stator voltage & external battery packs

Discussion in 'The Garage' started by Rocket Scientist, Feb 19, 2013.

  1. Rocket Scientist

    Rocket Scientist Adventurer

    Joined:
    Jul 6, 2012
    Oddometer:
    24
    Location:
    Brighton,CO
    Looking to hookup a switched (12V dc) relay on my DR350 (non electric start) to fire the external battery pack that powers my lights. Turns out the stator output is only 6.3v dc & 13v ac. Wont keep the switch open to fire the battery supplied 12v to the lights. All the lights work great with a direct to battery hookup. Need to find a way to get a clean 12v dc off the stock bike to fire the relay, or other opinions are welcomed. Backs against the wall here.
    #1
  2. Beezer

    Beezer Long timer

    Joined:
    Oct 26, 2004
    Oddometer:
    6,060
    Location:
    Anchorage, formerly Spenard (hub of the universe)
    how are you getting 6 VDC? there would have to be a rectifier for that. if you have 12 VAC you rectify that with a diode bridge. easy way is to run the stator output into a rectifier/regulator.
    #2
  3. Grinnin

    Grinnin Forever N00b

    Joined:
    Dec 10, 2005
    Oddometer:
    3,044
    Location:
    Maine
    12VAC turning into 6VDC sounds like a half-wave rectifier OR a rectifier with half the diodes fried.

    You should be able to use a full-wave rectifier to get 12VDC off of 12VAC. I don't know DR350 so I cannot tell if you need to replace your rectifier or add a supplemental one for this circuit you are planning.

    If the bike really needs a 6VDC circuit, you could also use a relay with a 6V coil. Just look for contacts rated for more than 12V. (These small relays typically start with contact ratings for 30V and 10A and go up from there. Read the specs.)
    #3
  4. mouthfulloflake

    mouthfulloflake Not afraid

    Joined:
    Aug 21, 2008
    Oddometer:
    18,769
    Location:
    N.W. Arkansas
    How many wires from your stator?

    if its one yellow wire, its an ac only bike, there should be a small shunt regulator under the seat on top of the airbox ( my 1991 dr350 was like this)

    Only ac comes out of the stator on this set up, the shunt keeps it below 15 volts or so so the bulbs dont pop when you rev it.

    if you have 3 yellow wires coming out of the stator, you likely have a rectifier/regulator, on the kickstart side of bike, its about the size of a deck of cards., black and has cooling fins. it should have 12V dc coming out of it, all the time when the bike is running.


    those are the stock configureations for early Dr350 bikes.

    do you have something custom?
    #4
  5. Rocket Scientist

    Rocket Scientist Adventurer

    Joined:
    Jul 6, 2012
    Oddometer:
    24
    Location:
    Brighton,CO
    I was using the original headlight (yellow) wire for testing. The dc volts vary as the bike is reved higher. That wont keep my switch open at 6v dc. Ill trace back to the block on the top of the airbox & see what I get for voltage.
    #5
  6. mouthfulloflake

    mouthfulloflake Not afraid

    Joined:
    Aug 21, 2008
    Oddometer:
    18,769
    Location:
    N.W. Arkansas
    how many wires going to that block on top of the air cleaner?
    does it look like this?

    [​IMG]

    thats an AC shunt regulator
    No DC coming out of that.

    your meter might be measuring only the positive slope of the wave form , the upper half of the ac power, so maybe thats fooling your meter, and likely not constant enough to hold the relay coil energized.
    #6
  7. mouthfulloflake

    mouthfulloflake Not afraid

    Joined:
    Aug 21, 2008
    Oddometer:
    18,769
    Location:
    N.W. Arkansas
    also,

    you should have some empty posts on your stock stator, if you wind them with magnet wire, you can make a larger single phase, or 3 phase ( like the E start bikes) stator.

    check this link for some ideas.

    http://home.comcast.net/~pgailunas/stator.html
    #7
  8. Beezer

    Beezer Long timer

    Joined:
    Oct 26, 2004
    Oddometer:
    6,060
    Location:
    Anchorage, formerly Spenard (hub of the universe)
    if you do have half wave, a capacitor in parallel with the output of the yellow wire might let you use a 6v relay. it would fill in for the back side of the sine wave. the contacts on the relay will be rated in amps... thats the important bit... it has to be able to carry all the current in the system
    #8
  9. Rocket Scientist

