Secondary magneto coil for lights/acc?

GoldenMotor.com

HseLoMein

Member
Oct 30, 2008
125
6
18
Boston, MA
xenodius,

Here's a post from someone who installed:
http://motorbicycling.com/showthread.php?t=35871

Just FYI, the Ebay listing states that it produces just over 12 volts at 1300 - 1500 rpm - driving speeds of 15 to 18 mp/h. So your not going to get 12 volts at idle as you wished in your OP.

Good Luck,

Chris
AKA: BigBlue
Magical Creations RPM calcumations are wrong, these are high idle engines, and they usually idle around 1700 to 2000 RPMs. SO you should be fine at idle.
 

HseLoMein

Member
Oct 30, 2008
125
6
18
Boston, MA
Are you testing your setup at idle or full power? Per the Ebay listing, the Mini-gen doesn't produce 12 volts till 12 - 15 mph. 18 volts or more @ 1.5 amps is not reached till high speed? What ever that is.

From the Ebay listing:

The engine speed here is around 1300 to 1350 RPM which is just around driving speed.
Most riders will produce this voltage at a speed of around 15 to 18 MPH.
Higher voltages of around 18 or more is obtainable at much higher engine speeds, but 12 volts is specified as the average voltage.

Also, per the Ebay posting states not to rev of 3000 rpms more than 5 seconds or you'll blow your bulbs.

What is the voltage, amperage and wattage of the headlight? What are the voltage, amperage and wattage of your instrument light and tail light?

Normally, you connect the headlight to the A/C output on the rectifier/regulator. You could run the instrument bulb and tail light off the D/C battery, depending on how much they draw on the battery. My guess is that they draw more than what the generator is charging. It is not a good on the battery if you are drawing more than charging. Depending on your amperage of your tail light you may have to run it off the A/C.

I don't recommend you connect your headlight to the A/C till you know for sure it will not blow the LED bulb(s).

FYI, the rectifier converts the A/C voltage to D/C voltage and the regulator regulates the D/C voltage to around 12 volts for charging the battery. I assume your rectifier is also a regulator and that you know the pinout of your rectifier/ regulator.

I have a limited understanding of electronics and wiring. Maybe a more knowledgeable member can chime in.

Good Luck,

Chris
AKA: BigBlue
I dont think that the RPM estimates are correct. I have never seen a HT idle lower than 1600 RPM. I know my bike stalls at anything less than 1600 RPM. sometimes i can sneak it to 15 but it doesnt last long. My bike idles @ 2k RPM.
 

Scootmeister

Member
Mar 15, 2011
243
5
16
North Carolina
Harold B, I went to Radio Shack and picked up a 25 ohm rheostat and wired it into the headlight circuit thinking I could limit amperage to the LED headlight, leaving some for the other two lights. The rheostat allows me to adjust the intensity and color of the LED headlight, but the other two lights still do not work with the headlight. I'm beginning to believe my problem is my vintage Yamaha rectifier. The folks at Mighty Wonderful Creations advised me that Mini-Gens do not work well with rectifiers if lights are grounded to the frame, so I isolated all of the grounds through the ground wire on the rectifier which leads to the frame(don't see the difference, but I'm no genius). Anyway, I will pick up a cheap scooter rectifier/regulator at the local scooter store and try that. Thanks for the tip on the battery, was thinking along that line too.
 

Harold_B

Active Member
May 23, 2012
997
246
43
Grand Rapids, MI
Mighty Wonderful Creations sells a rectifier/voltage regulator that you can use for charging a battery as the bike runs. I have that set up on my bike. I did not care for the performance of the lights when connected to the output designated "light switch" so I wired the switch directly to the 12vdc battery terminal (+). The lights are on whenever I ride and the voltage has not dipped below 11vdc as measured on a gauge mounted on my bars. The headlight still dims when I hit the brake but I expect that to change when I swap out the bulbs in the taillight and brake light for LEDs. The only other issue I have is that the ammeter I have inline with the MWC coil does not show anything going on. Not sure if the Lead Acid battery is just recovering between rides or if the meter is not working.

Anyway, my point is that you might consider their matching product instead of trying to find something that will work.
 

Scootmeister

Member
Mar 15, 2011
243
5
16
North Carolina
Thanks Harold B. I'll check the MWC unit. It's interesting that MWC says you can wire LED lights directly to the A/C output on their coil. Some members have reported success doing that, mine just don't work on A/C. Besides, I'm not sure I need a brake light or turn signals, but I would like to have a horn which needs DC. The MWC unit would work if I could wire the LEDs to an A/C output and wire the horn to a DC outlet. While I'm tryiing to figure all of this out, I'm reworking the centrifugal clutch on my other ride. I tuned the 50cc Homelite engine and the extra HP broke the sprocket loose from the clutch bell!!!!! When I re-welded the sprocket I got careless and melted one of the teeth. Lucky me, I got to rebuilt the tooth by building up a weld and shaping the tooth with my dremel. Worked great, thank goodness. Can't wait to see if I get any increase in MPH with a highly tuned engine.