Cree Introduces 200 Lumen/Watt Production Power LEDs 421
ndverdo writes "Cree just announced production power LEDs reaching 200 lumen/watt. Approximately doubling the previous peak LED light efficiency, the new LEDs will require less cooling. This should enable the MK-R series to finally provide direct no-hassle replacements to popular form-factors such as MR-16 spots and incandescent lighting in general. The LEDs are sampling and it is stated that 'production quantities are available with standard lead times.'"
Candlepower Forums... (Score:5, Informative)
...seems to have the expert analysis. Some people are into flashlights so much and the LEDs that may be used in them, it's crazy what details they keep tabs on.
Post on the Cree MK-R LED at Candlepower Forums. [candlepowerforums.com]
Re:light and color quality (Score:4, Informative)
its pretty common, if not standard issue now to put a patch of phosphorous over a UV led to generate the final visible light in these high powered LED's. so its very similar to what you can expect out of a CFL (course these things measure in cm)
you do get advantages though, the starting UV is generated by a crystal and not an electric arch in a vacuum so its more "rich" and if its not half assed you dont get flicker
Re:Cooling is the issue (Score:4, Informative)
If you double the efficiency, you *more* than half the cooling needed for a given amount of light.
To give an example with some math ...
Suppose you need 2000 lumens from a 100 lumen/watt bulb. That means it takes 20 watts of power, and puts out 18 watts of heat.
Replace it with a 200 lumen/watt emitter that has the same light output, and it now needs only 10 watts of power, and only puts out 8 watts of heat.
All that said, I'm looking forward to this being available for bicycle lights. Doubling the efficiency means I can have double the light with the same sized battery pack, or the same amount of light with half the battery pack or some permutation thereof. Cooling isn't a big deal for bicycle lights until you get into the really high powered lights as the airflow is usually quite good.
you seem to misunderstand colour temperature (Score:5, Informative)
When someone talks about "X Kelvin" as a colour temperature, they mean the spectrum emitted by a black-body at that temperature, which by definition is full-spectrum.
To a first approximation the sun emits radiation at 5800K.
Re:Theoretical Maimum (Score:4, Informative)
A 90 second search revealed the following "A common choice is to choose units such that the maximum possible efficacy, 683 lm/W, corresponds to an efficiency of 100%"
http://en.wikipedia.org/wiki/Luminous_efficacy [wikipedia.org]
Re:Energy efficiency (Score:5, Informative)
If only! "An upper limit for incandescent lamp luminous efficacy (LER) is around 52 lumens per watt, the theoretical value emitted by tungsten at its melting point" (wikipedia). In fact a 40W tungsten bulb outputs 12.6 lumens/watt, up to 17.5 for a 100W bulb. Incandescent bulbs aren't even in the ballpark anymore.
As to whether some people assume all light is equal, I suppose some do. But others take it very seriously [sandia.gov]. It is not an overlooked issue.
luminous efficacy (Score:4, Informative)
Wikipedia has a list of luminous efficacies:
http://en.wikipedia.org/wiki/Luminous_efficacy [wikipedia.org]
200 lm/W seems pretty good; the theoretical limit is around 300 lm/W for LEDs, and that's about 44% overall efficiency.
Re:Theoretical Maimum (Score:5, Informative)
It's way, way, way more complex than this.
683lm/W is the maximum luminous efficacy for light, yes, but that's green light.
To reproduce in full the solar spectrum so that it is indistinguishable from white light requires you to produce a 'white' that produces light from about 400-700nm (UV to IR borders).
If you take into account flourescence and its effect on colour, perhaps 350nm is the top end.
This would take perhaps 180lm/W.
As you move from near-solar (or tungsten) identical bulbs to more limited 'whites' - you get about 250-400lm/W being the maximum.
This varies from pretty good white that you won't notice being different from actual white to something rather more limited, with just blue at 430nm or so, and greenish yellow at 560nm.
This will to a cursory glance look right, but will have truly wretched colour reproduction.
Re:Cooling is the issue (Score:5, Informative)
It depend on the quality of the bulb.
Many are listed at 10,000 (or 8,000?) on-off cycles.
Osram Dulux intelligent longlife for instance is rated at 500,000 on-off cycles.
Sure it will cost more than the very cheapest CFLs but it's 5 or so times more, not 50 times more. And that's more than my LED lights are rated at (the ones I bought it's even highly rated.)
Regarding the rating and heat I think it make total sense to at least be able to put a similar power rated light-bulb in the same fixture considering the higher efficiency. I'm not 100% sure it work like that but I can't understand why it shouldn't. Using LEDs those cooling fins get hot but then again a regular lightbulb get very hot to.
