Light powered by engine

Discussion in 'Motorized Bicycle General Discussion' started by Scol, Mar 27, 2014.

  1. Scol

    Scol Member

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    I just finished my first build. It's a 80cc 2 stroke I going to
    fire her up tomorrow for the first time. ( pictures to follow )

    On the engine there is a wire out of the engine and the manual
    references that a light can be powered off this does any one know
    1. What voltage it would be ?
    2. Is the light any good
    3. What is the best type of light to get and does it take away
    any power from the engine.

    Shey,
     
  2. CTripps

    CTripps Active Member

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    The white wire is not very useful.. it should either be taped off or removed completely.. The little magneto's these engines pack just don't have the ability to support anything off the white wire and feed enough power to the ignition, despite the claims.
     
  3. 2door

    2door Moderator
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  4. DudeZXT

    DudeZXT New Member

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    I have a 3 AAA cell LED flashlight grounded to the frame and (+) wired to the white. While idling, the light is dim & flickering, but definitely visible. As I accelerate, the light gets brighter with the engine speed and seems to get as bright as it ever did with batteries.

    Simple to do, but I don't know that I would ever wire a lesser powered light to it - LED is perfect because it's polarized and doesn't allow harmful polarity to pass. I attempted to connect an identical LED flashlight as a tail-light, but it caused neither light to function, so I guess they must have grounded one another out or reduced voltage to not function - the engine never missed a lick, either way.
     
  5. 2door

    2door Moderator
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    I'm not disputing the fact that you can get a light to work from the magneto. What I'm saying is that the amount of light won't be enough for safe night riding. Just because there is a light out front doesn't mean you can see what's ahead.

    When I ride at night I want a light that is not just visible but shows me what I'm heading for. I maintain that you'll never get that from 2.5 watts.
    I run 35 and 55 watt sealed beams for headlights and power them from SLA batteries. I can get a solid hour of usable light that is near to motorcycle quality. You won't get that from a flashlight.

    Tom
     
  6. Going2Hell

    Going2Hell Member

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    if you wanted, you can get a single component cree HID led from superbrightleds.com and build one with advanced electrical knowledge. the problem is that the voltage can be anything in a reasonable range (2.5 - 36v) what matters is current, for leds its mA. these leds require at least 300mA and to provide awesome light, up to 800mA in some cases. this causes problems with the spark, killing the motor also.

    i spent 80 bucks and bought a sturmey archer xl-fdd. its a 6v 3w dynamo built into the front hub. some people make quality lights for dynamos at a steep price, im building my own power station to charge a cell phone, my lights and a sla battery. not at the same time of course...

    in all, if you just want to ride without worrying about battery charging... just go with a 30 dollar solar trickle charger. its 12v giving a larger range of lighting choice, its cheap, and its hands free. best of all, you get to keep 25% of your engines power.
     

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