LED Headlight Conversion

[Bitsyncmaster]

I did see a quick demo somewhere on that one car with LED headlights which was rated better than the non option incandescent. I do not think that one car has multi color LEDs so someone is designing better LED headlights. I'm still waiting for the design improvements to come about. It will happen. All cars will eventually have LED headlights.

The home LED bulbs I use are not multi color LEDs. I use the 5000 k color because I do like the bright white. My kitchen LEDs which have 4 four foot LED bulbs replacing the fluorescent have a color rating of 6500 k.

I have many good LED flashlights and must admit there is something lacking in how they illuminate but still they do light up what I need to see.

[content22207_2]

Sunlight is about 5000K. But sunlight also contains all the visible wavelengths. That's how it is able to reflect back everything from bright red to deep blue.

LED's produce very narrow wavelengths. A red LED produces very little blue wavelengths, and vice versa.

A common way around this limitation is to mix a variety of LED colors in one bulb. That's how programmable RGB are possible: http://www.amazon.com/Coidak-CO801-1...1329512&sr=8-3 All you're doing is choosing which LED elements to illuminate.

Single element LED's (like high power LED's) produce only whatever wavelength their material is made of, generally bright white. Shine your LED flashlight behind a red tail light lens and you'll see the problem -- very little red light is being generated.

Bill Robertson
#5939

[content22207_2]

Flat screen TV's work the same way. There isn't a single element LED behind the screen, but rather an array of multi-color LED's.

Bill Robertson
#5939

[DMCVegas]

Flat screen TV's work the same way. There isn't a single element LED behind the screen, but rather an array of multi-color LED's.

Well now, let's slow down on this one here. Not all TVs function the same way (I don't know why we insist upon calling them "Flatscreen" to differentiate them since CRT Televisions are no longer the norm, but whatevs). You have both LED Backlit TVs, as well as LED egde lighting. Both types use LEDs in lieu of florescent blubs to generate a white light which is then in turn filtered by a LCD panel. What you're describing is an OLED display, which is more akin to the functionality of plasma. Where instead of filtering light through individual pixels, the pixels instead generate the light themselves. Which gives improved colors because you have true black on the screen. And then there is DLP still to go, but that would just take us off onto another tangent.

In other words, the comparison doesn't hold water.

As the IIHS study demonstrated, just because alternative headlights are offered on 2016 model vehicles does not mean they are effective. Only one vehicle tested had headlights rated "good". Half the vehicles tested were "marginal" or "poor".

Oh, Bill. You have no idea how happy I am that you brought this up. I knew you would, and you didn't disappoint. Thank you!

For anyone who is interested in what Bill is talking about, here's a link to the study completed by the IIHS: http://www.iihs.org/iihs/news/deskto...ed-improvement

You know what that one vehicle rated as "Good" was? It was the Toyota Prius V...which uses LED headlights. In fact, my favorite quote from the IIHS was this one: "When equipped with regular halogen lights and without high-beam assist, the Prius v earns a poor rating."

[content22207_2]

Oh, Bill. You have no idea how happy I am that you brought this up. I knew you would, and you didn't disappoint. Thank you!

Actually Bill brought the IIHS study up in Post #4, complete with a hyperlink to begin the post. Is it possible Robert doesn't bother to read other peoples' posts before posting his diatribes?

If you're going to pick and choose individual cars from the IIHS study, they rated 2016 Audi A4 with LED headlights as "marginal", and 2016 Mercedes Benz CLA with LED headlights as "poor".

Bottom line: by design, LED's produce very narrow light spectrums. Only way to get a fuller spectrum is to combine multiple LED's of different colors. Some colors, such as pink, can only be produced by coating red LED's with a white phosphor (when you get right down to it, that's how white LED's are made -- they are blue LED's with a yellow phosphor coating). Do not expect single element LED's to properly illuminate other color objects.

Bill Robertson
#5939

[DMCVegas]

Once again picking and choosing what you need in order to cobble together an argument.

As the study clearly pointed out, LED Lights are indeed able to satisfy the IIHS for their requirements of driver visibility. Halogen lights as well which you continue to tout also failed. But it's not even that they simply failed, it's that they even failed to perform as well as the LEDs. The prime example of this being the same vehicle equipped with halogens. This isn't grading on a curve, it's grading against a standard. Which as I previously pointed out all relates to the pairing of a proper light source to it's proper optics.

You've also claimed things such as how police prefer halogen because of this spectrum concern as a way to back your opposition. If you've got some recent proof of this claim about police perferences, please share it. Because I'm just not seeing it.

