I don't like those 'neon' 3rd brake lights, as also used on Trail Blazers/Envoys, since it causes my Valentine One to go berzerker (same light spectrum as lazer).

I also can't stand driving behind cars with LED brake/tail/turn signals. It is almost blindingly bright on some cars. It's distracting when it's dark out, you get this bright flash in your eyes and it takes a minute to adjust. It could cause an accident...seriously...as much as aiding in avoidance. Maybe my eyes are too sensitive to sudden changes in brightness, but I relate it to a glance at the sun, you have the 'after-glow' and it hampers my vision for a few moments afterward...enough to be dangerous.
>end rant

 

Neon - or cold cathode? The latter produces a nice bright white light (which is why it makes a nice LCD backlight), but it takes a high-voltage inverter to drive the lamp ($$$), and there are also concerns over the lamp's mercury content.

A properly-designed LED lamp should outlast the life of the vehicle. The usual cause of premature failure is moisture intrusion into the housing; otherwise, improper design (too much drive current or insufficient thermal dissipation) will also wipe them out prematurely. Judging the technology by its performance in mid-90s American cars ain't exactly fair

 

Do you have any specs on the current draw of an LED cluster vs. a regular incandescent bulb? I know that obviously one LED draws a lot less power than one 1157, but my point was they use so many LEDs that the difference may not be as great as some people think.

As for their use in a headlamp, I haven't seen any automotive application comparisons. But I do recall where they were trying to design LEDs to replace spotlights (for movie soundstage lighting), and by the time they added enough LEDs and cranked up the power, they were having heat problems just like on a halogen bulb and drawing a lot of power. Which is why I said their considerable power consumption advantage will not likely be as great on high output applications. Not that it wouldn't exist, but that it wouldn't be like an order of magnitude.

 

My mom had a black on black 1998 Mark VIII LSC for 7 years. Awesome car.
I always liked that tail light design on the Mark VIII.
It wasn't just really effective, it was really cool looking too.
My guess is price and power consumption is why it didn't catch on.

Now... what about the upcoming Dodge Challenger?
Isn't that a similar form of tail light?

 

I just liked the glow of those neon tail lights on the Mark. Unless you get up close, you can't really identify a light source.

And Wilson, as mentioned, yes, the idea of having fog cutting tail lights is to keep from getting rear ended. Any intense white light from the headlights serve to do nothing but blind you. The only way to see in fog is to have something ahead of you illuminated, instead of you trying to light it up. Plus, the human eye is most sensitive to the red spectrum... which is enhanced by neon's aparent ability to be more visible in fog than other lights.

It's just with the Mark's tail lights, I'd expect it to catch on as much as LEDs did.

 

Why don't they just make all the bulbs the same type that they use in the instrument panels. My cars are 10 and 14 years old now and all the gauge lights are still working.

 

Those are LED lights.

 

I have a string of 70 LED christmas lights. The whole string is something like 5-9 watts.

 

I remember those cars...I did like that effect. Are you sure it was noen? I did a little looking into using neon lighting in an industrial vehicle applicaiton about 10 years ago and I seem to recall neon tubes and the assembly consistently reffered to as 'fragile'.

Now as to why they cut thru the fog I'd venture a guess it wasn't the bulb tech but the color of the light. Red's spectrum is different than white. Red is one of the better colors for night lighting application for numbers and letters because it doesn't dialate (sp?) your pupils, thus you can focus on it faster (i.e. BMW and Pontiac gauges). Plus, red light doesn't travel as far as white light. Ever wonder why all those military guys carry red flashlights? So I'd guess the red doesn't penetrate the fog in as much your eye can better focus and recognize it.

Yellow is another good fog light color I think. Seems I remember alot of 'fog lights' inthe '80s were yellow, including those on my Dad's '90 GP.

 

I know there was a study done with LED brake lights compare to conventional bulb tail lights. The conclusion was that the LEDs, even though a very slight advantage, light up faster and people responded faster in braking conditions compared to conventional incandescent bulbs.

 

With LED taillights now on Mazda 3s and Scion tCs, expect them to be the norm everywhere, like, well, tomorrow. People who buy old cars can now get used to $650 taillight replacement bills.

 

I tried a couple of styles of LED 1157s: some $10 cheapos, and then some $65/ea. "best in the industry" ones with 32 Ultra Bright LED's each I think, all parallel. The latter were very bright viewed from directly behind the car, but MUCH less bright viewed from off-angle. The conventional 1157's were overall a lot easier to see than the LED's. Now there are styles with LED's pointed in various directions - I would think they have a much better pattern, and would fill the taillight assembly with light better.

I switched back to the conventional ones, since my main need is for people to see the car at night from all angles and not run me over (very low homebuilt car). For normal applications the cheaper ones weren't worth it, but the $$ ones would improve visibility of the car dramatically from straight behind. They are so bright in a pretty tight beam that I am now using them as red headlights on a minibike. Current draw was around 30 mA per LED or about 1A per light as I recall. That's 12 watts in brakelight mode. But 130 bucks a set, cripes. I really needed to save some power or I wouldn't have tried them.

Has anybody found really bright ones for less, with good visibility from all angles?

 

Yup, and to take a step further, Mercedes tested taillamps that had a special lens that matched the paint of the car and disappeared as soon as the tail lights were activated. According to their results, the reaction time was cut even further. I believe I read somewhere they were bring an 'X' number to the states for further testing and demonstrations to what ever agency certifies cars for the U.S.

 

LEDs are rated at differnt viewing angles, although I haven't had to research LEDs for over a year. If you look hard enough you should find them.

 

Actually, the human eye is most sensitive to green. The eye doesn't actually see red all that well, but red LEDs are very easy to make, and it's easy to make them very bright.

With regards to the current draw of LEDs versus incadesent lamps, keep in mind that it's not just a matter of steady-state current draw, but also inrush current. With the use of semiconductors to control body lighting, that becomes a very important distinction. But getting back to the point - LEDs are much more efficient at turning electrical power into light. LED taillamps still draw a fair amount of current, but they're also typically brighter than the equivalent incadescent lamp.

As far as thermal issues are concerned, it's two different situations with LEDs and incadescents. LEDs don't generate an enormous amount of heat, but that energy must be dissipated from the LED or else bad things happen (semiconductors gets rather dysfunctional above 150C or so). It's a matter of getting the LED to survive, and not so much a problem with melted down the reflector and lens. With incadescents, the problem is much different - the bulb generates enought heat to pose a threat to the surrounding components. And that leads into a huge advantage of LEDs that has not yet been discussed here is packaging - LED lamps fit into much less volume than the equivalent incadescent. That means more room for storage, crush space, fuel tanks, or any number of other things that consumers like to see done with vehicle packaging space.