You can get CFLs usable with dimmers to. I think what people should take home with them is that you should buy the CFL which fit your needs, not just any CFL. If it's going to be on for long sure buying any may be ok. If it's going to go on and off often buy one for that, if it need to be dimmable buy one for that and if it will be sitting outside like here and may have a -20 degree C around it buy one designed for that.
Re:Cooling is the issue (Score:5, Informative)
I have Cree bulbs in my 4" recessed lights. They put out a warm color, don't make any noise, and work fine on a dimmer. I honestly can't tell the difference between them and the halogens they replaced, except they run a lot cooler. They sell them at Home Depot for about $40 each. I expect them to last at least ten years. The Cree guys know what they're doing.
Re:Cooling is the issue (Score:4, Informative)
Bought 10 CFL bulbs for my kitchen. They all died in less than a year.
dont buy cheapest chinese shit, but quality CFLs with proper soft start.
Re:Cooling is the issue (Score:4, Informative)
Cree and me (Score:5, Informative)
A year ago, I had no idea who "Cree" might be.
Then I bought one of these:
http://www.fenixlight.com/viewproduct.asp?id=151 [fenixlight.com]
It's the best pocket flashlight I have ever owned. Bright and useful on "low" power (32 Lumens) and very bright on high (105 Lumens). 500 minutes of light (over 8 hours) from a single AA cell on low, or 110 minutes on high. (I'm trusting the manufacturer's numbers here, but I can verify that it actually is bright and lasts a long time.) Anyway, that's a Cree LED, and it doesn't have the horrible bluish tint of older LEDs I have bought in the past.
More recently I bought an Ecosmart light bulb at Home Depot. "Ecosmart" is a Home Depot house brand, and uses Cree LED chips. For $10 I got a light bulb that claims to give equivalent light to a 40 Watt incandescent bulb, but seems brighter than that (I think because it's much more directional; it's in a downward-facing fixture so that's fine).
http://www.homedepot.com/h_d1/N-5yc1v/R-202188260/h_d2/ProductDisplay?catalogId=10053 [homedepot.com]
And just two days ago I got a fixture that retrofits a 6" can fixture with an LED light. I bought one with the 2700K color temperature, because I like that better than the "colder" lights (bluer, which actually have higher color temperatures). I walked into the store planning to just buy a bulb for my can light fixture, and now I'm very glad I bought the whole Ecosmart fixture. I found an LED light geek web site, and the guy bought one of these just to do a teardown; he found 5 Cree LED chips inside it. Where I live, the power company is subsidizing these lights, so I only had to pay $20 for this light. This dissipates only 9.5 Watts, yet it's very bright. I love the design: it includes three spring fingers to hold it into place, but if you rotate it the fingers collapse and stop holding it. So two decades from now when the LED stops working, it will be easy to remove.
http://www.homedepot.com/h_d1/N-5yc1v/R-202240932/h_d2/ProductDisplay?catalogId=10053 [homedepot.com]
So now I want to see Cree make some sort of flush-mount ceiling fixture. I have only found a few flush-mount LED fixtures, and they are all super expensive and I can't find the 2700 K color temperature. I did find one promising looking cheap fixture, but on eBay only and it's an import from China... I have no way to be sure of the quality, other than just buying one and trying it.
My current plans are just to install some fixtures that have air gaps for circulation, so I can use the Phillips LED bulbs (omnidirectional, not directional like the Ecosmart ones). I'm going to install one of these tomorrow and see how we like it. In case the URL doesn't work right, this is a "Project Source 2-Pack White Ceiling Flush Mount" from lowes.com.
http://www.lowes.com/pd_394606-43501-87822-01_0__?productId=3745415 [lowes.com]
Based on my experience with these lights, we are just on the cusp of these becoming mainstream and common. I've been buying these because they are subsidized, but electronics always gets cheaper over time, and within a couple of years or so LED lights should be cheap enough without subsidy that everyone starts buying them. (Even without the subsidy, they make sense long-term versus incandescent bulbs. If you have incandescent lights, consider LED rather than compact fluorescent.)
