Thread: LED Headlight
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Old 01-25-2010, 02:39 AM   #35 (permalink)
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Originally Posted by captainslug View Post
Typical automotive halogens output 1500 lumens per bulb at 55 watts.

1,000mcd = 1 candela = 1 lumen. So a 55,000mcd LED is only 55 lumens.

to get 1,500 lumens you will need 30 of those 55 lumen LEDs per headlight, but you will only get the same intensity level if you have optics to go with the array, or make the array so that the LEDs are focused to converge at an ideal distance. If you can find the datasheet for those LEDs it will tell you want the drop-off distance is for their output.

You may not be able to replace your automotive high beams with LEDs, but fog lamps or running lights are very possible.
I revisited this thread the other day and it got me thinking.

Pretty sure low beam is 55 watts, and high beam is 65 watts. The biggest difference is the aim. So if 55 watts is 1500 lumens, I would think 65 watts should be about 1773 lumens.

I looked up the ebay link on page 1 for the small LEDs and if this would work, it would be good deal. 5mm LEDs, 16000 mcd typical, 18000 mcd max. 100 for about $12. So at 16000 mcd, you would need 94 LEDs for low beam, 111 LEDs for high beam. Arrange them on a PC board into a 2 1/2" square or rectangle or round or whatever best matches your existing headlight, and add the appropriate resistors.

Get a cheap set of junkyard headlight bodies to play with. So you can use the headlight glass as the diffuser, and can put in your old headlights if needed. Cut the back off enough to be able to mount the LED board inside the back of the headlight body. Make sure you mount the board so you can aim it as needed. Seal up the back of the headlight with caulk and rubber or whatever works.

Would this work?

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