LEDs in tail lamps etc - colour-matched or white?

[chimpboy]

This is probably (another) stupid question but when you switch to LEDs in existing tail lamp, brake lamp, and indicator housings, is it better to go with white LEDs and let the existing lens do the colour change, or to use a red LED where the lens is red, yellow LED where the lens is yellow, etc?

I am only wondering because I had a thought that maybe the narrow frequency output of an LED loses more light when it goes through a lens than a normal incandescent would. But it is not something I have noticed being talked about. Would it matter at all? What is the best way to go?

[luxoflex]

If you are going to use LED's to replace the bulb you will get better light from white LED's as the coloured one loose intensity throught the coloured lens. I have asked the boys at OzLED and this is the advice they gave me.

[chimpboy]

Thanks!

[clm434]

White led bulbs will give off too pale a colour in existing incandescent housings. Been there and went with white for the whole brightness thing, and put simply, it looked like shit. Next time I'm going the coloured bulbs

[M1S3RY]

The LED lights that you can buy from auto shops (combo stop/tail/indicator) have coloured LED's behind coloured plastic, probably for the above reasons. I think using the white ones will look too washed out, the coloured ones are still plenty bright.

[clm434]

The LED lights that you can buy from auto shops (combo stop/tail/indicator) have coloured LED's behind coloured plastic, probably for the above reasons. I think using the white ones will look too washed out, the coloured ones are still plenty bright.

Not always.
Most led specific lamps/products (combo's, etc) have lenses made to run the clear led's behind them while still retaining the proper vivid colouring.

[squizzytaylor]

Most aftermarket LED combos etc have colored LEDs, It is simply because white LEDs are by far the most expensive to produce.
The cheaper LED combos will loose their intensity quicker than a decent quality unit, this is because the cheaper manufacturer will generally have to run the LEDs at 100% efficiency to produce good results and they do have a finite life and will degrade in brightness, a better quality unit will run at say 85% (in the case of Hella) which can equate to around 3 x the lifespan.
If retro fitting LED globes to a car tail light what is generally most important is how the LED's present in relation to the lamps reflectors, a Globe with the LEDs all facing the lens will look like shit as there is no reflection, a globe that has a decent amount of leds presenting toward or side on to the reflector will ultimately look far more intense.

Cheers
Geoff

[chimpboy]

Interesting, it seems the whole issue is more debatable than I thought.

[DamTriton]

Most aftermarket LED combos etc have colored LEDs, It is simply because white LEDs are by far the most expensive to produce.
The cheaper LED combos will loose their intensity quicker than a decent quality unit, this is because the cheaper manufacturer will generally have to run the LEDs at 100% efficiency to produce good results and they do have a finite life and will degrade in brightness, a better quality unit will run at say 85% (in the case of Hella) which can equate to around 3 x the lifespan.
If retro fitting LED globes to a car tail light what is generally most important is how the LED's present in relation to the lamps reflectors, a Globe with the LEDs all facing the lens will look like shit as there is no reflection, a globe that has a decent amount of leds presenting toward or side on to the reflector will ultimately look far more intense.

Cheers
Geoff

LEDs are good for many tens of thousand hours at the least. They can and are pulsed at several amps for milliseconds in some applications with no harm, and if the supply current is limited will run for many hours without burning out. They do not suffer from any degradation of intensity, except for the white ones.

Even the high intensity white LEDs (which actually are UV LEDs illuminating a white phosphor) will last in the order of 10000 hours before the phosphor burns away.

Gotta love ricer tech

[squizzytaylor]

Most aftermarket LED combos etc have colored LEDs, It is simply because white LEDs are by far the most expensive to produce.
The cheaper LED combos will loose their intensity quicker than a decent quality unit, this is because the cheaper manufacturer will generally have to run the LEDs at 100% efficiency to produce good results and they do have a finite life and will degrade in brightness, a better quality unit will run at say 85% (in the case of Hella) which can equate to around 3 x the lifespan.
If retro fitting LED globes to a car tail light what is generally most important is how the LED's present in relation to the lamps reflectors, a Globe with the LEDs all facing the lens will look like shit as there is no reflection, a globe that has a decent amount of leds presenting toward or side on to the reflector will ultimately look far more intense.

Cheers
Geoff

LEDs are good for many tens of thousand hours at the least. They can and are pulsed at several amps for milliseconds in some applications with no harm, and if the supply current is limited will run for many hours without burning out. They do not suffer from any degradation of intensity, except for the white ones.

Even the high intensity white LEDs (which actually are UV LEDs illuminating a white phosphor) will last in the order of 10000 hours before the phosphor burns away.

