Project: Elliptical energy recovery

Discussion in 'The Projects Forum' started by LeonhardKoopaEuler, Apr 1, 2011.

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  1. LeonhardKoopaEuler

    Thread Starter New Member

    Apr 1, 2011
    I'm trying to get the power out of an elliptical, but have run into a few problems.
    I plan on passing a variable DC voltage through either a DC/DC converter or off-grid charger to a 12 volt battery and then to a DC/AC inverter to finally get AC power I can use to run a tv.
    First off, is it better to use a DC/DC converter or an off gird inverter? Or are they both the same thing? Also, how should I size that piece of equipment. An electrician I know said that the DC/DC converter is an active load, so with the DC/DC converter, the battery and the tv on this one circuit, it would be hard to find out what the resistance would be of the whole circuit.
    How do I know what the resistance of an active load is so that I can buy the right one?

    If anyone could help me out with this problem or at least give some advice, I would really appreciate. I'll take any help I can get.
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    Definitions of elliptical on the Web:

    * egg-shaped: rounded like an egg
    * elliptic: characterized by extreme economy of expression or omission of superfluous elements; "the dialogue is elliptic and full of dark hints"; "the explanation was concise, even elliptical to the verge of obscurity"- H.O.Taylor

    * In geometry, an ellipse (from Greek ἔλλειψις elleipsis, a "falling short") is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is perpendicular to the axis. ...

    * An elliptical galaxy; An elliptical trainer; In a shape reminding of an ellipse; oval; Of, or showing ellipsis; having a word or words omitted; Concise, condensed; Alternative form of elliptic

    * Ellipticism - Elliptical Poetry or ellipticism is a literary-critical term introduced by critic Stephen Burt in a 1998 essay in Boston Review on Susan Wheeler, and expanded upon in an eponymous essay in American Letters & Commentary. ...

    * an oblique circle

    * Refers to a class of canopies with a tapered or approximately elliptical planform.

    * A stone shape whose perimeter is an ellipse. Top of Page

    * type of perforation; aka. syncopated.

    * A door or window having a top rail with an egg-shaped radius, ending in a rounded point at its apex.

    * Having the outline of an ellipse, broadest at middle and narrower at each end.

    * Oval shaped.

    * from 3 to 4 times as long as wide, tapering equally from the center toward both ends.

    * elongate-oval; differs from oval by having the lines nearly parallel in the middle.

    * A geometric shape, the finite or bounded case of a conic section, or a machine used to improve cardiovascular fitness.
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    As the above post hints, it would be really useful to have a definition of "an elliptical".
  4. Adjuster

    Well-Known Member

    Dec 26, 2010
    Very likely a training machine, I would think. This idea seems to be doing the rounds:

    Edit: A rough calculation, assuming 150W output and £0.13 per kWh suggests a return of £0.02 per hour, ignoring the initial and maintenance costs of the generator.
    Last edited: Apr 2, 2011
  5. wayneh


    Sep 9, 2010
    You need to specify how much power, and in what form (voltage, AC vs. DC, wattage, etc.) your TV requires. For one thing, if the TV needs more than about 50W, forget it. Most folks can't generate more than about 100W for very long, and there will be losses.

    Depending how ambitious you are, you might be able to tell if the TV internally converts the AC supply to DC. Bypassing the transformer and rectifier to deliver the TV what it really uses could increase your end-to-end efficiency.
  6. Papabravo


    Feb 24, 2006
    There is a demonstration at the hands-on museum of a hand-cranked AC generator with 3 20W bulbs wired in parallel with individual toggle switches. With no load it is easy to turn the hand crank given the gearing. Flip the first switch and it becomes apparent that the mechanical equivalent of 20 Watts is significant. Flip the second switch and it takes some real effort to continue. Flip the third switch for 60 Watts and most people make about another turn and a half.
  7. wayneh


    Sep 9, 2010
    The Lance Armstrongs of the world can generate 300W or so for bursts. That's almost 1/2HP. But those guys can go faster UP a hill than I can go DOWN the hill.
  8. Wendy


    Mar 24, 2008
  9. Ron H

    AAC Fanatic!

    Apr 14, 2005
    Sounds like an April Fools joke to me.
  10. nsaspook

    AAC Fanatic!

    Aug 27, 2009
  11. PackratKing

    Well-Known Member

    Jul 13, 2008
    Well <golly gee>.......if you are pedalling your elliptic, watching a teevee, and some starlet begins to strip, you would be amazed how hard one can pedal to keep from losing the picture !!! :D:D just can't feed straight lines to a wannabe comedian !! you'll get zinged every time :rolleyes:

    [ subject to deletion ]
    Last edited by a moderator: Apr 4, 2011
  12. beenthere

    Retired Moderator

    Apr 20, 2004
    Given -
    - and the absence of the OP, this thread is not going anywhere.
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