wiring headlight setup...please help

GoldenMotor.com

GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
Blue wire is for powering the CDI box alone. If you tap power off of the blue wire you will kill the ignition system. Hook up the full wave bridge rectifier between white and black, which are both sides of the lighting coil on the mag.
Remember, the ignition coil (blue wire) and the lighting coil (white wire) are two separate windings on the mag that share a common ground which is the frame of the mag which the black wire also attaches to.
 
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Scotchmo

New Member
Jun 23, 2009
217
0
0
Los Osos, California
If you are only using one diode you are only using half of the AC wave. You could be getting twice the charge (time, not voltage) with a full wave bridge rectifier sold from places like radio shack for under $3 US. The pos. & neg. leads of the rectifier go to the battery, the other two leads go to the white wire and blue wire.
True. That is why the ½ wave system works on the white wire and the full wave has problems.

The white wire was not designed to be used in a full wave implementation. If you use a full wave, you are also utilizing the negative (-) half of the wave cycle through the white wire. The current caused by overloading the negative ½ of the wave will disrupt the CDI. If you pull too much current, you will kill the motor. The white wire coil is wound on the same core as the blue wire coil. Like the primaries and secondaries of a transformer. So they can affect each other. Full wave will also require an isolated ground bus which is more complicated and difficult to implement with lights that use grounded housings.

Use a ½ wave rectifier to tap the positive phase of the cycle and you can have a simple system that works under all conditions. It is a very low power system, but you can pull all the current it can deliver and it will not kill the motor.
 
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yodar

New Member
Jul 26, 2010
147
1
0
Orlando Fl
It doesn't. The 6v white wire will trickle charge the 12v battery. You run your lights off the battery.

:)
Say WHAT !?!?!
I've built power supplies and battery chargers for years, you need almost 15 volts to charge a 12 v battery

that aint gonnna come from 6 volts AC.

To charge a 6 volt battery you need more than 6 volts, how is that going to come from a 6 volt alternator after rectification and the little BOOST rectification given from AC you got MEBBE 6.4 volts and that isnt enough to recharge a 6V lead acid battery
 

yodar

New Member
Jul 26, 2010
147
1
0
Orlando Fl
You are not confused. 6 volts will not charge a 12 volt battery.
Most chargers as well as most automotive and motorcycle 12 volt electrical systems actually operate around 13.5 volts.

Voltage is the potential of power in a circuit.
Trying to charge a battery by introducing only half of the battery's potential is a no win situation.
13.6 V is the ACTUAL pure DC voltage out of a properly charged and fed 12 L.A. battery,. You need 14-18 volts depending on the current drain to charge a 13.6 v battery

I have been building AC/DC and DC to DC power supplies and inverters for years

I would not ask for any more that a couple hundred milliamps and at no more than 3.6 volts from that little Chinese alternator accessory. And I would drive a L.E.D.-array headlight (which i have )

That would solve the rectification and regulation issue that we needn't FUSS with.

LED's do the rectifying when they are putting out light. The LED's take maybe 100 m.a. and need only 3.6 V. - 4.5 volts.

It will run on SIX volts and be VERY bright, er, for a while ;>)

yodar

I will put a series load resistor to limit my current to the LED's

Yodar
 

blckwlfny1

New Member
Jul 14, 2010
128
1
0
new york
i solved the whole problem with a charger and generator from "wonderful creations" on ebay
im very happy with the setup i made using that to power it
i recommend his stuff. a bit pricy, but worth itzpt

Cheers
 
True. That is why the ½ wave system works on the white wire and the full wave has problems.

Use a ½ wave rectifier to tap the positive phase of the cycle and you can have a simple system that works under all conditions. It is a very low power system, but you can pull all the current it can deliver and it will not kill the motor.
I use the full wave with no problems, but I keep the current small by using LEDs and forgo the battery. The law says I have to have a headlight burning all the time like motorcycles. so I have two LEDs in the headlight wired in opposite directions, each burning on opposite sides of the wave. the result is a constantly burning light that's not bright enough for night time use but is a good signal in the day time.
 
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88cc_Ithink

New Member
Jan 12, 2024
3
1
1
Menifee, CA
Thats the kicker. You dont hook any lights up to the white wire and when your screaming down the road at high rpms the battery will charge.

You can run a 10-15 watt bulb off a 12v battery for probably 5 hours with out any kinda of charging system. Trickle it with 6-10+ volts and it will maintain a charge. Then you put your lights on a switch and only use them at night when you need it and that battery will be full of juice.

Tomorrow when I get paid Iam gonna order all the stuff.

Ill bet you an inner tube it works :)
just saw the posting re: no voltage being put out via the white wire…
On your meter, was it on A/C.?
Just trying to help - hope it does.
 

88cc_Ithink

New Member
Jan 12, 2024
3
1
1
Menifee, CA
just saw the posting re: no voltage being put out via the white wire…
On your meter, was it on A/C.?
Just trying to help - hope it does.

also, from what I’ve read AND experienced, the white wire is more headache than it’s worth; I’ve got a flashlight duct taped to my handlebars. It doesn’t look as bad as it sounds, but it WOULD be nice to have one that turned on when the engine started.
Can’t have it all I guess.
 

Wevil Kenevil

Well-Known Member
Mar 4, 2022
361
338
63
47
Sack a tomatoes California
This and or the stand alone accessory coil I think will do what you're looking to do with minimal confusion and a few bucks.