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LED Lighting & Energy Efficiency
- Thread starter vfx
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- Energy Environment Policy
No worries. It is very common to get it wrong... or right... depending on your angle. My mom had no intention of making the spelling of my name unique. She just didn't know how to spell it the common way, and put this on my birth certificate. I swear it was a quite unique spelling until maybe 20 years ago. And now various google searches turn up all kinds of "Darells." There was a time when I could use "darell" as my unique screen name EVERYWHERE. Those days are long gone.
These new multicolor chips are also very neat:
LEDs Magazine - Cree announces Red-Green-Blue-White multichip LED, XLamp(r) Color LED performance breakthrough
Adjust your color temp to suit!
LEDs Magazine - Cree announces Red-Green-Blue-White multichip LED, XLamp(r) Color LED performance breakthrough
Adjust your color temp to suit!
Tdave
Member
What's the theoretical maximum lumens per watt?
Also, can you elaborate on your second paragraph?
In many applications one wants to drive an LED at the max current it can handle because you basically want "max lumens per emitter" which isn't the most efficient way to drive it. If you are willing and able to accept less light output then you can give it less current and you get more lumens per watt out of it then you would driving it harder.
In flashlight applications, for instance, you can reduce light output and get much longer battery life.
He was pointing out that you could get more lumens per watt if you were not trying to get as many lumens out of an individual device.
If you can afford the space and cost of more LEDs then you are better off "under-driving" an array of them.
In flashlight applications, for instance, you can reduce light output and get much longer battery life.
He was pointing out that you could get more lumens per watt if you were not trying to get as many lumens out of an individual device.
If you can afford the space and cost of more LEDs then you are better off "under-driving" an array of them.
johnr
Member
I'm not sure that LEDs are quite ready for home lighting at this time. Today, CFLs are dirt-cheap and use 1/4 the energy of an incandescent light bulb for the same amount of light. In terms of lumens per watt, most LEDs are not even as efficient as CFLs and they cost a whole lot more. They are steadily improving, so in a few more years I'm sure they'll make sense, but at this point is there any compelling reason to replace my 22 watt CFLs with LEDs?
Two of my main hobbies are LEDs and EVs. And there are MANY parallels. This post points out some of those parallels.
No, LEDs are not perfect. They are more expensive. They are directional. They have waste heat. But what the do well, they do better than any other light source that we have. The phrase "not ready for prime time" is the one that keeps bouncing around my head - I hear it for LEDs and I hear it for EVs all the time. And just like with EVs, if nobody is willing to jump in now, the product will be much slower to improve. We have to embrace the benefits of LEDs, and design around the negatives. Retrofits are bunk. We need LED-specific fixtures to take advantage of this fantastic light source.
The reason I was compelled to replace my 22 W of CFL (after it first replaced my 75 W of incandescent) is that I'm now running about 6-10 W of LED in these locations. Will I ever save enough money or energy to pay that back? Probably not. But I'm moving the technology forward, and that helps everybody eventually. Oh... and it is my hobby, so how could I NOT?
Bicycles
Solar power
LED
Electric cars
I hold all of these in equal regard. And that's pretty much my whole list of hobbies.
johnr
Member
Darell, thanks for that reply. What you've said makes sense.
Although I don't think most people will benefit from LEDs for general lighting quite yet, I'm actually quite interested in LED technology.
I've been subscribed to LEDs Magazine for several months now, it's a great way to keep up to date on these things (it's a free subscription btw).
Here's a new 8 watt LED retrofit - that ought to be real bright!
Besthongkong - LED Module 8W Mark II PAR16 E27 Warm LED Bulb
Although I don't think most people will benefit from LEDs for general lighting quite yet, I'm actually quite interested in LED technology.
I've been subscribed to LEDs Magazine for several months now, it's a great way to keep up to date on these things (it's a free subscription btw).
Here's a new 8 watt LED retrofit - that ought to be real bright!
Besthongkong - LED Module 8W Mark II PAR16 E27 Warm LED Bulb
For those interested in LEDs, Nakamura-sensei is giving a public lecture at SLAC this Wednesday night.
http://www6.slac.stanford.edu/pdf/publiclecture_nakamura.pdf
Shuji Nakamura was basically the first guy to achieve high brightness light emission from GaN, a wide bandgap semiconductor material. So he's directly responsible for bright blue and UV LEDs, which in turn make white and multicolor LEDs possible. (Also makes the blue laser diode in your Blu-ray player possible.)
I've seen him give a few technical talks for people into semiconductor photonics before, but I think this one should be geared for a more general audience.
http://www6.slac.stanford.edu/pdf/publiclecture_nakamura.pdf
Shuji Nakamura was basically the first guy to achieve high brightness light emission from GaN, a wide bandgap semiconductor material. So he's directly responsible for bright blue and UV LEDs, which in turn make white and multicolor LEDs possible. (Also makes the blue laser diode in your Blu-ray player possible.)
I've seen him give a few technical talks for people into semiconductor photonics before, but I think this one should be geared for a more general audience.
A challenge for you: What is the brightest LED bulb with an SES (E14) thread? Any form factor ok.
I'd like to throw in a few questions too:
Are there any issues with flicker due to AC power?
I foolishly picked up an LED christmas light pack and had to switch it off as the 60Hz flicker was crazy!
Are they weather proof?
I have a dead cfl as an all-night outside light that needs replacing; seems the perfect opertunity to switch to LED. Actually, I ended up puting the above christmas lights outside around my door and they have survived a couple of christmas seasons. Now living in USA; I think there's actually some law that states you must decorate your house at Christmas. I may have answered my own question.
Should we create a table of bulbs in the TR that can be replaced?
Side lights, interior light, etc.
(Love the information in this thread)
Are there any issues with flicker due to AC power?
I foolishly picked up an LED christmas light pack and had to switch it off as the 60Hz flicker was crazy!
Are they weather proof?
I have a dead cfl as an all-night outside light that needs replacing; seems the perfect opertunity to switch to LED. Actually, I ended up puting the above christmas lights outside around my door and they have survived a couple of christmas seasons. Now living in USA; I think there's actually some law that states you must decorate your house at Christmas. I may have answered my own question.
Should we create a table of bulbs in the TR that can be replaced?
Side lights, interior light, etc.
(Love the information in this thread)
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