Anyone moved to LED Lighting?

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According to state and/or Federal regulations, if you're driving with a tail light with one burned out LED, do you deserve a ticket, even if you still have a lot of light?
Sometimes what appears to be redundancy actually increases the failure rate.
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On Sat, 21 Nov 2009 16:47:30 -0600, snipped-for-privacy@burditt.org (Gordon Burditt) wrote:

Probably not. I wouldn't be at all surprised if my tailights far exceed the minimum requirements, so that losing a number of elements would still leave me with more than is required. Very unlike an incandescent tail light that if it loses one lamp, goes completely dark.
I'm sure you have noticed that the tail lights on cars vary greatly in size. The DOT specifies a MINIMUM size and brightness.
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This was a legal question, not a technical one. The laws tend to be written to make it easy to write tickets. I wouldn't be at all surprised if there was a maximum of 0 dead lights regardless of whether you could get it certified if you simply removed all the dead lights. The history of single incandescent bulbs that die and leave you with no light makes it more likely that "driving with a dead tail light" is a ticketable offense with 1 dead LED and 99 working ones. This more likely comes from the state vehicle code, not the DOT which is more aiming its regulations at manufacturers, but you're still stuck with both sets of rules.
I seem to recall that there are FAA regulations that you have to have at least two independent methods of measuring <something> (I forget, this may have been altitude or airspeed) but if you add a GPS unit, you now have three methods of measuring <something>. But you can't take off unless *all* of them are working, so adding the GPS just added another point of failure.
Assume that a tail light setup was certified to be 25% more than sufficiently bright with 100 LEDs. It is likely to be ticket-worthy if there's one dead light. It may be ticket-worthy if there are 101 working LEDs and one dead one. It might be ticket-worthy if there are 101 working LEDs and no dead ones and it wasn't re-certified.
I'll ask the same question about boats, which one poster said had very strict regulations. Can you get your setup certified if you have a dead light in it (without removing the dead one)? If you got your setup certified with N lights (N is, say, around 100) with a 25% margin over minimum lighting intensity, and one of N burns out, is that acceptable without re-certification (or fixing the dead one)?

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"Gordon Burditt" wrote:

It's been a long time since I read the FARs but I can tell you this much. It's a lot more "interesting" making a anding without electrical power to the instrument panel. On a flight with my CFI years ago we were returning to SRQ (Sarasota) when a fuse blew. Then we noticed a faint smell of somethying electrical burning. There was no visible smoke and everything that doesn't need electricity worked. Strangely, the radios also worked.
In order to land at SRQ you usually approach from the North and have to fly briefly into Tampa International's airspace. Tampa's controllers get pretty busy and often tell GA pilots to stand by. That afternoon was no exception.
After a couple of minutes I called them again. Same answer.
I replied "Cessna ***** standing by with electrical failure and odor of smoke in airplane."
They took care of us really fast. We landed without incident, taxied to the shop and walked away (definition of a good landing). The A&P guy found a short, fixed it and said all was well. Next time we flew that airplane, we lost electrical power to the panel again. Shortly after that I had to stop due to health issues. I assume they finally got things straightened out.

First the cop has to see the one dead LED. Then he has to be the one moron in twenty who would ticket you for it. Of course, with my luck... :^)
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On Sun, 22 Nov 2009 00:32:33 -0600, snipped-for-privacy@burditt.org (Gordon Burditt) wrote:

As with automotive lamps, the specifications for boats do not stiplulate how many elements are in the fixture or how many are lit. All that is required to be legal is to have the minimum specified illumination, and in the case of automobile tailights, there is also a requirement of the size of surface area exposed. If you have an array of 100 LED's and 50 are not lit, you are still legal in both an automobile and a boat as long as you still meet the minimum specifications.
If there is a spec of dust on the lens of your tailight will you get a ticket?

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That's one area where automotive differs from marine. In most states there are minimum requirements for headlights, tail lights, etc. You're not required to have more than the minimum but if you add any they must all function. That said, I doubt many police will ticket anyone because one of his 30 LEDs isn't working.
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"Gordon Burditt" wrote:

That depends on the circumstances. On the NJ Turnpike most people won't even be stopped. If the driver happens to be black or brown, it's an arrest offense, including a felony stop as in, "Driver! Exit the vee-hick-al and step backward toward me with your hands in the air..." all of this at gunpoint. :^(
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They had their choice and they decided to be born that way! It's not **our** faults!

