Advertise on Bikeforums.net



User Tag List

Results 1 to 18 of 18
  1. #1
    Member
    Join Date
    Aug 2006
    Location
    Central Texas
    My Bikes
    Rans Fusion,a bunch of goodwill bikes I work on
    Posts
    37
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Perpetual motion Ebike..:)

    Could someone more knowledgeable than me explain why it it not possible to run an ebike from a rear wheel motor and use a front wheel with a dynamo ,run it through a voltage regulator and run it back to charge the battery as you are moving down the road?

  2. #2
    Senior Member
    Join Date
    Aug 2008
    Posts
    536
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    the law of conservation of energy states that energy can not be create nor destroyed, it can only be changed from 1 kind of energy to another kind.

    with this in mind, you have to consider where your enery source is( your battery)....everytime you converts that energy into something else, there are inefficiencies associated to every conversion. the battery has internal resistance, the wires have internal resistance, the controller requires power just to operate, the motor is only 80% efficient at converting the energy to motion. each of thes processes produce heat. your battery power is lost due to this heat.

    then once the energy is mechanical energy, you have to consider the friction and rolling inefficiencies of your bearings,chain, wheels rolling on a less than smooth surface, even wind resistance.

    Bottom line, by the time your generator has produced electricity for your battery, it is only a fraction of the electricity required to move your bike forward.

    ........pause..............

    now if you consider that you are pedalling, too. then you are actually getting power from your muscles too. You might wonder if your muscles are capable of compensating for all the losses in your electric system, and it certainly can if you pedal hard enough and fast enough. But, in the real time, the losses from you electric system are greater than what you can provide from your muscles. Eventually, you need to stop the bike and plug it into the wall to recharge the battery.

  3. #3
    Senior Member
    Join Date
    Aug 2008
    Posts
    536
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    to rephrase, the generator does not create energy, it only converts it. it is not able to convert enough energy to recharge the battery because some of the energy was lost through inefficiencies.

  4. #4
    pedalphile
    Join Date
    Jul 2008
    Location
    ellington, ct
    My Bikes
    trek 1200, 520, Giant ATX 970, Raleigh Talon
    Posts
    1,027
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    don't listen to this conservation of energy propaganda put out by "big oil".

    you can do it. you just need the right gearing!!


  5. #5
    Banned.
    Join Date
    Jun 2008
    Posts
    40
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by trekker pete View Post
    don't listen to this conservation of energy propaganda put out by "big oil".

    you can do it. you just need the right gearing!!

    lol

  6. #6
    Super Moderator Allen's Avatar
    Join Date
    Sep 2005
    Location
    Atomic batteries to power; turbines to speed
    My Bikes
    Salsa La Raza, Panasonic Electric, Bria, Bamboo touring, Bamboo cargo
    Posts
    4,670
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by trekker pete View Post
    don't listen to this conservation of energy propaganda put out by "big oil".

    you can do it. you just need the right gearing!!

    I had no idea that Mayer and Einstein were oil men.

  7. #7
    Junior Member
    Join Date
    Jul 2008
    Posts
    21
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If you put a generator on the front wheel and a hub motor on back you will have created a pedalbike!!!!!! DO it..

    I saw a you tube video of this guy that had a sports car he converted to electric with fans mounted all over it to recharge the bateries as he drove lol, he actually got investors to pour money into it..

    I used to never be afraid of flying in a plane.. I thought if it were to crash I would just jump up at the last moment =P

  8. #8
    Senior Member 15rms's Avatar
    Join Date
    Oct 2007
    Posts
    263
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Trekker do it. If you did do it you would either be dead if it worked or looking tired because of all the peddling you would be doing to get the bike down the street.

  9. #9
    Senior Member
    Join Date
    Mar 2008
    Location
    Port Townsend, WA
    My Bikes
    xtracycle, electric recumbent, downtube folder and more
    Posts
    983
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It would be easier to pedal if you also install anti-gravity discs too.

  10. #10
    Senior Member misslexi's Avatar
    Join Date
    Aug 2008
    Posts
    218
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    This can work, just put a really large wheel on the rear and a real small one on the front. This way you're always going downhill <g>

  11. #11
    Member
    Join Date
    Aug 2006
    Location
    Central Texas
    My Bikes
    Rans Fusion,a bunch of goodwill bikes I work on
    Posts
    37
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I knew this would be a fun thread.

  12. #12
    Member
    Join Date
    Sep 2008
    Posts
    31
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Hey, the small wheel in the front and large wheel in the back serves more than the purpose of just going downhill all the time. That way, the generator motor is spinning much faster than the motor driving the bike so we can make MORE electricity than it uses. This way, we could even hook up all the charged up batteries to our homes to run our appliances after a long bike ride! This is such an awesome idea. Too bad I didn't think of it.

  13. #13
    Senior Member
    Join Date
    Aug 2008
    Posts
    536
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    just get a really long extension cord.

  14. #14
    Dog is my co-pilot 2manybikes's Avatar
    Join Date
    Jun 2003
    My Bikes
    2 many
    Posts
    13,557
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    This will do it.

    [ame="http://www.youtube.com/watch?v=PtuqjFf7-N4"]YouTube - Retro Encabulator[/ame]
    [SIGPIC][/SIGPIC]

  15. #15
    pedalphile
    Join Date
    Jul 2008
    Location
    ellington, ct
    My Bikes
    trek 1200, 520, Giant ATX 970, Raleigh Talon
    Posts
    1,027
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    ever see the tool on the youtube video who orives that his energy producing gizmo produces power by unplugging the motor from the wall?

    The motor, a really heavy fast spinning one, ofcourse, becomes a generator powered by the inertia of a few hundred pounds of spinning motorwinding. It easily kept a lightbulb running brightly. Probably would have powered that bulb for atleast 5 minutes. Wonder how many dopes bought that idea

  16. #16
    Senior Member misslexi's Avatar
    Join Date
    Aug 2008
    Posts
    218
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    My father-in-law has two of them

  17. #17
    e-Biker
    Join Date
    Aug 2006
    Location
    Mississauga, Ontario, Canada
    My Bikes
    Gary Fisher, Strong GT-S eBike
    Posts
    951
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by trekker pete View Post
    don't listen to this conservation of energy propaganda put out by "big oil".

    you can do it. you just need the right gearing!!


  18. #18
    Senior Member
    Join Date
    Aug 2007
    Location
    Minneapolis, MN
    My Bikes
    Surly CrossCheck, Miyata 310 (conversion)
    Posts
    854
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by trekker pete View Post
    don't listen to this conservation of energy propaganda put out by "big oil".

    you can do it. you just need the right gearing!!



    hahaha physics is just a tool of the devil




    ...
    derailleur? I hardly know her
    http://a2bikegeek.wordpress.com/

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •