LED lowbeam experiment
 

Recently obtained some "3 Watt" rated cheapo white leds from ebay and decided to experiment with them for automotive use.
Easy to make DRL lamps or some high beam augmentation lights but I wanted to see how hard it is to create the cutoff and the little step up in the beam to the right of the center point of the projected beam.

The opportunity came up after I put window tint on our house and I had all this mirrored tint film left over. ( that is the mirror for the LEDs ).

Three LEDs connected in series and resistor values dialed in so the group of three LEDs draw around 200mA at 12.4 (ish) volts.

(That is less than half of rated power for now. Maybe later I will crank them up a little.)

I use two of these mirror assemblies each with 3 LEDs infront of the mirrors.
(total of 6 LEDs with a 400mA draw from a resting 12V lead acid battery after the two groups are parallell connected.)

For now very ugly as I just hot glued them to a piece of styrofoam,but this is not a beauty contest.

However it is still ugly enough that I'm just going to show a beam shot to the side of the house first.

http://ecomodder.com/forum/member-3d...-12-medium.jpg


Another shot on the yard including a tree in the beam of light.
This is about 7W of power as I switched to a lithium pack with 13.3V to power it for these pictures.

http://ecomodder.com/forum/member-3d...-11-medium.jpg

Here is the test rig. The one on the right side is a single piece of curved mirrored foil formed over a round object like the side of a small bucket.
Taped down with masking tape,then a thick layer of hot glue on the back side helps it hold the curved shape after it is cut off of the side of the little bucket with a razor knife.
The beam is very wide so for the next mirror (left side) I tried three pieces of curved mirrors aiming inward as an attempt to narrow the beam and try to concentrate it better.
Also both mirror assemblies aiming inward in relation to eachother and the beam is still very wide.
http://ecomodder.com/forum/member-3d...-01-medium.jpg

Some closeup shots of the one piece mirror:
http://ecomodder.com/forum/member-3d...-02-medium.jpg

http://ecomodder.com/forum/member-3d...-05-medium.jpg

http://ecomodder.com/forum/member-3d...-06-medium.jpg

Back side:
http://ecomodder.com/forum/member-3d...-07-medium.jpg

The three piece mirror:
http://ecomodder.com/forum/member-3d...-08-medium.jpg

http://ecomodder.com/forum/member-3d...-10-medium.jpg

Viewing it head on above the cutoff line:
http://ecomodder.com/forum/member-3d...-13-medium.jpg

Below the cutoff line. (in the beam):
http://ecomodder.com/forum/member-3d...-14-medium.jpg

BTW the LEDs are facing backwards and up at the mirrors and the mirrors are projecting the beam forward.So there is no direct glare (minus imperfections) looking at it head on above the cutoff line!
The pieces of masking tape near the edges of the mirror are there to clean up the beam from stray reflections due to tiny wrinkles/damage from me cutting it off of the curvature forming bucket!
Also the hot glue has to be applied very slowly in small quantities,allowing time to cool off quickly,not letting the heat get to the mirrored foil or it is going to wrinkle the foil ever so slightly even through a layer of tape and it will project an extremely spotty image!

Barna

Not bad,
I honestly thought I'd get a laugh, but I think you may be onto something, a little more powerful and getting those reflectors right might well look like a regular low beam output.
Hat off to you.

But have to mention the obvious though, legalities?

awesome beginning.

been trying to figure this out somehow too.
thanks for getting the feet off the ground here...

Are there any LEDs out there that give off light that looks more like what you would get from regular bulbs?

Thanks! I could never get them legal. However if there was a portable optical headlamp tester and we stopped 10 cars on the road at night in my area I bet 9 would fail the low beams. When I drive at night seems like everyone's headlights are aiming at the tree tops. I put my sunshade down when I have oncoming traffic to keep from getting blinded. (almost all misadjusted!). When they are behind me, I can see the shadow of my individual hair on my headliner or sunshade. That's lighting up the sky ahead not the road. It's a shame that those are legal!


Thanks! I hope other people will try too! Also now higher Wattage LEDs are cheap too so that might worth a shot instead of the small ones I got!


oil pan 4: LEDs emit their light mostly in the forward direction and not much to the side or rear like a regular bulb. These LEDs here are already wide angle,meaning they spread light in the shape of a wide cone but it would still be pretty useless in place of a regular bulb inside an automotive headlight assembly since their light would only shine on a fraction of the mirror surface designed for the incandesent bulbs. ( I actually tried it in a spare headlamp!)

However I have 194 bulb replacement LEDs (side markers) that they made to emulate the light pattern of a regular bulb. Instead of having the typical dome/lens that we see on LEDs, these little guys had an inverted cone shape at the end of the LED. So I guess that would throw some of the light back toward the rear and around the sides instead of the typical forward direction.

Maybe a small cone shaped mirror centered in front of the LED would help?

Barna

Where did you get those 194s?

When I was talking about the LED look, I ment the color of the light, those LED pictured put off something like 6500k, are there any LEDs that put off a softer color say in the 2700-3500k range something that looks more like a standard easy on the eyes head light?

Aaah color temp... these are listed as 10000k. I have some that are same physical size but rated as 1W and they are 6000-6500k. Their color is a lot less blue. More yellowish greenish in my opinion.

The 194 replacements I picked up at a trucker store along I-75 on my way to Atlanta. They were about $8 if I remember correctly and there was two in the package. They draw 15mA each. (the incandesent 194 pulls about 280mA)

Barna

Wow 10,000k I wasn't even close. 6,500k would be an improvement.

I will keep searching for 194LEDs, not that I know they are out there. Saving a 1/4 amp each is not a bad start.

One thing you will want to keep in mind about the led blinker lights, the blinker relay relies on the current draw for the blink speed. If you ever noticed your blinkers blinking 2x faster than normal, you know you have a bulb out. With LEDs it would blink even faster. Good news is that superbrightleds.com has the LED flashers that will make them blink at the normal rate, costs a little, but isn't too bad. I think marker lights and brake lights would be no problem.

On main topic, the LED headlights look pretty good, I have kind of been throwing this idea around for a while with a cone shaped reflector and putting some sort of reflective mirror to shape the beam to how I want it for brights. I drive at night 50% of the time and very little to no traffic.

Don't forget other bulbs, lights inside, dash lights, etc.

I was considering using larger LED replacements or more of them to try and get the blinker speed some what closer to normal. Maybe throw in a few resistors too.
Its not a one for one swap on the blinker bulbs.