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Burditt wrote:

If the light continues to meet the specification of upper and lower limits of candela in all required directions, then there is no way to deserve a ticket. If the percentage of LEDs being failed is small, chances are fairly good that the light will meet every letter of the legal requirement.

I would agree that a multiple LED light is likely to fall short of the spec sooner than a single-LED one is. However, since red LEDs usually honestly achie 100,000 hour life expectancy (white ones generally don't), I expect a multi-LED tail/brake light to meet the spec until the light has been used a few tens of thousands of hours. More, since most of the time it will not being used at full power as a brake light.
In a Crown Vic used as a police cruiser and after that as a taxicab, lights may have to run for a few tens of thousands of hours. Otherwise, any decent brake/tail or turn signal LED light should have little trouble outlasting the car unless it gets broken in a collision that does not total the car.
- Don Klipstein ( snipped-for-privacy@misty.com)
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I just had the the center-mount stoplight in my '03 Chevy Surburban fail. Appears to be a line array of 15 leds in a moulded plastic housing. Unit is completely dark. Replacement cost is over $200 not including install labor. Less than 60K miles on the vehicle. If incandescant, replacement would be a $1.25 bulb, self installed. Bummer!
Bob King

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Haven't looked into home LED home lighting yet, but the basic problem with car taillights is that the fixture is designed for a point source and the "replacements" are anything but. An LED taillight assembly (as you can see on many cars and trucks today), designed for LEDs, works great.
Unfortunately, the "replacements" are bought by idiots looking for a kewl effect, who have no idea that they might as well just leave the wiring harness unplugged for all the good their taillights do them -- frequently the other end of the car has headlights with blue glass ('cause blue is brighter) hidden behind a smoked glass shield.
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Flashlight bulbs tend to mostly be less efficient than ones used for home lighting.
One advantage LEDs have for flashlights is that their energy energy only changes slightly (mostly improves slightly) when the batteries weaken, while incandescents greatly lose energy efficiency.
Another thing: The cost of LEDs needed to achieve an 800, 1600 or 1710 lumen light is fairly prohibitive, more so for warm white, and the amount of heatsinking needed is a tall order now to get into something the size of a regular lightbulb.
As for LED taillights: They make those. Cadillac has been using them for many years already. Some other cars are now being made with them.
An LED retrofit bulb to put into a taillight made for an incandescent is another story. It is quite a tall order to get an LED light source with the same emitter shape and size and same radiation pattern and suitable output so as to achieve the same optical results as with incandescent.
A light to serve a legally required function on a motor vehicle has to fall within both lower and upper limits of candela into a few dozen different specified directions, and must be properly certified to do so, in order to be street legal. An incandescent light with an LED retrofit bulb generally fails to achieve this, let alone be certified to do so with any particular mfr/part-number LED bulb. It is illegal to refit a legally required motor vehicle light with a bulb other than one it is certified to use.
- Don Klipstein ( snipped-for-privacy@misty.com)
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Because, overall **white** LEDs do not put out much more, if any, light than an incandescent bulb for the energy used!
LEDs are more efficient in their usage than incandescents, can be. They are directional, focusing all their output in one direction. The only produce one colour of light, efficiently and do it well. An incandescent bulb with a filter only wastes energy from heat, losing all the other colours. LED's are also quite small with intense output, making them more esily seen to the human eye (noticable). When it comes to flood illumination white LEDs are too costly to compete for the small increase, if any, efficiency.

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Cost is an obstacle, but plenty of available white LEDs are now a lot more efficient than incandescents. Efficiency like that of CFLs is now the cutting edge for available warm white ones, and cool white ones without high color rendering index now get as efficient as T8 fluorescents.
Osram recently put an 8 watt LED bulb on the market in Europe, with as much lumen output as an 8 watt CFL.
- Don Klipstein ( snipped-for-privacy@misty.com)

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As some of the articles point out LED testing may be done unfairly, is many cases. The manufactures show lumen output for bare elements and then add the reflectors, lenses and other external parts later.
The ballast in not usually included in the efficiency testing, either.
Are these the white phosphour screen based LEDs, you refer too?
As a side note our company put in hundreds of OSRAM indicator pilot lamps on electrical control panels. After 10-15 years of replacing bulbs, burnout, sock melting, changing ballast current limiters, lenses and filters, we changed them all back and retrofitted them to incandescent bulbs.
Certain colours, green especially, could not be dicerned, when illuminated, if there was any windows with sunlight entering into the buildings. If we put a similar green pilot lamp with a lime green filter in it (unlit) beside a normal green illuminated unit, no difference could be detected. When we increased the drive current, the bulbs only lasted a month or so (at a cost of about $5 per bulb). These were very tiny LED segments with about 9 elements in each bulb. The ballast resistor dropped the current from a 130vdc battery bank and was a burn hazard for humans. Inverter technology was a much better proposition but too expensive a retrofit for so many bulbs. They spent tens of thousands of dollars trying all of OSRAM's tehnologies they had availble for about 10 years and finally went back to incandecent bulbs with low current supplies (less than the LEDs) and the bulbs last about 10-15 years (or until your turn them off, after a few years of usage...LOL).
In the last few years the pilot lamps got smarter and went to a non-filtered LED holder, so the area of illumination decreased and the LED elements were now visible. This made the LEDs visible and workable but the whole thing dazzled the eyes like a Christmas tree.

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Due to someone not knowing how to implement the LEDs properly, though 15 years ago efficiency of LEDs was a lot less and maybe they could not have been implemented properly.

This problem is very easy to avoid with the green LEDs that are available nowadays, not too hard to avoid with green LEDs that have been available since about 2000-2001 or so.

Have a look at what just one modern good InGaN green LED can do with 5-10 mA now, or what one made by Nichia in 2001 can do.

Did you run controlled tests? I have heard of testing showing that most incandescents do not lose much life to cold starts. They do become unable to survive a cold start before they become unable to survive continuous operation, but not by a lot. The usual incandescent failure is from a hot thin spot in the filament, prone to temperature overshoot beyond its already-excessive temperature when a cold start is imposed upon it. This bad condition of an aging filament accelerates worse than exponentially, and an aging filament that cannot survive a cold start will kick the bucket soon no matter what.
- Don Klipstein ( snipped-for-privacy@misty.com)

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The incandescents lasted forever (well at least 4-10 years) until they were turned off.
I believe I have the supplier mixed up. It wasn't OSRAM but another supplier with similiar type name???. OMRON or something..Been awhile now. These lED indicators were all crap and we tried many different styles and many different current levels. When run at their rated current (I think about 20mA) they all went up in smoke after a few years, anyway. The main (130vdc) ballast resistors were mounted elsewhere so they weren't a problem. The problem, as I saw it were they were designed as a 24v bulb with 24vdc worth of ballast in a miniature bulb....that's a no..no and did them in from localized heat. Finally, after about 15 years of experimenting with them and different breeds, the Engineering department decided to ignore the manufacturer's advice, went back to incandescents and replace the bulbs every few years when the device was de-enrgized, basically.
As I stated, the LED units are back without any diffusion. LEDs just don't put out enough light to make them look like incandescents with diffusion and still be visible with bright lighting. The red and yellow ones were never a problem, only the green, other than being short lived.

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My experience of red, yellow and green LEDs at 20 mA, for ones characterized at 20 mA:
Red - my champion experience here so far is around 1.8 lumens at 20 mA. They appear to me to achieve about .8 lumen at 10 mA. (Nichia NSPR510CS)
Yellow - I got about .6-.7 lumen at 20 mA several years ago, likely now at least a little better. My experiece is generally 60% of red - so I expect Osram to have something delivering around a lumen at 20 mA nowadays.
Green - my champion experience so far here is 3.7-4.4 lumens at 20 mA, more than half of this at 10 mA, averaging .94 lumen at 3 mA and around .58 lumen at 1.7 mA, at which their efficiency is close to peak and much improved over that at 20 mA. Part number - Nichia NSPG520AS.
http://members.misty.com/don/led.html
- Don Klipstein ( snipped-for-privacy@misty.com)

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How can the efficiency of a white LED be higher than it's constituent LEDs? Is this due to phosphour screens used?

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Yes. The usual white LEDs have blue-emitting chips coated by a phosphor that absorbs some-most of the blue light and converts it to a yellow/yellowish broad band whose spectral content typically covers mid-green to mid-red. Some of the blue light is not absorbed but passes through the phosphor, to mix with the yellow/yellowish light so that you get white light.
Nowadays, some of these blue chips used for white LEDs are achieving around 40-50% efficiency. The most efficient white LED on the market that I am aware of, Nichia NSPWR70CSS-K1 at 20 mA, is a goodly 40% efficient even after losses of the phosphor. At 20 mA, it is supposed to typically achieve 150 lumens/watt.
- Don Klipstein ( snipped-for-privacy@misty.com)

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