SMDs in the fog light housing, Final iteration using 90mm circles of SMD 5050 leds Options

[dangrouche]

Okay, in my continuing quest to update the incandescent bulbs in our teeners, I changed out the 35 watt bulbs to SMDs in each housing. the cost was minimal of course. I also augmented the light fog grills with "3W White LED Eagle Eye Daytime Running DRL Light Tail Backup Lamp, Stock number# 2XSKU40521" from my my favorite China vendor, Bang good.com. Cost was $5.99 for four of these eagle eyes units; I installed the other pair as daytime running lights on my other car.
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I cut out some styrofoam discs (from a take out container) and placed the assembly into the fog light lenses, added some wiring, all WITHOUT cutting any of the OEM wiring.
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check it out, one of the pics shows the driver's side bulb with the 35 watt incandescent, compared to the passenger side with the four SMDs.
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the pics are misleading. I had the camera flash off and it looks like a blaze, but in person, you see eight bright dots, of the same color as DRLs that you see on current Audis. I will try to add a better pic later.

[mikesmith]

Not really, no.

The old assembly is designed for a more or less point source (really a line) with relatively even light distribution around 360 degrees. The back half of that is then captured by the reflector and distributed forward towards the lens. By contrast, LEDs tend to have conical emission patterns, with most of the light flux close to the cone axis.

If you have a single LED (or a cluster of LEDs) in the same location as the old bulb, it will be sending most of its light directly forward towards a small portion of the lens, so the pattern will be weighted heavily towards whatever part was previously handled by the lens directly in front of the bulb. Even an LED with a wide pattern (120 degrees or so) is still only illuminating the lens from the point source, not from the reflector.

If all you want to do is present a glaring white dot to oncoming motorists, then that may be OK, but it's less effective visually than a larger illuminated area, and it certainly won't throw the same beam for the purposes of helping you see the road.

Take a look at the lenses on the JW Speaker or TruckLite LED headlights to get a feel for what purpose-designed LED optics look like. They're nothing like what you'd use with a filament bulb.