6v custom headlight rig. need someone smarter than me

westonforbes

westonforbes

New Member
Hey,
I am trying to install a headlight i made on my 49cc bike, I am having some issues though and i need some help from anyone. First off, what I have built. I went to my local superstore and bought a handheld spotlight for like 7 bucks, I also bought some aftermarket car headlights. I took apart the spotlight and salvaged the 6v bulb and the 6v rechargable battery. I then removed the 12v bulb from the headlight and installed the 6v (exact same bulb but different voltage). I now have everything mounted with a containing box and I can run the light if i wire it directly to the battery but I cannot get it to run from the engine whitewire. I have tried many combinations, connecting directly to the engine and combinations involving the battery. I have a fairly good understanding of electrical basics but it just wont seem to work. I worry that the bulb may be too many watts and is not leaving enough for the sparkplug. If anyone has done a similar project I would love to hear about it! or any ideas on how to accomplish this. If i can get this working I will post a full lighting tutorial with pics and what to buy, cause so far this is a DIRT CHEAP lighting solution and it would help alot of people. Thanks in advance.
 
IMO trying to use that white wire is a poor choice. For one thing it robs powers from an ignition system that's marginal at best. If you don't understand the limitation it's very difficult to get it to work at all. With a diode to limit draw from the half of the cycle the engine don't use it's possible to get some small amount of power. Not worth the trouble though.

A 50-100 LED bicycle light using rechargeable AA cells runs for many hours and lights up the road like a searchlight. Cheap, reliable, light, and bright, I keep one in my pack to clip on for those rare occasions when I get stuck out in the dark. Even a small 9 LED flashlight will suffice. Or any old mini-maglite bulb type in a pinch.


westonforbes said:
Hey,
I am trying to install a headlight i made on my 49cc bike, I am having some issues though and i need some help from anyone. First off, what I have built. I went to my local superstore and bought a handheld spotlight for like 7 bucks, I also bought some aftermarket car headlights. I took apart the spotlight and salvaged the 6v bulb and the 6v rechargable battery. I then removed the 12v bulb from the headlight and installed the 6v (exact same bulb but different voltage). I now have everything mounted with a containing box and I can run the light if i wire it directly to the battery but I cannot get it to run from the engine whitewire. I have tried many combinations, connecting directly to the engine and combinations involving the battery. I have a fairly good understanding of electrical basics but it just wont seem to work. I worry that the bulb may be too many watts and is not leaving enough for the sparkplug. If anyone has done a similar project I would love to hear about it! or any ideas on how to accomplish this. If i can get this working I will post a full lighting tutorial with pics and what to buy, cause so far this is a DIRT CHEAP lighting solution and it would help alot of people. Thanks in advance.
Click to expand...
 
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I have a headlight and tail light that Norman makes and sells that runs off the white wire and it works very well. It puts out a lot of light and the engine runs just the same with light on or off...............
 
A typical 6 volt spotlight bulb is a 30 watt light...bike puts out no more than 3 watts from the white wire. It will not work from the white wire no matter how it is hooked up. If you want to use that light, you need to carry a battery.
 
Run a standard bulb in your setup not the one out of the spot light. A standard 3.5-6v bulb will run without any issues right off the white wire. Mine is plenty bright. I made it out of a cheap $1.79 flashlight, it was ugly plastic and yellow. I cut it up moddified it and painted it. All in all $2.50 maybe went into my light, I'll post pics later but it a pretty bullet style light and it is bright running off the white wire. So much white wire controversy....lol if people just researched what types of lights to use there wouldn't be so many issues. Like Hough said though a spotlight uses a lot of watts and the bike will not ignite the coil element.
 
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Oh btw dont run power out of that bike into that battery, you will fry it. Bike put's out AC from the white wire meaning the polarity flip flops. this will not charge a battery it will only damage it. If you try to run led off the white wire it will flicker at low rpms because it is only getting half the power wave. A voltage regulator/rectifier is needed to properly chg a battery without damaging it. I am running a 3v incandescent, bulb for my headlight and running 8 3.5v led's in paralell using my bikes frame as ground and white as my positive. Leds filcker because of the half wave but I am building a charging circuit, for batteries and to run the Leds properly.
 
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I figured it out before I rechecked this forum. After I posted this I whipped out my multimeter and found it indeed only produces 6v and 3w. which is enough to power pretty much nothing, and the bulb I was using was 55watts. So the whole project is scrapped. thanks for your rapid responses, I appreciate it.
 
xlite said:
IMO trying to use that white wire is a poor choice. For one thing it robs powers from an ignition system that's marginal at best. If you don't understand the limitation it's very difficult to get it to work at all. With a diode to limit draw from the half of the cycle the engine don't use it's possible to get some small amount of power. Not worth the trouble though.

A 50-100 LED bicycle light using rechargeable AA cells runs for many hours and lights up the road like a searchlight. Cheap, reliable, light, and bright, I keep one in my pack to clip on for those rare occasions when I get stuck out in the dark. Even a small 9 LED flashlight will suffice. Or any old mini-maglite bulb type in a pinch.
Click to expand...
xlite, when you say 50-100 LED bike light do you mean 50 to 100 LEDs? or is that some sort of rating. If you mean 50-100 leds thats pretty impressive and I would want one 5 minutes ago! where would you find such a contraption and how much do they normally run for? I was at the bike shop today and they had some high power LED lamps that cost more than i make in a week.
 
Hook a rectifier diode to the white wire and use that to trickle charge the battery when the headlight is not being used. That might be enough if you only use the headlight occasionally and you do enough driving during the day to recharge the battery. If you use that large headlight often, you will have to have some other method to keep the battery charged.
 
Here is my cheapo bullet light
 

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you could try using the solar AA batts & panel you find in many yard lights. thats what I used and they work great plus no need to buy new batts sun recharges everyday.
 
westonforbes said:
xlite, when you say 50-100 LED bike light do you mean 50 to 100 LEDs? or is that some sort of rating. If you mean 50-100 leds thats pretty impressive and I would want one 5 minutes ago! where would you find such a contraption and how much do they normally run for? I was at the bike shop today and they had some high power LED lamps that cost more than i make in a week.
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Dealextreme.com has about a dozen different LED bike lights and the one I got was $8 shipped. They run around 8x that price locally. 4 intensity settings plus flash. It lights up the road like magic and gets about 5-6hrs with 4 AA rechargeables. Note that it's a little brighter with alkalines but I'm not made of money. :)
 
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