LED light bulbs are a bad idea -- Here's why

[KurtNYC]

The government has been pushing all of us to get CFLs to replace incandescent bulbs but CFLs are not without their own environmental issues. Fluorescent lights contain mercury which winds up in landfill and ground water when they are disposed of. The lightbulbs that Thomas Edison invented (which have become the icon of "ideas") will soon be outlawed in the United States because they are only 10% efficient. So some have begun to explore LED as an option for home lighting.

People have lots of sockets for delivering power to incandescent bulbs and they want to simply have an LED-based light source that fits into those sockets. So what's wrong with that? While incandescent lights burn so hot that a toy was made which used the heat of lightbulbs to cook small cakes (the Easy Bake Oven), LEDs hate heat. LED doesn't (or shouldn't) produce much heat when operating but packing them into something the size of a light bulb and containing what little heat they do produce with a glass or plastic cover is a blatant design flaw. Basically, LED light bulbs are designed to look like incandescent bulbs and that ignores the heat issues. So in a sense, LED light bulbs are designed to fail. And they do. Many fail at 1,000 hours or less.

I have a tube light which plugs into 115v AC power. After 800 hours of operation, 20% of the LEDs were failing, another 10% were flickering and the rest were much dimmer than they had been initially. PAR lights and bulbs have similar issues. The people selling LED light bulbs know, or should know, that they are not delivering value to their customers. This is a short-sighted business practice and it may delay public acceptance of what is actually a very good technology.

The good news is that LED, when properly designed, is now a very good light source. Efficient, recyclable, low cost of operation. Low voltage (12v or 24v DC) is now used by many major companies in signage, automobile lighting and flashlights. There are 12v LED fixtures available for home use.

LED light bulbs are a little like what would have happened if the first automobiles tried to look like horses. It is a new technology which ultimately does not work in sockets designed for the old, hot technology.

[liberal N proud]

1. Do you have any data showing the failure rates?

[KurtNYC]

13. I think the DOE put out stats

let me check....

No overall stats (they don't evaluate individual products) but they say heat management is the biggest design issue:

Continuous operation at elevated temperature dramatically accelerates lumen depreciation resulting in shortened useful life. The chart below shows the light output over time (experimental data to 10,000 hours and extrapolation beyond) for two identical LEDs driven at the same current but with an 11°C difference in Tj. Estimated useful life (defined as 70% of initial lumen output) decreased from ~37,000 hours to ~16,000 hours, a 57% reduction, with the 11°C temperature increase.

http://www1.eere.energy.gov/buildings/ssl/why_thermal_mgt.html

[OKIsItJustMe]

2. "Many fail at 1,000 hours or less."

This doesn't seem right to me.

For years, I've seen LED's encased in a shell. I've never seen one which wasn't. They seem to last forever (for all practical purposes.)

[KurtNYC]

26. That picture is a through-hole LED

Usually used as an indicator light and powered by DC power. To get the kind of lightbulbs people are selling (which fail) you have to pack about 60 of those side by side and put a cheap transformer behind it. Then you get something like what is being reviewed here on Amazon by users:

http://www.amazon.com/Crane-Inc-VVD-Vivid-Light/review/product/B000EFFRHC/ref=dp_top_cm_cr_acr_txt?ie=UTF8&showViewpoints=1

I have had a dozen of these (paid much less somewhere else about 5 months ago) and only 4 are still working. They do not even come CLOSE to matching their description. DON'T WASTE YOUR MONEY!!!!! They claim they will be good for reading, but they are not. They are good for accent lighting when they work.

Another:
bought 2 of these at a very bargain price. Both failed to turn on after only a couple of weeks. LEDs are supposed to last around 100,000 hours. So, it maybe not the LEDs but the way it was manufactured. It also not very bright for such a number of LEDs in it.

[Duer 157099]

3. I'll be happy when they figure out how to use them in LCD screen

the main reason LCD monitors fail is the bulb (mercury vapor) burns out - seems like using LEDs would be a very good idea.

I'm also interested in watching how ultraviolet LEDs develop - lots of good applications for that!

[OKIsItJustMe]

4. Already done

http://www.apple.com/displays/

[cosmicone]

7. LCD monitors have no "bulb" and no mercury ... I think

you mean the CRT.

[OKIsItJustMe]

10. Typical LCD displays use mercury in their fluorescent backlights

http://electronics.howstuffworks.com/lcd3.htm

[sailor65]

16. I've been using UV LED's in manufacturing for years.

They're terrific.

[regnaD kciN]

5. Well, ANYTHING is better than CFLs...

...which are not only expensive, toxic if broken, and a pain to dispose of, but also manage to make any room using them look dingy and run-down.

