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Car Alternator as Human Powered Generator

Discussion in 'Electronic Basics' started by Robin, May 29, 2004.

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  1. Robin

    Robin Guest

    Hello All,

    I do some volunteer work that provides rural villagers in Nepal with
    WiFi communication (See http://NepalWireless.net if you are
    interested). As part of this work, we need to develop a human powered
    generator to charge our solar batteries when there is no sun for
    months on end. Is a car alternator and a bicycle a possibility? How
    much current/voltage does a typical alternator produce and what RPM is
    necessary? These are both readily available in Nepal, so they would
    be idea. Thanks very much.

    Robin Shields
     
  2. Roger Gt

    Roger Gt Guest

    X-No-Archive: yes
    : Hello All,
    :
    : I do some volunteer work that provides rural villagers in
    Nepal with
    : WiFi communication (See http://NepalWireless.net if you are
    : interested). As part of this work, we need to develop a human
    powered
    : generator to charge our solar batteries when there is no sun for
    : months on end. Is a car alternator and a bicycle a possibility?
    How
    : much current/voltage does a typical alternator produce and what
    RPM is
    : necessary? These are both readily available in Nepal, so they
    would
    : be idea. Thanks very much.
    :
    : Robin Shields

    The Short answer is NO! Takes about one horse power and about
    2000 RPM... Not something most men can do for any length of time.

    Wind mill maybe?
     
  3.  
  4. Rich Grise

    Rich Grise Guest

    Do the experiment! :) Take a bike, and take the tire off the back
    wheel, and use it as a pulley. Run a belt around it and the generator
    /alternator pulley, and use an ordinary 12V battery/regulator. Then
    pump away! A man can easily generate 1 HP for awhile, and if you're
    in really good shape, you can pedal an airplane across the English
    Channel. :)

    In fact, I seem to remember doing an experiment in HS physics class,
    where they went to a 2-flight stairwell and had a couple of volunteer
    boys run up it as fast as they could. They timed it, and calculated
    the kinetic energy expended, and some guys made almost .75 hp. So I
    think any old ordinary person on a bike could make enough electricity
    to run a radio or something. In fact, in the Science Musem in St. Paul,
    MN, they used to (maybe still do) have setups exactly like that, with
    a TV right in front of you and I think meters.

    As to RPM, I really don't think it matters that much, as long
    as it's more than some threshold value. I can visualize a belt
    around a bike wheel driving a "standard" alternator, and I can
    almost hear it whirring. It just intuitively, to me, seems to
    "automatically" run at the right speed. And you can get 10- and
    more- speed bikes!

    Good Luck!
    Rich
     
  5. Bill

    Bill Guest

    How about animals and gears?

    Bill
     
  6. been there, done that. it will be a long uphill stretch of road to pedal
    though. For a rikshaw jock no problem.
    They run entire sound stages at alternative energy shows from banks of
    bicycles. Ganging up is definitely a plus.
    Put a rheostat on the field so you can adjust.
    put it in the hotel lobby so the fat tourists can work out some.
     
  7. Oxen or other animals going in a circle with a drive to the alternator.
     
  8. CWatters

    CWatters Guest

    This site may be of interest...
    http://ww2.green-trust.org:8383/2000/humanpower.htm

    Some info on using a car alternator here.
    http://www.lookout2000.com/windpower/

    The main problem is that you need 800 to 1000 rpm at least to drive a car
    alternator (Note gearing up in photo of the windmill on the page above). A
    human works best at <100rpm so you would need 10:1 gear up at least. Gearing
    up isn't very efficient.

    This web site (scroll down it)..

    http://homepages.enterprise.net/hugh0piggott/books/

    ...has plans showing how to make an alternator out of a brake drum and links
    to other interesting stuff.

    Colin
     
  9. Soeren

    Soeren Guest

    Hi Robin,

    I think you would be better off with generators with permanent magnets and
    of a smaller size (or even DC-motors in reverse?), like some slightly
    owergrown bicycle dynamos.


