6 Volt LED headlamp w/ small 6 volt motorcycle battery

The guy at the autoparts place told me to use a small 6 volt motorcycle battery and run the white wire to it, then run a wire from the battery to the headlamp so the motor would not be using the spark juice to power the light.
I purchased two LEDs from Radio Shack (3.6volts, 20mA, 1100mcd) to use fro this project.

Any thoughts on this?
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PK-80 Powerking Limited motor, 26" 7-Speed Schwinn "Point Beach" Cruiser
Top Speed: 31mph (Break-in period)
 

Cabinfever1977

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Mar 23, 2009
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use a 18v cordless power tool battery$20 and 1hr quick charger$20
2 car lights hooked together=24volts$12,1 fuse and 1 on/off switch $5
all from walmart
 

gberry50

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Jun 16, 2009
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snowflake,az
Go to radio shack ask for full wave bridge rectifier mine cost 3.39+tax
Run white wire to ac+ spade connector and although not marked run lighting wire
from the other + spade connector
I run two 1 watt niteize leds in headlight and one 1watt niteize in tail light
I'm going to connect a small lead acid 6 v battery in line with the dc tap on rectifier
when mounting rectifier make sure you sand off paint for grounding.
 

Hot Dog Piggy Tails

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Sep 11, 2008
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Kelso Wa
I get my Rectifiers from Radio Shack also. Sorry about the delay. The ground can be ran two wire also so as not to worry about the mounting ground!. and for LED's youll acheive the most power in series 1watters 3 deep (4 volt) or 6 volter's parallel.

I was quite blown away when I plugged my first rectifier IC into a 1 watt diode and blew it immediately. one in series then two in parallel works good all 6 volt one watters.
 
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Hot Dog Piggy Tails

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Sep 11, 2008
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Kelso Wa
use a 18v cordless power tool battery$20 and 1hr quick charger$20
2 car lights hooked together=24volts$12,1 fuse and 1 on/off switch $5
all from walmart
Oh Cabin fever Ooh that name gives me the willies'

series you mean. power to + out it's -.. to + of second light out of its negative back to the batteries - terminal. resistive load can handle higher voltage than rated for each bulb x2
 
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gberry50

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Jun 16, 2009
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snowflake,az
I would like to try a 3watt led in headlight but I have learned on this forum that the output of lighting coil is only 3 watts is this true?
 

Hot Dog Piggy Tails

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Sep 11, 2008
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Kelso Wa
yes but..but the more efficint of a bridge rectifier circuit the more power youll acheive. so no Ive never been able to pull 3 watts only with a special circuit even straight ac ..about 1.5 watts and you have to narrow the sparkplug gap depending on resistance of the lumen generated and the efficiency of the bulb.

Th dc circuit tends to run a little smoother as then you are using a diode. the bulbs resistance has a lot to do with the performance of the stater tap (white wire) it seems youll acheive a dwell with our crude works in ac
 
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Scotchmo

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Jun 23, 2009
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Los Osos, California
Rather than using a full wave bridge, you might want to try a single diode as a half wave rectifier. The CDI appears to charge during half of the wave form. A half wave rectifier will let you use the other half of the wave form for battery charging. If you use a full wave bridge and you pull too much current for your charging and lights, you will kill the spark. Most of what I have read indicates that the CDI uses the positive (in relation to ground) half of the wave form. My bike uses the negative half. So the polarity is not the same for all engines.

An easy way to test: Hook a diode up to the white wire. Short the other end of the diode to the engine while it is running. If it kills the spark, reverse the direction of the diode and try again. If the engine continues to run even with a short, than it is hooked up right. The stripe on one end of the diode indicates the positive side.
 

Hot Dog Piggy Tails

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Sep 11, 2008
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Kelso Wa
the anode is the negative(input) and the lined side ..the cathode.. is positive. a forward bias is needed to work this electronic so the line is the out put half wave (1/4 cycle) rectifier.
 

TheE

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Jun 26, 2009
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The best way I can think of would be to connect the striped end of the diode to the + terminal of the battery, and then the other end of the diode to the white wire. That way, when the battery drops below (white wire-0.7V), the diode will conduct to charge it back up. If it's causing your motor to stop running, consider a current-limiting resistor.

Connecting the diode the other way around will cause the battery to charge the magneto...NOT what you want.
 

Scotchmo

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Jun 23, 2009
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Los Osos, California
You don’t just reverse the diode while leaving it hooked to battery positive. When you reverse the diode, and you have a battery, you must also reverse the poles of the battery. The test I suggested was done without a battery.

The test was simply to determine whether a positive or negative ground system would be best for a given motor.

Here are the two options for wiring the battery:

Negative ground – The negative pole of the battery is grounded to the motor/chassis. The cathode side of the diode (stripe) is hooked to the positive pole of the battery and the other end of the diode is hooked to the white wire.

Positive ground – The positive pole of the battery is grounded to the motor/chassis. The cathode side of the diode (stripe) is hooked to the white wire. The other side of the diode is hooked to the negative pole of the battery.

I explained it as I did above because I prefer to run the ground directly from the battery to motor/chassis with no components in between. But, for the positive ground, you could also have the cathode hooked up to the positive pole of the battery and ground the anode.
 
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PatMcLJr

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Jun 21, 2009
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earth
any one got a diagram?

could I use 4 D cell NiMh batteries for my battery or does it need to be lead acid?

Thanks,
Pat Jr.
 

Scotchmo

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Jun 23, 2009
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Los Osos, California
I stayed up till 4am last night working on my charging system and wiring harness. I finished it this afternoon and went for a 15 mile ride. It is finally street legal so I rode it to the next town and back. I was only running a brake light intermittently so it was not much of a test. But nothing fried and it still works. The battery voltage does rise slightly when I rev the engine. That is a good sign. But the half wave rectifier has only very minimal current output. I’ll try it with the headlamp and taillamp tonight. The 1.3ah battery should be able to handle that load for about 20 minutes on its own. I’ll see if the charging system extends the run time of the lights and how long it takes for the battery voltage to be brought back up when I run with the lights turned off again. Eventually I’m going to use LED lighting which should help.

I may post a diagram next week, but I need to verify and test some things first.
 

gberry50

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Jun 16, 2009
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snowflake,az
I am running a full wave bridge with 3 1 watt led's works fine! bike runs 25 mph uphill with the ligths on. still on the first tank of gas. battery ordered will update soon.

k.i.s.s.---keep it simple stupid.