6v to 12v?

Discussion in 'Electrical' started by fenderhole, Mar 2, 2009.

  1. fenderhole

    fenderhole New Member

    is it possible to upgrade the 6v magneto in our engines with one that has 12v output?

  2. Mountainman

    Mountainman Active Member

    haven't seen that done around here fender

    you could have an elect shop make you one up (( custom )) pretty penny !!!

    not sure your unit will support enough 6 v juice to supply 12 v step up transformer ???

    the elect guys should be here soon -- so as to ssave the day...

    ride the motor bike
  3. loquin

    loquin Active Member

    The amount of power output from the coil is fixed. You could feed the output through a step-up transformer, but, there are issues that you need to be aware of:
    1. Since the maximum available power output on the white wire is fixed at about 3 watts, doubling the voltage would halve the current. (Power = Voltage times Current)
    2. Transformers aren't 100% efficient. You would lose some of the available power in the transformer.
    3. The frequency of the AC voltage varies - as the engine speed increases, the frequency of the pulses also increases. But, transformers are normally designed to work at peak efficiency at a given, fixed frequency. (60 hertz in the U.S.)

    Stepping up the voltage isn't all bad news though, Since the power loss in a diode bridge (used to convert the AC voltage to DC) is based on a fixed voltage drop across the diodes and the current through them, the diode power loss would be halved. Standard, silicon diodes in a bridge circuit drop a little less than 20 percent of the available power in a 6 volt system. In a 12 volt system, this would drop to about 10%.

    IF there is room inside the flywheel, and the crank case has adequate hard points for mounting it, adding a single-pole stator would probably be the best approach. A stator producing 60 watts would pull about 1/10th of a HP from the engine.

    If there's an EE reading this, please add your thoughts.
    Last edited: Mar 3, 2009
  4. fenderhole

    fenderhole New Member

    a new stator is kinda what i had in mind. you know, something that would bolt in with a little modification. any ideas on where to look for that? pocket bike? scooter or moped perhaps? if not, i guess i'll try running lower draw bulbs or possibly a series of LEDs, although i've read not many people have had luck using those. i just want to power a headlight and tail light off the motor. it will run one or the other but not both it seems.
  5. fenderhole

    fenderhole New Member

    whoa, check out this light. it may have great potential for all of us 'white wire guys'.... Ebay Item number: 290299080907
  6. loquin

    loquin Active Member

    I've never looked under the flywheel on a HT so I don't know how much room they might have. It's possible, if you were to find a multi-pole stator from a different motor (check here for ideas - the two-coil stator might work to pull one of the stator coils off the assembly, and mount it in place...)
  7. duivendyk

    duivendyk Guest

    I am such a person.What would be the motivation for doing this?.This so called '6V' output is in fact a weird looking ac.output consisting of short ac pulses of unequal pos. and neg. excursions, with no output in the duration between them.These pulses are of variable amplitude (roughly proportional to engine speed) .The only reason they are called 6V by the uninitiated is that you can light up a 6V incandescent light bulb with it.If you want to try to charge a 12V battery,I can give you some circuits that could work,but first give me an idea what you are about.Do you have a multi meter and some passing acquaintance with things electrical?Trying to run constant voltage dc. devices like LED's directly from that kind of ac. source is risky,some LED's can't stand much reverse voltage,also once you exceed the firing voltage (around 3.5 V typically) the current increases quite rapidly,so you stand a good chance of either stalling your engine or blowing up the LED.it's better to store energy by charging a battery,this also can give you a 6 or 12V source instead of that messy varying ac.output.I very much doubt that a secondary coil can be implemented,it has to conform to the radius of the flywheel VERY closely (within 1/32") , then you have to find the space to put it,it also has to match the circumferential dimensions of the flywheel magnet in order to close the magnetic circuit and get any useful output
    Last edited by a moderator: Mar 3, 2009