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We've Finally Figured Out What Makes LED Bulbs So Inefficient

Posted April 24, 2013 1:00 PM

From Popular Science - New Technology, Science News, The Future Now:

LEDs should be lighting the way to a greener future: They use 75 percent less energy and last 25 times longer than incandescent light bulbs, and they do so at a cooler temperature. But right now, we mostly use LEDs in electronics, because they have a bit of a drooping problem: at higher currents, the amount of light they produce takes a nose-dive. The efficiency droop has baffled scientists for years, but researchers at the University of California, Santa Barbara and France's École Polytechnique say they've finally solved the mystery.

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SolarEagle
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#1

Re: We've Finally Figured Out What Makes LED Bulbs So Inefficient

04/24/2013 2:42 PM

Artistic interpretation of auger recombination....

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PWSlack
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#3
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Re: We've Finally Figured Out What Makes LED Bulbs So Inefficient

04/24/2013 6:40 PM

Please don't do that.

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tcmtech
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#5
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Re: We've Finally Figured Out What Makes LED Bulbs So Inefficient

04/25/2013 12:24 PM

Some days my wife gives me headaches that create a similar effect.

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Yahlasit
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#2

Re: We've Finally Figured Out What Makes LED Bulbs So Inefficient

04/24/2013 5:29 PM

How about just more of them in parallel ?, that way you could increase the total current while keeping the current thru each branch below the point where the efficiency drops.

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redfred
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Re: We've Finally Figured Out What Makes LED Bulbs So Inefficient

04/25/2013 9:13 AM

Trouble is driving any array of non-linear devices (LED) in series or parallel will always make for uneven power loading to each device as the devices age. So as one LED grows brighter by a factor less than two for a doubling of current through that LED, the sum of the remaining LED array will dim more than the one that brightens.

I do believe that this is a problem that can be solved one day for LED lighting arrays. I suspect the solution will happen at the design of the LED device itself.

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#6
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Re: We've Finally Figured Out What Makes LED Bulbs So Inefficient

04/25/2013 12:40 PM

I just had a weird experience with LED bulbs. I bought 2 LEDs to install on the two wall sconces on either side of the bed. I also installed a remote control dimmable switch to operate the 2 sconces since the wall switch is on my wife's side of the bed and she often nods off before I do. The operation had worked fine with 2 incandescent bulbs. When I installed the LEDs it seemed to work OK until I went to shut it off. Then they would dim down but after I hit the shut off they continued to dimly glow. I waited thinking that maybe a capacitor had to discharge completely but no, they continued to glow. I unscrewed one LED and replaced it with an incandescent and tried it again. This time both went out, LED and incandescent. Other than the fact that the incandescent probably has a higher resistance due to the filament and I'm not up on the workings of an LED it did baffle me. Any ideas? Ö (supposed to represent a light bulb)

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redfred
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#7
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Re: We've Finally Figured Out What Makes LED Bulbs So Inefficient

04/25/2013 12:46 PM

My WAG is your SCR dimmer needs a lower impedance to drive to be fully turned OFF.

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SolarEagle
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Re: We've Finally Figured Out What Makes LED Bulbs So Inefficient

04/25/2013 12:57 PM

but what's the fix ? They do make these control switches for LED's....

http://www.creativelightings.com/LED-Controllers-LED-RF-Remote-Controllers-s/959.htm

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redfred
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Re: We've Finally Figured Out What Makes LED Bulbs So Inefficient

04/25/2013 1:55 PM

Yes. A dimmer that can handle an LED bulb and that will completely turn OFF does exist. It seems that it does not exist in this bedroom.

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