    --
    Regards,
    Soeren

    * If it puzzles you dear... Reverse engineer *
    New forum: <URL:http://www.ElektronikTeknolog.dk/cgi-bin/SPEED/>
     
  10. Jim Thompson

    Jim Thompson Guest

    Absolutely! I worked on the electronics for an exercise bicycle that
    used an alternator as a variable physical load AND provided the power
    for the circuits.

    ...Jim Thompson
     
  11. Bob

    Bob Guest


    Very interesting. It looks like the answer to Robin's question is yes.

    Bob
     
  12. Hasn't Lee Felsenstein (of Homebrew Computer Club fame) already done
    this for a village in Laos? Perhaps you can contact him, or any number
    of folks who worked on this

    http://www.usatoday.com/tech/news/2003-02-12-net-pedaling_x.htm

    Alternately, you could contact Jon Katz, who has set up homebrew hydro
    power generation in the Domican Republic using a three phase motor, a
    controller, and some space heaters:

    http://www.cnn.com/SPECIALS/2000/virtualvillages/story/dom.rep/interviews/

    I suspect you can contact Jon at his Cornell email address for more
    information.

    Anyway, good luck with your project.

    Regards,
    Bob Monsen
     
  13. Roger Gt

    Roger Gt Guest

    X-No-Archive: yes
    "Bill" wrote
    : "Roger Gt" wrote
    : > "Robin" wrote

    : > : Hello All,
    : > :
    : > : I do some volunteer work that provides rural
    : > : villagers in Nepal with WiFi communication
    : > : (See http://NepalWireless.net if you are
    : > : interested). As part of this work, we need
    : > : to develop a human powered generator to charge
    : > : our solar batteries when there is no sun for
    : > : months on end. Is a car alternator and a
    : > : bicycle a possibility? How much current/voltage
    : > : does a typical alternator produce and what RPM is
    : > : necessary? These are both readily available
    : > : in Nepal, so they would be idea. Thanks very much.
    : > : Robin Shields
    : >
    : > The Short answer is NO! Takes about one horse power and about
    : > 2000 RPM... Not something most men can do for any length of
    time.
    : >
    : > Wind mill maybe?
    : >
    : How about animals and gears? Bill

    Messy, But an Ox on a "go around" pulling an arm could be geared
    up to do it. Someone would need to clean up after the ox though!
    That would require an attendant to care for the ox.
    The typical alternator from a small car or pickup will produce up
    to about 50 amperes at full rpm, but it also draws power from the
    battery for the field current. So disconnect it when not in use!

    The gear ratio is really big. Lets see, an Ox walking around once
    ever 15 seconds, to get 2000 rpm. Gear up is 8000/1. It's doable
    but messy.

    1. First you need a 6 foot diameter pulley mounted on the center
    of the "go-Around" ( Nominal 4RPM) a belt drives a 2 inch pulley
    gets you a 36/1 ratio to provide (144RPM), then the 2 inch pulley
    shaft drives a 30 inch pulley, this belt drives a 2 inch pulley on
    the alternator at 2150RPM. Gee, only two stages!

    I'll leave the simple mechanics up to your available materials....
    and ingenuity!

    If the oz moves slower you need more gear up! A 36 inch secondary
    pulley will allow the Ox to go around in 20 seconds! (3RPM)

    Gee, why do villagers need Wifi? Can't they just talk to each
    other? My fathers farm doesn't have Wifi. No one misses it! The
    Cows least of all! They just kick a soccer ball around the
    pasture for entertainment!
     
  14. Mark (UK)

    Mark (UK) Guest

    Hi!

    Could you not just put the Ox in a field to graze, stick a pipe up it's
    rear, collect the methane, then use that to drive an engine, or burn it
    to generate steam to power a turbine to run the alternator!

    I'm not too sure of the Cubic meters per hour one average size Ox
    produces tho.....

    :)

    Yours, Mark.
     
