Bullet light LED conversion

GoldenMotor.com

motor_bike_fanatic

New Member
Jul 26, 2011
377
2
0
Pennsylvania
Today I converted my bullet light from a 4.9v incandescent bulb to LED. The bullet light had already been modified to run the 4.9v bulb. When I got the light, it ran on one D cell battery and wasn't very bright. It was also old and neglected and needed some TLC to get it working. I swapped out the D cell battery for a battery pack that holds 4 AA batteries, wired the ground wire to the light's switch, and soldered the lead to the 4.9v bulb. It was about as bright as a 6v flashlight. I thought it was fine, for awhile. Then my wife and I moved from the country to the city, and with streetlights, it didn't do hardly anything. So I began to think about converting it to LED, but wasn't sure how I would do it. I looked for an LED bulb that I could screw in like the 4.9v bulb, but the only ones I could find on eBay were in china. Wednesday night, I took a look at an LED mini mag-lite that we have but really don't use, and wondered if I could use the bulb from the flashlight. So I set about removing the bulb from the flashlight. I unscrewed the part that houses the bulb and saw a round contact. I pried that loose with a small Flathead screwdriver. I pried loose everything else until I was left with the bulb itself, and it was attached to a small piece of green circuit board with 4 contacts that had been soldered on the underside of the circuit board. I took the bulb and the circuit board and crazy glued it to the light socket in the headlight. I put the switch back together, turned it on and touched it to one of the contacts on the circuit board....nothing. I am not experienced with electrical equipment, so I spent half the night thinking I was putting the switch together wrong. Finally I gave up for the night and went to bed. I got up and took another look at the light. Kept looking at the metal tab that runs from the socket to the headlights housing. Finally it occurred to me that the bulb itself must need to be grounded. So I found another piece of wire and tested my theory by touching the lead wire of the battery pack to one contact on the light bulb, and another piece of wire from another contact on the light bulb to the socket grounding tab, and she lit right up for me. I went to walmart and got some solder. My wife's brother in law had given me two soldering irons awhile back. I got home and soldered all the wires in place and covered everything with electrical tape. The soldering job don't look real pretty since I have never soldered anything before, but it works. This light, while maybe not as bright as some other solutions, is a lot brighter than the incandescent bulb. This light is so bright if I look at the bulb for too long I get really bad bright spots in my eyes and cant see anything for a few minutes after, lol. It works really good.
 

GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
Job well done!
The only other thing I can come up with is LED's are polarity sensitive. If you connect the battery (+) and (-) up one way you get light, hook them up backwards and you get nothing.
Soooo..... If at first attempt you get nothing, try hooking up the battery wires reversed.
 
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motor_bike_fanatic

New Member
Jul 26, 2011
377
2
0
Pennsylvania
I added a second LED bulb to my headlight today, and will be adding a third tomorrow. Found some LED flashlights at a thrift store for $2 apiece. Bought two, but ruined one bulb by heating it up to push it through the plastic part that holds the lightbulbs. at least now I have something I can use to make holes in the plastic with. Anyway, going back tomorrow to snag the last LED flashlight they had left. So far, the light reminds me of the old style scooter and moped lights. Doesnt shine real far, but its super bright and shines 180 degrees. Difference between this and the old scooter lights is they were incandescent. Other than that, pretty much the same. This light is going to be very bright. If and when I do a predator build, there should be no need to add a separate lighting system. I also have a flashing LED tail light that I "found". Wont tell you where I "found" it though. its housed in rubber or silicone so its waterproof, and flashes or shines steady, but since I use it as a tail light, I always turn it on flashing.
 

motor_bike_fanatic

New Member
Jul 26, 2011
377
2
0
Pennsylvania
Im getting another led flashlight for $2 today. 3 LEDs on 4 AA batteries will be plenty bright, especially considering that two of the bulbs are rated 1.5v and they are running on 6. this thing will be at least as bright as a decent moped/scooter headlight.