LED not that efficient.

[redpoint5]

As Jeff points out, the creation of the blue LED was crucial to developing white LEDs. Both methods of producing white light require the blue LED. Combining blue with red and green LEDs creates white light, as well as converting blue to white light using a phosphor.

My assumption is that the phosphor energy conversion involves more loss than combining red/green/blue LEDs to produce white. I would further assume phosphor is the cheaper way to manufacture the light as only 1 PN junction has to be made rather than 3. Don't have time at the moment to research these assumptions, but I'm eager to learn.

I don't see the LED going away anytime soon. What else rivals the efficiency, longevity, and cost? Adjusting intensity using PWM is very efficient.

[oil pan 4]

I am unaware of anything that could replace LED.

Heck my 250w replacement LED floods were originally $44 each they do about 65 lumens per volt-amp.

[redpoint5]

Originally Posted by oil pan 4

I am unaware of anything that could replace LED.

Heck my 250w replacement LED floods were originally $44 each they do about 65 lumens per volt-amp.

Sunday I brought out a cheap Harbor Freight dual flood light to work on the car. One of the halogen bulbs went out. What an annoying hassle. I'd pay more up front to not have to replace bulbs and save electricity.

[oil pan 4]

If you have halogen work lights do what I do and get rough service replacements.
I was replacing my 150w motion detector halogen lamp every 2 or 3 months, then I put in a 100w rough service lamp and have not changed the lamp in 3 years.
On a side note I recommend installing a timer on halogen work lights. It will save power and reduce fire hazard.

Longevity is most definitely a part of efficiency. Having something fail, having to toss it and buy a new one of something definitely effects operating cost.
For example, LEDs loose efficiency if they are ran too cold, but the cold doesn't kill them, so they last just about forever.

The only disadvantage I can think of is your led never burns out, so you keep using say 60lumen per volt amp lights even as 150+ lumen LEDs come available, because your old ones just won't die.
But it's going to be a while before high intensity high efficiency compact white LEDs are available.
To get a lot of light from an LED and have it be highly efficient the LED pretty much needs to be its own fixture, that way you can have a huge array of low power LEDs working together to make a lot of light.
The best efficiency is had when you are running less than 10ma across your PN junction.
Run more than that and quantum physics starts cutting into efficiency.

[redpoint5]

As I understand, the extended life halogens simply output less lumens per watt at the benefit of being more durable. Everything is a trade-off.

I'd just rather not mess with filament light anymore. The work light was my Dad's, so when it comes time for me to get my own, I'll go LED.

Spot lights probably should just be an array of many low power LEDs, each producing either red, green, or blue to produce the desired light output. Perhaps it would cost a bit more, but it would be efficient and long lasting.

[ASV]

RBG is the most efficient way to use LED lights but it more expensive in assembly time

would be a good DIY project you can still get high power LED by the bag
in red blue and green

I made a bunch of 12v LED rings for a friend
it was enjoyable

[redpoint5]

Back around 2003 I made this LED brake light and turn signals for the motorcycle. Previously I had replaced the license plate bulb with white LEDs, which were fairly new at the time. There were no automotive bulbs, so I crushed the glass bulb and replaced the filiment with 3 LEDs and a current limiting resistor.

Turn signal


144 LEDs, each one lightly sanded to diffuse the light


Over 300 solder connections


Running light


Brake light


License plate LEDs
[IMG][/IMG]

[Stubby79]

Nice work. Too much work for my tastes, though! I buy LED "dome light" panels in red for my 3rd brake light and such.



They come in different sizes; if one wont fit properly, I've used two smaller ones side by side instead. Very effective. (I usually go for 5050 LEDs for this purpose)

[redpoint5]

Originally Posted by Stubby79

Nice work. Too much work for my tastes, though! I buy LED "dome light" panels in red for my 3rd brake light and such.

I only did it because they didn't make LED lights for automotive use back then, and I worked a night shift that had tons of down time. The internet didn't have so much content then, so once I reached the end of it, I needed something to do.

Back in 1998 I paid $8 per white LED and converted my headlamp. I had been going on night hikes every day, and would chew through a set of AA batteries on each hike. Having no money, this was unsustainable.

[wdb]

Originally Posted by redpoint5

As I understand, the extended life halogens simply output less lumens per watt at the benefit of being more durable. Everything is a trade-off.

Rough service bulbs I'm familiar with have heartier filaments with extra support. The idea is that they can take more jostling, not that they put out less light.

I started putting CFL bulbs in my work lights years ago. They don't have to be "rough service" to withstand hard use. But they are starting to die! So are other CFLs in my house.