White Wire Voltage - 20+ V ??

[Hot Dog Piggy Tails]

to your magneto/magnet the faster your magnet is spinning the more constant the electricity is building therefor at higher speeds the gap becomes easier to jump and the current allows more maybe the magnet is stronger under these conditions thus putting out a higher voltage at revs but as far as your magneto goes check the resistance of your white wire to the magnetos c shaped body and you should have around 2-3 ohms. if its more then there could be to many wraps before the tap on your primary

 

[MotorMac]

This all sounds incredibly complicated, do what I do ,if planning to go out at night just hook up a powerfull 55 watt halogen driving lamp to a tiny little 12 volt battery fastened under your seat post, its good for 1 hour, or you can get one thats 2 inches bigger for 2 hours of running time heres a picture of the smaller battery.http://www.batterybuyer.ca/detail.asp?PRODUCT_ID=GR12V4.5

 

[Flapdoodle]

I have a Happy Time model H2-80 according to the vendor. Measuring between the white and black wires I got 33 VAC with a little throttle.

Two 3.7 volt LEDs in series lit at idle, blew instantly when throttled up.

Using a diode, 220 uf cap and a 170 ohm resistor for load (about 83 MA), it reads ~11.8-12.2 at idle, and 14.1 to 14.2 about 1/2 throttle. This can't be a 6 volt system. I suspect the Chinese have upgraded these to 12 volts. Anyhow, this is perfect for charging a 12 volt battery.

 

[Hot Dog Piggy Tails]

ac to dc

ac is not what you want to send to any battery ,direct current. you should buy 4 diodes and a regulating resister a battery and a cap

 

[Flapdoodle]

ac is not what you want to send to any battery ,direct current. you should buy 4 diodes and a regulating resister a battery and a cap

I have been designing power supplies for over 30 years and can assure you one diode and a hefty cap will produce DC from AC.

 

[BSA]

I've actually measured the magnetos output on my engine and it was around 4 volts at idle, and 6 volts with moderate revving. As the engine wasn't under load, and not wishing to over rev I didn't test high revs, but know doubt they would get up to at least 8 volts.

BSA

 

[Hot Dog Piggy Tails]

half duplex dc I didnt see anywhere in your paragragh about a diode and yes this is true.

 

[Flapdoodle]

Mine outputs about 8volts at idle and just over 12v at throttle .. don't know how youre getting 20v!!
I have used a rectifier (to convert AC to DC) and produces a fairly bumpy wave form but its usable and constant! Charges a 12volt 2.9amp battery fine, wired with a diode so when you use kill switch it doesnt short out battery

Thanks Giles. Good to know.

I put together 16 high intensity white LEDs in an array 4X4. That is 4 diodes in series and 4 banks. Rated max volts 14. They are rated at 3.5-3.7 volts @20ma. This makes my rather odd looking 12v headlight. Four LEDs (also series wired) at the rear for tail lights, and a bank of 10 LiMh cells (for 12.5 volts) that will be trickle charged during the day.

I will supply photos soon.

 

[BSA]

Mine outputs about 8volts at idle and just over 12v at throttle .. don't know how youre getting 20v!!
I have used a rectifier (to convert AC to DC) and produces a fairly bumpy wave form but its usable and constant! Charges a 12volt 2.9amp battery fine, wired with a diode so when you use kill switch it doesnt short out battery

Please tell us more about your setup. Pictures? I wonder why yours give such a high output, when most are always around 6 volt.

cheers

BSA

 

[Flapdoodle]

I made a few quick drawings.
This is the magneto showing the resistance I am reading...
http://flapdoodle.250free.com/80cc/magneto.gif

This is the test circuit I made to measure the voltages...
http://flapdoodle.250free.com/80cc/magneto2.gif
Note that the resistor (in red) is only there to give it approximately what I expect my trickle charging load to be.

This is the charging circuit...
http://flapdoodle.250free.com/80cc/magneto3.gif
The resistor value will be adjusted to give about 40ma that I consider safe for long term charging for the LiMH battery pack I have chosen.

This is the headlight...
http://flapdoodle.250free.com/80cc/headlight.gif
It is plenty bright enough for my needs. It draws 80ma for 1 watt (about twice the charging current). Tail light is 1/4 watt.

It is important to remember that using the low voltage output in this manner makes the frame positive (positive ground) relatively speaking. In other words, I can ground the positive of any 12 volt device to the chassis.

Unrelated to this thread, but I have thrown in the kill switch I made...
http://flapdoodle.250free.com/80cc/kill_switch.gif
It is in series with one wire to the CDI to give me more peace of mind.