  15. Roger Gt

    Roger Gt Guest

    X-No-Archive: yes
    A prime example of true British Thinking!
    Cubic meters? How about cubic "cubits?"
    I'll let you insert the tube!
    (Top posted in response to a TOP POSTER!)

    "Mark (UK)" wrote
    : Hi!
    : Could you not just put the Ox in a field to graze, stick a pipe
    up it's
    : rear, collect the methane, then use that to drive an engine, or
    burn it
    : to generate steam to power a turbine to run the alternator!
    :
    : I'm not too sure of the Cubic meters per hour one average size
    Ox
    : produces tho.....
    : :)
    : Yours, Mark.

    <snip>
    : > : How about animals and gears? Bill
    : >
    : > Messy, But an Ox on a "go around" pulling an arm could be
    geared
    : > up to do it. Someone would need to clean up after the ox
    though!
    : > That would require an attendant to care for the ox.
    : > The typical alternator from a small car or pickup will produce
    up
    : > to about 50 amperes at full rpm, but it also draws power from
    the
    : > battery for the field current. So disconnect it when not in
    use!
    : >
    : > The gear ratio is really big. Lets see, an Ox walking around
    once
    : > ever 15 seconds, to get 2000 rpm. Gear up is 8000/1. It's
    doable
    : > but messy.
    : >
    : > 1. First you need a 6 foot diameter pulley mounted on the
    center
    : > of the "go-Around" ( Nominal 4RPM) a belt drives a 2 inch
    pulley
    : > gets you a 36/1 ratio to provide (144RPM), then the 2 inch
    pulley
    : > shaft drives a 30 inch pulley, this belt drives a 2 inch
    pulley on
    : > the alternator at 2150RPM. Gee, only two stages!
    : >
    : > I'll leave the simple mechanics up to your available
    materials....
    : > and ingenuity!
    : >
    : > If the oz moves slower you need more gear up! A 36 inch
    secondary
    : > pulley will allow the Ox to go around in 20 seconds! (3RPM)
    : >
    : > Gee, why do villagers need Wifi? Can't they just talk to each
    : > other? My fathers farm doesn't have Wifi. No one misses it!
    The
    : > Cows least of all! They just kick a soccer ball around the
    : > pasture for entertainment!
    : >
    : >
    : >
    : >
    :
     
  16. Rich.Andrews

    Rich.Andrews Guest

    (Robin) wrote in
    It takes a fair amount of power to run an alternator at full output. If
    you take a 50 amp alternator, ground the output and fully energize the
    rotor coil, ir will stall out a large 6 cylinder Cummins diesel engine.
    As a matter of fact it will stall it out so quickly, that a bystander
    would say that you shut the engine off.

    r
     
  17. mike

    mike Guest

    Don't they have wind in that part of the world?
    If you must pedal, I'd think about a lower RPM generator so you don't
    use up all the energy overcoming mechanical losses.
    mike

    --
    Return address is VALID.
    Bunch of stuff For Sale and Wanted at the link below.
    Toshiba & Compaq LiIon Batteries, Test Equipment
    Yaesu FTV901R Transverter, 30pS pulser
    Tektronix Concept Books, spot welding head...
    http://www.geocities.com/SiliconValley/Monitor/4710/
     
  18. JeffM

    JeffM Guest

    Absolutely! I worked on the electronics for an exercise bicycle that
    Now mention that it requires a battery in good shape
    (or a live electrical outlet) to boot it.
    An old '50s style PM automotive generator
    doesn't need an electrical source for its field.
     
  19. Jim Thompson

    Jim Thompson Guest

    Where in the world did you get that idea? Must be some weenie engine!

    12V at 50A is only 600W, even presuming something like 50% efficiency
    that's only 1.6hp.

    IIRC a typical automotive 50A alternator takes about 6hp input at
    (alternator) 14,000RPM.

    ...Jim Thompson
     
  20. Jim Thompson

    Jim Thompson Guest

    A GM alternator doesn't either, to get it started, then it requires a
    minimum load, or it goes over-voltage. GM calls that load "daylight
    headlights" ;-)

    ...Jim Thompson
     
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