Gotta love ricer tech

To some degree this may be based on the assumption that all LED's are created equal, I deal with these products on a day to day basis (on a sales level at least) and regularly see product less than 2 years old that has lost much of its luminosity (nearly all from the lower tier suppliers and we do not have warranty denials). I wish my technical knowledge was better on the science behind the things but on an operational level there is definitely a decline in performance over a period of time with colored led's, some worse than others. We rarely ever see the same issues with the likes of Hella colored units and others containing the Cree or Seoul leds and other top end product which are white which is why I believe there to be some form of degradation/ loss of performance.
As I said, I don't fully understand the science but can only relate waht I see on an operational level.

Cheers
geoff

[chimpboy]

At this point could I conclude that brand/price matters in terms of quality, and that for a retrofit you want an LED setup that has a wider arc of light output rather than just pointing straight ahead, to get the most out of the reflector arrangement?

[stuee]

At this point could I conclude that brand/price matters in terms of quality, and that for a retrofit you want an LED setup that has a wider arc of light output rather than just pointing straight ahead, to get the most out of the reflector arrangement?

This and position of the LED's as mentioned above (delving into the large vs small spotlight thread a bit here too).

If you put a colored globe through a colored filter aren't you just filtering (either reflecting or absorbing) out particular part of the spectrum (whatever size wavelengths the colors fall into) resulting in lower amount of light?

Basic filter info here: http://en.wikipedia.org/wiki/Filter_(optics)

Hence I can't see why a white LED would put out a lower amount of light unless it was a different type of light?? This is taking me way back to year 12 physics.

[chimpboy]

If you put a colored globe through a colored filter aren't you just filtering (either reflecting or absorbing) out particular part of the spectrum (whatever size wavelengths the colors fall into) resulting in lower amount of light?

Basic filter info here: http://en.wikipedia.org/wiki/Filter_(optics)

Hence I can't see why a white LED would put out a lower amount of light unless it was a different type of light?? This is taking me way back to year 12 physics.

Well, I don't know. I always thought that old school red, green, yellow, blue etc LEDs put out a narrow range of light frequencies, as opposed to having the other colours filtered out. So on that basis I was thinking that maybe 1W of red LED equals more light than 1W of white LED that's been filtered down to red only. The second filter (the red lens on the car) would do nothing in the case of a red LED, but would eliminate some of the light from a white one.

That was my theory, but I really don't know. And it sounds like white LEDs work differently altogether anyway; the LED itself is producing invisible UV light and uses a coating to convert that into a good quality white light...?

[tweak'e]

This is probably (another) stupid question but when you switch to LEDs in existing tail lamp, brake lamp, and indicator housings, is it better to go with white LEDs and let the existing lens do the colour change, or to use a red LED where the lens is red, yellow LED where the lens is yellow, etc?

well i have red led brake/tail lights simply because the rear lenses on that vehicle are no longer completely red.
its a really good way of getting around the problem of old and faded lenses.
$10 worth of led's is better than $200+ of new rear light lenses.

[stuee]

You raise valid points on the filtering issue. I forgot about the fact that they only produce a particular color spectrum. I guess it then comes down to the energy being converted to light when comparing a colored LED and a white LED (ie current draw, voltage, and heat). IIRC they don't draw current but voltage in that they cause a voltage drop but the current going through them depends on the rest of the circuit.

From wiki on white light:

There are two primary ways of producing high intensity white-light using LEDs. One is to use individual LEDs that emit three primary colors[44] – red, green, and blue, and then mix all the colors to produce white light. The other is to use a phosphor material to convert monochromatic light from a blue or UV LED to broad-spectrum white light, much in the same way a fluorescent light bulb works.

Due to metamerism, it is possible to have quite different spectra which appear white.

I'd be interested to find out more but I'm going home for the day now so nothing for me till tomorrow.

[bazzle]

I tried white leds in some stop and tail lights (both seperate) thru red orig lenses.
The light thru the lenses was too pink, prob due to the blueish spectrum contained in the leds.

I tried red globes but even though colour was good the light output was not enough in daylight for stop lights.

Ended up using standard globes again but with LL on the end of the number. (long life) . Worked real good in a 4bee.
Got from Bursons in Vic.

Bazzle

[tweak'e]

.....
I tried red globes but even though colour was good the light output was not enough in daylight for stop lights. ..........


Bazzle

thats the problem i had with my first ones. however i upgraded them to higher power ones which work fine even in day time.
however what you have to watch is heat. high powered leds produce a fair bit of heat and the do not like getting hot. as there is little heatsink you can fit into a globe size light, there is a risk of over heating them.