White Wire Voltage - 20+ V ??

Discussion in 'Electrical' started by npk1977, Aug 6, 2007.

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  1. npk1977

    npk1977 Guest


    I finally got my bike running this past weekend! It's not as nice looking as my old bike, but at least I've got something :) Note, that the first paragraph that follows is the executive summary. The following paragraphs are at a more technical level.

    CAVEAT: My spark plug may need to be tuned!

    As promised, I measured the output voltage from the white wire, in the hopes of eventually designing and building a high-quality lighting system for these motorized bikes. The output voltage was something like 20V to 25V. When loaded with a 10kOhm resistor, and the motor died, implying that the motor can source less than 0.06 Watts! (This is why I'm guessing I need to tune my spark.)

    The setup was as follows: I duct-taped a "ground" wire to my steering column. A 3' wire was connected to the black cable. Measurements were made between those two wires.

    The output waveform was not a nice, beautiful looking, sinusoidal wave, but rather a very strange looking waveform. The positive swing looked half sinusoidal, but the downward swing shot off the bottom of my oscilloscope. Until I can photograph my oscilloscope, this is the best desc available :)

    The white-wire output was connected to a diode bridge rectifier (DF005M) and a 0.1uF smoothing, electrolytic capacitor. Output was loaded with the 1MOhm voltmeter and a 10kOhm resistor. Bike would not start with the 10kOhm connected.

  2. Herrmanator8

    Herrmanator8 Guest

    :confused::confused: i didnt get any of that...as far as i know, the white wire puts out 6 volts 3 watts. correct me if i'm wrong. possibly a transformer could bump up the voltage a little for your big light system thingy.

    since i can tell you know something about electronics, i have a wheel based friction generator on my bike and i connected it to my rear light and my headlignt, the rear light has never blown but the headlight bulb always blows in a matter of minutes. i guess 30mph is too much electricity for it. i now have the white wire on my headlight. but, is there some type of resister that i could get to step down some of the electricity that its generating? tell me if there is please.

  3. npk1977

    npk1977 Guest

    See, I'm confused too. Everyone says the white wire pumps out 6V/3W. I'm not really sure what the heck is going on! I do hope to figure it out soon though :)

  4. davidsis

    davidsis Guest

    6v 3w

    ya, figure it out. I am really bad at electrical things, and I need a light bad, so I can ride in Daytona. Please keep me posted really want lights I need a head light and a tail light and a brake light to ride in Daytona.
  5. npk1977

    npk1977 Guest

    Whatever I come up with will be home-grown and kind of janky :) However, the hub lighting systems look like they are high quality, and will not blow up at high speeds:


    I'm sure you can find a good place to order them for cheap online. (ie, not necessarily the link i sent.)
  6. davidsis

    davidsis Guest

    brake lights

    I think I just solved my brake light problem
    look on e-bay item #220135635600
    Brake pads that light up when you put the brakes on.
  7. npk1977

    npk1977 Guest

    They seem nice, but only 2 LEDs? Not sure how much light that will pump out. Also, what happens if you decide to use saddle bags?
  8. npk1977

    npk1977 Guest

    Ok, who on this board has a voltmeter (or digital multimeter.) I'd like to mail you a little circuit for testing. You need to have

    1) A mailing address
    2) A multimeter/voltmeter/whatever you call it.
    3) A Working, well tuned motored-bike
    4) The willingness to mail the circuit back, and email me your results :)
    5) I live in Santa Cruz, CA, so if you happen to live in town, even better.

    I can't figure out what's going on with my bike, I'm getting enormous, 24V, voltages :)

    The circuit is incredibly simple, consisting of three discrete components, a diode bridge, a capacitor and a resistor. It converts the variable output of the CDI into a nice, smooth, DC signal.

    PM Me.
  9. dave1490

    dave1490 Guest

    you can use a resitor to give you a voltage drop but it will affect all speeds not just 30mph.
  10. npk1977

    npk1977 Guest

    I measured the output voltage again, and now I think everything is well tuned... Again, Vout was in the high 20s. Does anyone have experience with this?
  11. npk1977

    npk1977 Guest

    Ok, I spent 30 mins on my bike with the white wire system. Same circuit as above, diode bridge with 0.1uF polarized capacitor.

    Step 1) When the bike is warmed up, it puts out 28V-30V with NO load.

    Step 2) I used a 330Ohm load resistor, voltage was fluctuating between 10V-15V. I need to get my oscilloscope on the bike. Simple interpretation is that the output power of the white wire system, on my bicycle, is something like 0.3W-0.7W. Significantly LESS than the 3Ws advertised. However, power output increases over time (See my first post.) Furthermore, output voltage is definitely not 6V!

    Conclusion: as the engine breaks in, the electrical power out increases significantly. Hopefully in a hundred miles or so I'll get my 3W of electrical power. In addition, I really to measure the waveform of the voltage (i'll get to it in a few days.) Finally, if anyone has contact with a 2stroke mechanic who knows something about electricals, I'd like to talk to them :)

  12. gone_fishin

    gone_fishin Guest

    maybe slightly OT, but i thought you might like to know this...the "performance" 65 i'm running right now seems to have the normal/standard magneto (blue output)...

    i hardwired a 6V/3W headlamp from day one, it started blowing bulbs immediately...

    i'm up to a 12V/8W and finally it's doing fine...still starts with no hesitation and runs like a true beast (well, a tiny true beast).
  13. npk1977

    npk1977 Guest

    No, not OT. (1) The goal of this is to power a light source. (2) A 12V/8W bulb has a resistance of ~20Ohm a 6V/3W bulb has a resistance of ~12Ohm. I should be able to reproduce your results with my motor, so you've provided two useful data point.

    Would you be willing to plug a circuit of mine onto your bike and tell me if it improves your bulb? Could you compare it against an LED flashlight? :)
  14. Generator needs a large rubber wheel over stock cog to turn slower. mine never burns out. Make sure of good ground wires.
  15. npk1977

    npk1977 Guest

    Martin - You're talking about a dynamo generator that rubs on the wheel? We're talking about power from the magneto. Apples and oranges.
  16. gone_fishin

    gone_fishin Guest

    gladly :cool:
  17. thatsdax

    thatsdax Guest

    did you...

    Did you have your meter on AC or DC ?
  18. thatsdax

    thatsdax Guest


    Also..To build proper Vreg. You will need a Zener circuit. Go full wave into a Zener. Use a Cap to smooth the ripple. Main thing is to use a Zener for voltage regulation so you do not over charge any NiCads you may be using to drive the light. Idea here is to limit I or Current so it does not take away from Spark. So.. Remember to put in a I limiter R value to limit current. A zener to Regulate Voltage, and a cap to smooth the ripple.. In Aggregate, what you would like to have it Nicad driving the bulb or bulbs at night. During the day, while riding you have a trickle charge going into the nicads keeping them up for the night ride. You Electronic techs and Electronic Engineers know what I am talking about. I know some of you guys are in here...I can tell..Enjoy the ride..

    RATRODER Guest

    Could you use a white LED for your headlite in place of the 6v bulb? LEDs use very little current.
  20. How about finding a bigger wheel to replace the wheel on the end of your generator,cause a bigger wheel would turn slower. Were talking maybe 1/8th diameter difference at best.
    Or maybe (and this can get real technical) find a way to mount that generator to your rear sprocket? It would most definetly turn slower...that would be so far out as to be actually cool.
    Last edited by a moderator: Aug 24, 2007