Generator idea.

Discussion in 'Electrical' started by crazyman, Dec 27, 2008.

  1. crazyman

    crazyman New Member

    All of these engines, no matter who makes it, have a rotating magnet on the flywheel that makes voltage in the coil for the ignition.

    An ignition coil wouldn't work for my idea due to the high voltage level. However, any small piece of steel with wire wrapped around it will make AC voltage when it's mounted next to the magnet, somewhere on the shroud or on the block. Turn ratio and wire diameter would take some experimenting to get the volts & amps to where they are needed.

    On mower engines, unregulated, they make between 15-22 volts. Just add a simple lawnmower voltage regulator, and you have 12 volts that will power lights.

  2. Mountainman

    Mountainman Active Member

    I think that you could get that generator THING going there crazyman

    are you going to be a working on that ?

    keep us posted

    always to remember have fun as you -- ride that MB THING
  3. kcmcf

    kcmcf Member

    i was thinking about trying to build my own . kind of like they use on wind gen's shouldn't be to hard. here is a link for all kinds of diffrent home built power stuff.
  4. ZnsaneRyder

    ZnsaneRyder Member

    I've been interested in winding a homemade coil as well. The big issue is where and how to mount the thing. May even have to modify the cover.
  5. crazyman

    crazyman New Member

    Last edited by a moderator: Jan 5, 2009
  6. Heres my perliminary idea ..


    Mounting is done with 2 jubile clips, and an old alan key! is very stong mount actually..
    The wheel is glued with superglue to the small gear, it can withstand the heat as it doesnt get very hot :) and can easily be broken off i'm sure!
    and yes the case DOES fit on fine over the top, need to make a hole in it but i'm not at that stage yet ..


    Motor makes 20v at idle, very little current though, a dynamo is needed
    The elastic band will slip if wet, some other method of transfering drive needed

    Future things:

    different placement, more powerful motor/generator
    alternate method

    ps this is not a thread hijack, i don't think my idea is worthy of a thread just yet but this is my idea

    the lawnmower generator thingy looks more promising, just need to actually have someone get it attached! People have talked of putting a motor on the drive and so i've done my part, just need to keep on working
  7. lordoflightaz

    lordoflightaz Member


    The things I learn just reading new posts. I have been thinking about a generator for the bike. I already have a small motor that was used to make a doggie door go up and down. Looking at your picture I think you would be better off mounting that little motor to the clutch cover on a small aluminum frame instead of the bike frame. With that in place I just need a USB cable to charge my NiteRider's Battery.
  8. bluegoatwoods

    bluegoatwoods Well-Known Member

    The frame mounted generator looks promising.

    As far as mounting a coil outside the magneto case goes; do you think the magnetic field would be strong enough, at that distance, to generate any real power?
  9. duivendyk

    duivendyk Guest

    Forget the idea of building your own induction coil,it's a waste of time &effort,the reasons are the following:
    1) a piece of soft iron will not do,the eddy currents induced in it by the changing magnetic field will largely neutralize it,leaving little net field intensity to induce a voltage in the winding,so the efficiency will be low,all you do is heat up the piece of iron,a laminated transformer steel armature is required,to keep the core loss down
    2) The clearance between the armature and the flywheel magnet has to be quite small in the order of 1/64"or less (0.4 mm) in order to get a strong enough field, necessary to induce a useful voltage without requiring an undue number of turns and excessive resistance in the coil,resulting in low power output and high losses.
  10. ZnsaneRyder

    ZnsaneRyder Member

    I can get laminated transformer metal from old transformers that I already have, and use a dremel to cut it to the proper shape.

    The coil wire makes a good point. It would take a lot, but if we could get even a small amount of power that's more than the ign wire, than it would be worth it to me.
  11. machiasmort

    machiasmort Active Member

    Giles, great idea man! Now I'll share one of mine with the board that I've had in my head for a while.

    Nice to know somebody is serious here! How about turning a GMAC car alternator with the back tire off of a homemade mount????
  12. bluegoatwoods

    bluegoatwoods Well-Known Member

    Could a bicycle tire spin an automotive alternator fast enough to produce 12 Volts?

    (the voltages is dependent on the speed, isn't it? I think it is)

    I also suspect that if you could get the setup to produce any real power, then it would use up somewhere around half of your engine's power to do it.

    But I'm being a bit of a nay-sayer. Sorry. I don't really know that these objections hold water. I only think they might be trouble.

    someone will come along who really knows.
  13. POPS

    POPS Member

    A healthy auto alternator is supposed to put out 14.5 volts continously. AS speed increases or decreases the voltage reg. keeps it in check at 14.5 volts. When a car is at idle in gear (auto trans) it still puts out 14.5 volts. Turn on all accesories (lights,air,etc.) and the reg. compensates to keep 14.5 so with that being said I believe that one could run an ault. off the rear wheel with the right gearing to keep it spinning at a 600 RPM min. The only problem I can see is it will eat up too much power from the motor to drive the ault....POPS
  14. MotorMac

    MotorMac Member


    It would also be too big and bulky too.
  15. POPS

    POPS Member

    One could use a small import alt. to get around that but the power draw would be the major issue...POPS
  16. machiasmort

    machiasmort Active Member

    Word of caution, As tempting as it may be!!! I knew this idiot once that connected a motor to a dremel tool inorder to see what kind of voltage it would throw back under high speed. The idiot held the motor in one hand and the dremel in the other. Hand holding dremel sliped and switched dremel to highest setting causing motor to explode. I had parts of the can from the motor stuck in my cieling tile!!! My hand was uncut but numb for a week!
  17. crazyman

    crazyman New Member

    I apologize. I keep forgetting about the frame mount guys. I have a trimmer engine, and was thinking along those lines. Mounting it through the plastic cover.

    Giles, how about making some sort of sliding coupler, and mounting it direct drive through the cover?
    Last edited: Jan 10, 2009
  18. duivendyk

    duivendyk Guest

    Any car alternator is really an overkill powerwise,it will put out 14.5 V at 900 rpm or so and deliver 25 Amps or more, easy.They are quite heavy ,15 lbs or so and need to be operated connected to a 12V battery.The idle drain is probably not more than .05/.1 HP.If a smaller motorcycle type alternator could be found,that would be a much better choice,however these are usually not available as self-contained units but are an integral part of the crankshaft assembly to the best of my knowledge.
  19. Youngbird

    Youngbird Member

    A Harley generator will work for this, but priced at about $139. and up it is cost prohibitive for me right now, but thats the way I will eventually go. Its 12v and will run all the lights and elec. gizmos you can think of.:(
  20. machiasmort

    machiasmort Active Member

    I was looking at the possibilty of running two batteries and charging them while ridding, off of the alternator, (free power)!