The IIHS says LED Headlights can be viable and safe alternatives to halogen bulbs. I'm going to have to side with them on this one over you.

And if you think my posts are too long, then stop spouting off so much incorrect and/or unverifiable statements to be corrected.

[Bitsyncmaster]

You don't need to have accurate colors to drive the car safely at night. You need to see the side of the road, the center-lines, people or animals in or near the road. Other vehicles have lights to make them very visible.

I wonder if the LED light are better or worse in the fog, rain or snow.

[Chris4099]

You don't need to have accurate colors to drive the car safely at night. You need to see the side of the road, the center-lines, people or animals in or near the road. Other vehicles have lights to make them very visible.

I've been away from my PC, but this was exactly what I was going to post. The cones in our eyes don't work well in low light, so being able to see color isn't that great to begin with. What I want with headlights is good illumination of the road ahead of me, well aimed as to not blind oncoming traffic, white light (looks sharp compared to yellow halogen) and long life. As one driving with LED headlights in two my my cars now, I can say they deliver. There's also something about the 6k color temp that really reflects well from road signs. They are significantly brighter now and much easier to read and see at a distance. I may not get accurate colors, but at least I can see more and use less power too.

Now for ultimate performance, it's still hard to beat HID projectors. Talk about illumination and distribution! I just haven't seen a good 3x5 retrofit option for them. Laser is also another cool headlight tech, but still a bit early on that unless you want to pay major $$$.

[DMCVegas]

You don't need to have accurate colors to drive the car safely at night. You need to see the side of the road, the center-lines, people or animals in or near the road. Other vehicles have lights to make them very visible.

I wonder if the LED light are better or worse in the fog, rain or snow.

It really depends upon the LED being used of course, but I would think proper warm white LEDs are probably better in bad weather conditions. This is a great example right here as to why you can't just go by the spectrum of a "white LED" since there are different types which result in different outputs:



You have two separate types of White LEDs with varying light output. However, the key thing to notice is that both intersect around the 550nm frequency within the green area of the visible light spectrum that the human eye is most sensitive to (which is why night vision is tinted green). But just as important is the sharp decline in the 450nm range. That's key because blue light is what always causes the most glare. It's also the reason why Selective Yellow is a great option for fog lights, though the drawback is about a 15% attenuation in light output because of the filtration. Proper LEDs by comparison can kill the glare more effectively and provide greater visibility with non-tinted light which results in a brighter light output.

I've been away from my PC, but this was exactly what I was going to post. The cones in our eyes don't work well in low light, so being able to see color isn't that great to begin with. What I want with headlights is good illumination of the road ahead of me, well aimed as to not blind oncoming traffic, white light (looks sharp compared to yellow halogen) and long life. As one driving with LED headlights in two my my cars now, I can say they deliver. There's also something about the 6k color temp that really reflects well from road signs. They are significantly brighter now and much easier to read and see at a distance. I may not get accurate colors, but at least I can see more and use less power too.

Now for ultimate performance, it's still hard to beat HID projectors. Talk about illumination and distribution! I just haven't seen a good 3x5 retrofit option for them. Laser is also another cool headlight tech, but still a bit early on that unless you want to pay major $$$.

OSRAM/Sylvania actually used to produce HID Retrofit kits for vehicles.

http://www.dmcnews.com/Techsection/xenons/xenons.htm

They weren't cheap ($800!) but that was because the kit contained not only the bulbs and ballast, but special optics for HID bulbs. But they discontinued the kit shortly after when the DOT made the kits illegal. Real shame too.

Lasers are nice, but I don't know how rugged they're going to be in the end since their internals are so complicated.

[Tomcio]

I see that no one has mentioned the xenon lights which are pretty common and have a CRI of around 70! I notice a slight difference in how a STOP sign looks where the red is not so saturated but I don't care. I can still see that it is a stop sign.
As to the LEDs, white LEDs can vary greatly and you can't just say they're all bad. Some cheap white LEDs have a CRI of less than 70 but some high quality power LEDs can have a CRI as high as 98. Those are generally meant to be used in projectors. So, the color reproduction depends on the LED used. Light distribution depends on how well the optics are designed.
BTW, white LEDs are not using multiple colored chips (although they might) but instead a blue chip with phosphor coating that reacts to the blue light and emits other wavelengths. As a result you see a white light.
Anyway, I will be installing LED headlights in my car. I'm looking at some high quality white LEDs with 3500 lumen output and CRI of 92 (typical). They are not cheap but they are NICE. Oh, and I will not be driving them at full power as the light output would exceed the allowed limits.
In short, choose a good quality LED and design the optics correctly and you'll have a headlight that far exceeds halogen and xenon lights.