- gorgeous weather but nuclear winds coming through the Columbia Gorge I think...or maybe coming down the Columbia River from the coast. Frustrating. I need to find an indoor hall in which I can do still air test flying....

    Andy.
     
  19. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Just for the record, Clint's out of the office -- so let me correct any impression that I might have created by implying that he was being unresponsive.

    Andy
     
  20. Josh Lambeth

    Josh Lambeth Well-Known Member

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    I am hoping to go fly mine tonight... wonder if I will get the same results...

    Josh
     

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