P.S. I haven't bought these, but I wish the office where I work would buy them. These are Cree replacement lights for standard fluorescent fixtures. Some companies are making LED lights that are the exact size of a T8 fluorescent bulb, with matching pins; for $60 or $80 or so each bulb, you can replace fluorescents (but you must rewire the fixture to bypass the ballas
Re:Cooling is the issue (Score:5, Informative)
CFLs are most often killed by high temperatures, not poor power. Many older light fixtures (possibly even most) are fully enclosed because they were designed for incandescent bulbs. The fixtures got very hot but not so hot as to cause a fire. The problem with CFLs is that even though they use less power and result in less heat, the ambient temperature inside a fully enclosed fixture will result in premature failure. Very few new fixtures on the market are fully enclosed for this reason.
The next most common cause of CFL failure that I've seen is CFLs being placed on dimmer switches. People don't read the warning label on the package and try to use regular CFLs with dimmer switches all the time. Don't expect those bulbs to last long.
And finally, with regards to poor power... Just as dimmer switches will cause a CFL to eventually fail, power spikes and sudden drops will have the same impact. If you wiring is bad or you have a noisy device attached to power, the cheap CFLs can die early. Had a MacPro with a bad power supply cause a hum in the lines that could be heard the next house over if you listened to the CFLs. It would only happen with drawing a significant amount of power - in my case, rendering video. Serves as a good example of how if you have premature failure then there's something that needs to be fixed - or else you are asking for other, more expensive problems.
Re:comparison (Score:5, Informative)
Re:These Cree guys are really bright. (Score:5, Informative)
Re:Cooling is the issue (Score:2, Informative)
Don't buy CFL lamps, buy CCFL (or switch to LEDs)
http://blog.pegasuslighting.com/2011/06/ccfl-vs-cfl-whats-the-difference/
Re:Cree and me (Score:4, Informative)
When i was looking into replacing a whole bunch of T12 fixtures, I liked the idea of doing LED. But just upgrading the balasts from magnetic to electronic and switching to good quality T8 tubes works out to be a way better deal. T8 bulbs already do about 90 lumens/watt for a lot less money. I also talked to a good lighting contractor who does efficiency upgrades. He said the tube retrofits don't work so well. It's better to just replace the fixtures and get LED specific fixtures. What we will hopefully get around to doing is a mixture of T12->T8 retrofits for a base lighting level, and then standard LED (PAR-20) spots to light up work areas.
Re:Cooling is the issue (Score:5, Informative)
You can get CFLs usable with dimmers to.
You need special dimmers, which cost a multiple of dimmers for incandescents. And then the cost saving of using CFL over incandescents is less than the extra cost of the dimmer.
Not anymore, now you just need dimmer aware CFLs that can deal with the clipped sine wave.
Re:Cooling is the issue (Score:2, Informative)
Re:Cooling is the issue (Score:5, Informative)
Completing one's toilet was originally getting dressed and washed and a toilet (or lavatory) was the place to do that, etc, but then the word got hijacked, in a long and glorious tradition of being unable to call a spade a shovelling device...
http://aj.hd.org/TFTC/E.html#euphemisms [hd.org]
Rgds
Damon
Re:These Cree guys are really bright. (Score:5, Informative)
Cree fixtures produce a really good color spectrum. They are pretty much the company to beat on this.
Re:I hope these don't end up as car lighting (Score:4, Informative)
There's another piece to this too. There are people in the world that will take a halogen (either projection or non-projection setup) and retrofit an HID setup in it. This causes issues:
1. The non-projection setup has no cut-off - so the light goes everywhere, which is not how good HID setups are implemented.
2. The halogen projection setups - while similar to an HID setup (I have a halogen projection setup in my car) don't have some of the additional pieces to make the HID setup functional. For instance, factory setups for my vehicle have auto-levelling lamp housings to not blind oncoming traffic. Also, the cut-off (metal in the projection path to limit light output out of the top of the lamp) is in a different spot comparing non-HID projection to HID projection.
Ultimately, if you're being blinded by HID lamps - part of it could be caused by incorrect implementation. HID light, even in a correct implementation is harsher - and those sensitive to light are probably more affected; myself included.
cost of CFL (Score:4, Informative)
There is virtually no selection of dimmable CFL, the few that exist are incredibly expensive
I think that's enough examples to show there are inexpensive dimmable CFL bulbs. However Walmart has more.
CFL sucks. We're better off with incandescent in the meantime.
I've used CFLs for more than 20 years and have not had a problem with them. That's not entirely true, I have had problems with them. In photography, photos on film show color casting with florescent bulbs, and with incandescent bulbs as well. The first CFL I bought I paid $20 for, and over the next 15 years it paid it's cost back in avoided cost. That is in energy not used and in not having to replace incandescent bulbs. I wonder if you enjoy wasting money.
Falcon