    Rocket Scientist Adventurer

    Joined:
    Jul 6, 2012
    Oddometer:
    24
    Location:
    Brighton,CO
    Yea thats my bike. The meter Im using is a low voltage dc/with ac meter. So, how would you guys approach this if my bike is ac to switch & charge the dc battery pack for my lights?
    #9
  10. mouthfulloflake

    mouthfulloflake Not afraid

    Joined:
    Aug 21, 2008
    Oddometer:
    18,769
    Location:
    N.W. Arkansas
    just put a simple switch on the bars, and turn the battery pack on and off as needed?
    #10
  11. Beezer

    Beezer Long timer

    Joined:
    Oct 26, 2004
    Oddometer:
    6,060
    Location:
    Anchorage, formerly Spenard (hub of the universe)
    there is a couple ways to do it. depends on what you intend to run on DC. if you want to convert all the lights to DC then a rectifier after the regulator is what you want. or replace the existing regulator with a reg/rectifier from another installation. I imagine this has been done & info exists. (I have done this on other bikes and to get full wave rectification it required getting into the stator wires to isolate the frame ground)

    if you only wanted brake & tail light to be DC, you could tap into the AC output (I assume the yellow wire) and put in a wire for the battery + with a diode. that would give you half wave & would work if the battery load was not too high.
    #11
  12. ragtoplvr

    ragtoplvr Long timer

    Joined:
    Oct 18, 2007
    Oddometer:
    6,881
    Location:
    central USA
    IF you wind them the correct direction, with the right gage of wire, and the correct turns for the wire gage. It is not so simple is just go to radio shack get some magnet wire and wind some on at random

    Rod
    #12
  13. mouthfulloflake

    mouthfulloflake Not afraid

    Joined:
    Aug 21, 2008
    Oddometer:
    18,769
    Location:
    N.W. Arkansas
    I never said that was the absolute process, just an idea of what could be done to change his bike the way he wanted.



    Its not much more complex than that actually though, ive done a couple of them.

    you need to verify the orientation of your flywheel magnets, and usually its simpler to mimic the factory set up with wire diameter.

    the early DR 350 like he has, from the factory only has 1/3 of the coil wraps, its easy to fill in the blanks, and either have 3 redundant single phase electrical outputs, or a pretty beefy 3 phase stator.

    dirt version stator:

    [​IMG]


    electric start version stator

    [​IMG]

    and here is my dirt model stator after I wrapped the other 2 phases.

    [​IMG]
    #13
  14. Rocket Scientist

    Rocket Scientist Adventurer

    Joined:
    Jul 6, 2012
    Oddometer:
    24
    Location:
    Brighton,CO
    The idea was to run the handlebar switch exclusively off the 12v battery, that controls the headlight, both led turn signals, brake light, & horn. Wanted to use the bikes power source off the original headlight (yellow) wire & use it as the relay switch voltage turn on (only 6v dc & 13v ac turns out) to fire the battery that feeds all the lights. The guy previously had the headlight (yellow) tapped into the positive side of the battery, guessing to somehow charge the battery. My worry was having a constant 12v dc (battery) backfeeding into the stator when the bike isnt running. I can install a switch from the live (yellow) wire to the 12v battery feed & throw it once the bike is running as long as you guys think it wont burn something on the bike out. Id let the bikes power run the headlight as it did stock, & just run everything else off the battery pack. Good idea? Think the inline switch would charge the battery even if its at 6v dc? Will the ac interupt anything this way?
    #14
  15. Beezer

    Beezer Long timer

    Joined:
    Oct 26, 2004
    Oddometer:
    6,060
    Location:
    Anchorage, formerly Spenard (hub of the universe)
    tap into the yellow wire with another wire & take that to the battery with a diode that can handle maybe 10-15 amps. that will charge the battery and also prevent current backflow. the charging systems on yard tractors use this method. it is half wave & not very efficient but it works. if you have an AC regulator (seems you do) then that should work to prevent overcharging. the brake, tail & horn will have to be transferred over to the battery circuit & not connected to the AC for the headlight

    if you want a better system, get a different stator & R/R unit or do the mod above

    6v will not charge a 12v battery... I'm not sure you actually have 6VDC anyway
    #15