I was at a motel back in December, and my first reaction upon entering the hallway was to wonder how such a fleabag could have gotten decent ratings. I then realized why I had such a negative reaction -- the hall was lit with CFLs, and thus looked dark and greenish, as if you expected to see rats and junkies lining the hall. Had it been lit with regular incandescents, I have no doubt it would have looked bright and cheery.

I once tried a CFL for our main lamp in the family room, and took it out at once -- it was not only too dark (despite being rated the same as the incandescent it replaced) but gave off this weird reddish-brown color. There's no way anyone could read by that light.

I don't know what the problems are with LEDs, but there must be SOME way they can get better results than butt-fugly CFLs!

[Kali]

19. the CFL's actually take a little while to reach full brightness

they start dim and get brighter after a minute or two. It's weird and took me a while to get used to. I like them now - sheesh a fifteen watt bulb is as bright as a 75 w incandescent - that is good enough for me to cook and read by!

[liberal N proud]

20. That is the most inconvenient part of those things

I have been hoping LED's would replace the CFL's

[OKIsItJustMe]

25. In my experience, newer CFL's come to full brightness much faster than the older ones did

(We've used them since the early 80's.)

[wtmusic]

36. Seems like the spotlight cfl's take longer to reach brightness than

the "standard" ones. I have no idea why.

[cosmicone]

6. What is connected to the sockets is a transformer

which lowers the voltage down to the LED's operating level and rectifies it (i.e. from AC to DC) to allow an LED to function. LEDs are theoretically stable for 100+ years. It is the transformers that fail.

[KurtNYC]

11. Most LED light bulbs are assembled by hand in China

the LEDs fail, the wiring fails and the transformers fail too.

[daninthemoon]

8. maybe you got one bad one. i onloy have Christmas leds so far,

but they've been working fine. I'm looking forward to more led applications.

[liberal N proud]

21. Christmas, under cabinet lighting and I have a wall sconce

that I installed in my closet. The light is the blue-white light and is a little different than normal incandescent or CFL light.

[ixion]

9. that has not been my experience with LEDs

In fact, I have an led light in my computer room that has been on non-stop for about 4 years.

Count me as a big fan of LED lighting.

[KurtNYC]

12. is it in an Edison socket?

I'm only saying that 120v AC socket-powered LEDs are a bad idea. USB powered or those using a separate transformer are fine.

[ixion]

30. ah okay... gotcha

yeah, it's USB. The other LEDs that I have are either battery or transformer.

[skids]

32. Most of the edison socket bulbs are older technology LEDs

It wasn't until last year that LEDs reached the same efficiency as CFLs. Those LEDs are only available in a very few products right now. Most of the edison socket replacements are older generation LEDs and there's no real reason to use them over CFLs. (And no, the mercury in CFLs does not bother me and should not bother you. I'd get into why, but we've beat that dead horse into a paste here on this forum and it should be easy to find those threads.)

That will change as time goes on -- the new generation of LEDs will eventually penetrate the market further. They are looking to improve heat tolerance in future generations.

In the meantime, if you want LEDs that are on par with CFLs for efficiency, and you happen to have recessed can lights in your house, well engineered products have been available for about a year now.

http://www.creelighting.com/residential.htm

Personally I can stand replacing one or two more batches of CFLs so I can skip a couple generations up on any LED bulbs I own, because I know they'll be sticking around and using power for an entire decade. However, when I get to putting my psychedelic colored lights back up for the occasional fun, LEDs simply cannot be beat for efficiency when it comes to producing colored light.

[conscious evolution]

35. Thyanks for link. nt

[OKIsItJustMe]

14. Lighting the Big Apple With L.E.D.’s

http://bits.blogs.nytimes.com/2008/08/20/lighting-the-big-apple-with-leds/

August 20, 2008, 1:45 am

Lighting the Big Apple With L.E.D.’s

By Eric A. Taub

When a small city, like Calabasas, Calif., does something innovative, like banning outdoor smoking, that’s interesting. But when a big city like New York tries something new, it’s probably time to sit up and take notice.

Which is what makes an announcement scheduled for Wednesday so interesting. The city’s Department of Transportation has contracted with the Office for Visual Interaction, a lighting design group, to install and test L.E.D. street lighting. If the tests are successful, the city’s entire stock of 300,000 street lamps could one day be replaced with L.E.D. versions.

As I discussed in a Times article last month, L.E.D. lighting has become all the rage, for a number of good reasons: power consumption is much lower than for standard bulbs; unlike compact fluorescents, no harmful chemicals are emitted when the bulbs are discarded; and L.E.D.’s can last more than 50,000 hours, obviating the need to have workers change the lights. (Insert your own bulb-changing joke here.)

The OVI contract is not just to switch the city’s current crop of high-pressure sodium lamps for L.E.D.’s, but to introduce a completely redesigned lamp pole as well. Today’s poles have become a designer’s nightmare, with signs, traffic lights, control boxes and other accessories hung willy-nilly from them. The OSI approach envisions a sleek design that includes dedicated channels to hang the various accoutrements of city life.

…

[KurtNYC]

18. They won't be using LED light bulbs

they will use properly designed (hopefully) system which address thermal management.

I didn't say LED was a bad idea -- LED in a light bulb form is a bad idea because of the heat management issues this creates.

[OKIsItJustMe]

24. You're correct

http://www.oviinc.com/projects/New_York_Streetlight/index.shtm

[Warpy]

15. LEDs are great for task lighting

I finally got an LED head lamp that gets 100 hours out of an AAA battery and it's wonderful for finding things in the back of the closet and reading and weaving during power blackouts. I honestly thought it would be something I'd hide in the bottom of a drawer but it's proving to be surprisingly useful.

However, packed into a thing that looks like a light bulb and stresses the little LEDs into failure? I don't think so.

[liberal N proud]

22. I have three LED flashlights

I threw all my old flashlights in a box. I love using the LED flashlights.

[OKIsItJustMe]

27. I'm upgrading my "MagLites" and "mini-maglites" (3 down…)

Lowes stocks LED's which replace the bulbs in these wonderful flashlights.

[OKIsItJustMe]

17. Check out the heatsink on this baby!

http://lsgc.com/products/lamps/r38/

[KurtNYC]

23. That is a 3rd generation LED PAR light

they are trying to address the heat related failures of earlier designs. But IMHO this is just another expensive bad idea.

The only decent LED downlight which uses Edison sockets which I have seen is the Cree LLF-LR6:

[GeorgeGist]

28. CFLs Responsible for Less Mercury than Incandescent Light Bulbs

Ironically, CFLs present an opportunity to prevent mercury
from entering our air, where it most affects our health. The
highest source of mercury in our air comes from burning
fossil fuels such as coal, the most common fuel used in the
U.S. to produce electricity. A CFL uses 75% less energy
than an incandescent light bulb and lasts at least 6 times
longer. A power plant will emit 10mg of mercury to produce
the electricity to run an incandescent bulb compared to only
2.4mg of mercury to run a CFL for the same time.

http://web.archive.org/web/20051103092737/http://www.nema.org/lamprecycle/epafactsheet-cfl.pdf

[wtmusic]

37. Not to mention the SO2, NOX and other crap that comes out of burning coal

Thanks for link, that's a keeper :thumbsup:

[elocs]

29. I have an under-cabinet fluorescent light behind me that has been working for 12 years now.

It's the light that I probably have on the most often and it probably cost me $10 when I bought it. Unfortunately I have probably cursed it now.

[Warpy]

33. The ceiling light in my studio will be 13 in April

It was one of the first generation of CFLs, straight tubes instead of the spiral jobs out now and it's not terribly bright. It also gives the room a slightly greenish cast.

However, it's great when I'm cleaning the fuzz off the floor after dark.

[eppur_se_muova]

31. The first automobiles did look like 'horseless carriages'.

Until the 1930's no one paid much attention to streamlining. Getting away from the 'traditional' design was a real breakthrough; new LED lamps should be able to accomplish the same sort of thing.



http://en.wikipedia.org/wiki/Chrysler_Airflow
http://www.cbsnews.com/stories/2007/05/24/sunday/main2849103.shtml
http://www.cbsnews.com/elements/2007/05/24/sunday/photoessay2846924.shtml

[conscious evolution]

34. I have sold a few dozen LED bulbs

bulbs in the last year.
So far 2 were bad out of the box but replaced by the suppler.Two more died within a couple of days.As far as I know all of the others still work.I say this because I check back with some customers for a one year punch list check and I have been asking about them.
I did have one customer who did not like the color of the light.

[excess_3]

38. input voltage, nothing to do with failures

the voltage to the LED is always transformed.

if the LED is pushed too hard, to be very brite,
reliabilty will suffer

[Nihil]

39. Not had any problem with them myself ...

Ours are the plug-in replacements for halogen lamps (240v, I think it's
a GU10 socket). Have only worn out one in my son's bedroom and it lasted
a bit longer than the halogen in the same fitting (i.e., exactly the same
usage pattern) whilst the other LED lamp in that triple fitting is still
going strong.

The only other failure I've had with them was lamp that had obviously
landed a bit heavily at one time (worked but with a cracked outer case)
but I've hung onto it in the hope that I can use it in a situation that
the shattered glass doesn't matter (e.g., on a workbench).

Sorry to hear that you've been so disappointed in them, I love both LEDs
and CFLs!
:shrug: