Author Topic: New white LED claimed to be as efficient as fluorescent  (Read 3559 times)

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Ungrounded Lightning Rod

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New white LED claimed to be as efficient as fluorescent
« on: December 01, 2006, 03:21:12 AM »
Found an announcement of this among my industry junkmail at work and thought it might be of interest to the board.  Link to the press release is below.


Given the longer life of LEDs and the hazardous waste issues (real or imagined by regulators) of disposing of fluorescents, LEDs would be nicer sources.  Unfortunately, up to now the fluorescents beat LEDs on light/watt ratio.


Cree Inc. has a new white LED that they claim gives as many lumens per watt as a fluorescent.  So the crossover point has apparently been reached.


(I posted a duplicate of this under homebrew power, where I usually hang out.  I think it's applicable there due to the power consumption issue.  Would be nice if I could checkbox multiple sections rather than committing to just one.)

« Last Edit: December 01, 2006, 03:21:12 AM by (unknown) »

ADMIN

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Re: New white LED claimed to be as efficient as fl
« Reply #1 on: December 01, 2006, 11:28:27 AM »
I've also been reading about these developments in LED efficiency, and have recieved lots of email asking if my efficient lighting articles are now obsolete.


In short -- no, the articles are not obsolete. Though I'm working on some short updates. My take on the situation, after researching a whole bunch of websites and trade publications:


In summer of 2006, LED manufacturers started shipping their latest and greatest white LEDs, with efficiency figures rivaling those of compact fluorescent (CF) bulbs. These new products have not yet been incorporated into RE lighting products, but by summer of 2007 we should be seeing some products that use them. The research labs of some of these companies have also reported new LED technology that is starting to rival traditional fluorescent (FL) bulbs. These may start shipping in 2007, and might be seen in RE lighting products by 2008. All of these new white LEDs are expensive right now, but the prices can be expected to drop rapidly. It's an extremely encouraging development in high-efficiency lighting, especially for folks that live off grid.


Here's an excellent resource for keeping track of the latest and greatest in new LED technology, compiled by an expert (Don Klipstein). His FAQs and other LED information are also excellent.

http://members.misty.com/don/led.html#ln


If you are poring over manufacturer's press releases and LED datasheets looking for the most efficienct LED you can find, be sure to keep the following in mind: there are two different figures often cited for efficiency. The confusion comes from manufacturer's figures -- are they giving you lumens per watt of radiated light, or lumens per watt of power used by the LED? A high number (100 lumens per watt or over) indicates the former -- and that's not a measure of efficiency, you need to measure all the power the LED wastes as heat,too.


So, be careful when reading such press releases. There are Ebay sellers right now who are completely confusing these efficiency figures for their white LEDs. Buyer beware! In 2-3 years, though, it looks like those 100+ lumens per watt figures will be showing lumen output vs. total LED power usage, which could revolutionize the efficient lighting industry.


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« Last Edit: December 01, 2006, 11:28:27 AM by ADMIN »

ghurd

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Re: New white LED claimed to be as efficient as fl
« Reply #2 on: December 01, 2006, 11:56:30 AM »
I think it'll be a Long Time before the price is worth it.


Even at $2.50 per raw LED, it will take a lot of LEDs and money to catch up to the total output of a $20 12V CFL.  And I bet they cost more than $2.50!


It'll be long before the cost will be 'Not Ridiculous' when compared to a $1 120VAC CFL.


The extra cost could be put to more magnets or solar panels to keep up with the less efficient CFLs?

G-

« Last Edit: December 01, 2006, 11:56:30 AM by ghurd »
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terry5732

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Re: New white LED claimed to be as efficient as fl
« Reply #3 on: December 01, 2006, 09:16:37 PM »
I never quite bought the efficiency aspect as the LEDs don't produce the heat of CFLs so where would the 'wasted' energy be going? The truth is LEDs produce light with little or no heat(waste) provided they aren't overdriven.
« Last Edit: December 01, 2006, 09:16:37 PM by terry5732 »

badmoonryzn

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Re: New white LED claimed to be as efficient as fl
« Reply #4 on: December 01, 2006, 10:44:31 PM »
The link you put up does noy seem to work, or it needs a password. Anyway I couldn't get it to work. might be my brain cramping again.


Badmoon

« Last Edit: December 01, 2006, 10:44:31 PM by badmoonryzn »

badmoonryzn

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Re: New white LED claimed to be as efficient as fl
« Reply #5 on: December 01, 2006, 11:39:11 PM »
Oh yea, I found a little, made in China flashlight at $4.50, that has 14 white LEDs soldered to a nice little board and they are just as good as the ones I paid $2.50 a piece for. The nice little round 1.25 inch circuit board and the LEDs are mounted in a circle with four in the middle surrounded by a circle of ten LEDs. I have used several of these in bulbs/fixtures I made for my lighting. They work great and put out a useable amount of light. I also have a couple of flashlights that work great too as long as you put in some AAA NiMH batteries of a decent current value. I used three of the 1.4mah batteries in mine I have had mine on for two hours and it still is producing good light. I will post a current draw value on the 14 LEDs as soon as I get my meter back. They really do well. I ordered some of the LEDs from Cree and I will let you all know how they do. Cheers!

badmoon

« Last Edit: December 01, 2006, 11:39:11 PM by badmoonryzn »

radiantboy

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Re: New white LED claimed to be as efficient as fl
« Reply #6 on: December 02, 2006, 04:13:56 AM »
That was quite informative about LEDs vs. CFs, but to change the subject ever so slightly . . .


I wonder if others have noticed that some of the CFs and some LEDs that are sold don't live up to their claims of long life like they used to.  I've come across this problem (now and again) for the past few years.


But first, I should point out that back in -- on I don't remember exactly -- maybe 1995  or so, I bought my first CFs from Real Goods.  When these eventually burned out, it was almost traumatic.  I had enjoyed them for so long that it was like throwing away a family heirloom!  I don't recall if they lasted the 7 or so years that they were purported to last, but they sure lasted a long time!  I felt almost like preserving them in some sort of shrine.  


Another bad experience with CFs was when I bought some from Gaiam (then I think they were called Seventh Generation, and later Harmony).  These, oddly enough, were German made(!), which usually means anything but shoddy (or used to, anyway).  I think I bought two.  In anycase, on one of them, the glass part was loosely connected to the base when I first pulled it from its box!  Gaiam replaced it for free, however.  They were very nice and prompt about it.  (I like their toilet tissue from recycled paper, too).


In the past few years, though, the CFs I've bought at stores (rather than online at "green" businesses) have sometimes not lasted so long at all, some burning out within six months or less.  Even the projected life on the labels has dropped from 7 to 5 to 3 years on some makes.  I wish I had kept up more closely with the brand and the precise date when they were installed, and the precise date they died.  Then this wouldn't sound do darn anecdotal.
 


Maybe, however, some of this is my subjective mind, after all, as the secondary reason for buying CFs in the first place was that the incandescents I had been buying seemed to be having a shorter and shorter longevity.  Thus, at first, the CFs seemed wonderfully long-lived, but over time maybe I have gotten used to the relative superiority . . . But the thing is, I've never been one to leave lights on in areas I am not in.  I am not a waster at all, even before I installed my first solar stuff.  I actually got in a bad argument once with my girlfriend (who became an ex-girlfriend relatively quickly) about leaving lights on, and this was before my first CFs or LEDs.  


With LEDS, my first bad experience was with Jade Mountain sometime back, before the merger with Real Goods and Gaiam (but don't get me wrong, I loved Jade Mountain.  Their online catalog was much better than the consolidated version that Real Goods now has, not that I'm knocking Real Goods either.  They're still a great company.)  In that particular instance, Jade Mountain gave me the phone number of the maker.  When I talked to him, he thought I was having power surges or something. But I wasn't.  He offered to give me a refund, but in good faith I refused (being all for the good effort, even if it was fatally flawed).  In any case, not too long after that, Jade Mountain's catalog had a note that they no longer sold that particular brand of LED lights, so I guess other people had problems too with that brand.


Another recent bad purchase of an LED light was from ebay.  At least in that case, however, it was much cheaper.  And yeah, I think it was from China.  I don't think that particular LED flood type light lasted more than a couple of weeks.


The best LEDs that I've bought I've gotten from Cyberguys.com.  Theirs seem sturdier and just exude "quality" compared to the few I got on ebay (not that you can't get good deals on ebay.  I've bought some solar panels that are excellent deals).




Anyway, I hope my few bad experiences with CFs and LEDs are unique.  These have been  the exceptions and not the rule.  But I have wondered if some makers are slowly scrimping on quality or something.

« Last Edit: December 02, 2006, 04:13:56 AM by radiantboy »

badmoonryzn

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Re: New white LED claimed to be as efficient as fl
« Reply #7 on: December 02, 2006, 07:24:18 PM »
I too purchased CFs because I got tired of changing bulbs ever few weeks. I'm not sure why the incandescent bulbs died so fast, but on an average all I got was 1 to 3 months per bulb. I sampled the incoming voltage for days on the computer, but it did not deviate more than a few volts and never surged. I thought I was going to see voltages all over the place. I used the sample and hold on my Techtronics/Snap-on DVOM and sampled it again just because I could not believe what I was seeing. I figured the voltage was jumping up faster than the software for the UPS could see, but nope! I never figured out what is going on, but after running a computer repair business for 12 years I know it had something to do with the grid, as I repaired dozens of PCs that burned up from over voltages and the power company never disputed the claims.


Everything in my house is directly off the grid except the sensitive electrical units, they are protected by high quality NEC or Minute Man UPS's. I have used CFs too and they use to last for a few years, but now regardless of what brand I buy they never last for more than a year. I find it frustrating as the CFs used to be 15 to 20 bucks, but now at Wally World (Wal-Mart) they cost under 3 dollars for a 11 watt bulb. I even installed a 600 watt UPS on the front porch lights. There are four of them leading out to the shop and front driveway. That was where I had to replace the bulbs every month or so. The UPS did not change a thing, so I figure the bulbs are the culprit. I even purchased GE long life industrial bulbs that cost 7 bucks for a 75-watt bulb and it was all in vein. I am left with the fact I will be replacing bulbs often outside on the porch. I am like, radiantboy about turning off things that are not being used, all but the porch lights so people do not break their butts walking through the obstacle coarse from the driveway to the porch.


When it is cold and dark the dog does not want to get off the path far enough and sometime drops a bomb on the cement in his mad dash back into the warm house. He too needs the light on. I swear, I never figured on Lassie being such a big puss. He's great if your outside, but he hates going out by himself when it's dark, raining or cold. Geez! He comes back inside and moves the cats from in front of the wood stove and warms himself up. Once he gets situated the cats just lay on him. Oh well, I have been using LEDs for over ten years in heavy duty industrial applications of high vibration, heat, shock and whatever else a truck and truck driver can throw at it. They last and last. They only way I ever had to replace a tail light, marker light or brake light was when someone backed in to something or some one stole them. At the time the 10 markers and 12 round tail/brake lights cost about 700 dollars per truck, but they did not fail from shock or vibration. We replaced the incandescent lights at least 2 per trailer per month and one per truck. and the marker lights one or two per unit.


In the winter you could double that. I went back one year per truck and trailer and it costs 200 minimum per year on lighting. The off road trucks cost even more. I never replaced a LED unit for failure. Yea, there were a few single LEDs that failed in the lamp units but there were so many on it was not worth changing. I never did get either of the companies to tell me who made their LEDs, but they were much brighter than I could get and they drew so little current the driver could leave the markers on for a day without killing the batteries. That was a blessing itself! I can't tell you how much a year we saved on jumping dead batteries all over the USA. That alone paid for the LED lights. The tiny amount of current pulled compared to incandescent was nice on the wiring and charging units. All in all they were a godsend for the trucking industry. I am told all things added up saved $2500.00 per year. I can't verify that but I do know they did pay for themselves in a short time, just one dead battery call to a truck can cost up to 500 dollars for a jump. Yea, ouch. You can't just send a little tow truck because of the power draw of most trucks, and if it needs towed ya go to get a big tow truck. $1300 dollars or more, much much more.


Anyway, I read all of the speck sheets from Trip-lite and Grote, but their claims were a bit unbelievable. Be that as it may, my figures differed a bit, but all in all there were advantages they never thought of because no one had run these things before. We were one of ten companies in the USA testing their goods and reporting on the real world experience. I managed to get them to pay for equipping ten trucks. After that we ordered all of our trailers with the LED brake and marker lighting. I look forward to he new brighter LEDs, as my fascination with this product has always been one of a child turned loose in a toy or candy shop. J I don't know why, but I can't seem to stop coming up with ideas for these devices. As a teenager and young adult I had the things all over my room, car and self.


Oh well, I suppose it was better than drugs, however it was pretty costly in those days. My parents wondered where my money went. I use my photo light meter to check the useable light output of LEDs because the buck stops there! One has to do quite a bit of experimentation to get the same output and light diffusion as a CF or incandescent bulb. I use twenty-five to get the output of a 75 watt incandescent bulb, so I hope the new ones are much brighter. So-far I have not seen a decent way to defuse the LEDs to put out the same area coverage as a round incandescent bulb. I want to see a bulb that costs where the normal person can afford to purchase the things. I have got close, but I would like to see the tiny circuit board LED chips built in a circle or globe with a dozen or so mini LEDs. I have a few of those in white, blue and red, man they are bright and just a speck on the chip. They only pull about 7 ma, that would be less than 100 ma, WoW! I can't wait to get the new ones. J Yippy!


Badmoon

« Last Edit: December 02, 2006, 07:24:18 PM by badmoonryzn »

radiantboy

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Re: New white LED claimed to be as efficient as fl
« Reply #8 on: December 03, 2006, 04:58:33 AM »
Thanks badmoon for relating your own experiences.  



Now I know I am not imagining the shorter-lifespan phenomena with more recently manufactured CFs.  



Of course, the shorter lifepsan might (for all I know) be due to the reduction in mercury in the newer CFs that is said to have taken place.  If so, it isn't so bad a tradeoff.



But brighter LEDs are surely the answer to our woes.



By the way, while my dog isn't a puss about darkness, he sure is scared of thunder, rain, and loud noises.  Whenever he is stubborn about coming in, I know I can get him to seek refuge by shooting off a roman candle or a couple of firecrackers.  



« Last Edit: December 03, 2006, 04:58:33 AM by radiantboy »

LeissKG

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Re: New white LED claimed to be as efficient as fl
« Reply #9 on: December 07, 2006, 12:59:31 AM »
According to the data sheet the XLamp7090XR-E produces 80lm at a current of 350ma. At this current the forward voltage of the LED is 3.3V. This  means that 80lm at 3.3V x 0.35A = 1.155W electrical or 80lm / 1.155W ~ 69 lm/W. With a drive current of 700mA you get 160 lm, but need very good cooling. This gives 160lm at 3.9V x 0.70A = 2.73W electrical or 160 / 2.73 ~ 58 lm/W. The LED has an half intensity angle of 80 degrees. This is fairly wide for a LED and good for illumination. According to http://nobmob.com/node/1043 they cost ~14$ at Cutter.


Klaus Leiss

« Last Edit: December 07, 2006, 12:59:31 AM by LeissKG »

LeissKG

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Re: New white LED claimed to be as efficient as fl
« Reply #10 on: December 08, 2006, 09:31:17 AM »
Today I read an announcement from Seoul Semiconductor that claims better values. See

http://seoulsemicon.co.kr/_homepage/home_eng/product/product.asp?topCODE=1&midCODE=25

According to the data sheet the Z-Power LED (P4 series) produces 85lm at a current of 350ma. At this current the forward voltage of the LED is 3.2V. This  means that 85lm at 3.2V x 0.35A = 1.12W electrical or 85lm / 1.155W ~ 76 lm/W. A variant produces 100lm at the same current. This would be 100lm at 3.2V x 0.35A = 1.12W electrical or 100lm / 1.155W ~ 90 lm/W. The announcement talks about 100lm/W. With a drive current of 1A you get ~ 220 lm according to a curve in the datasheet. The announcement talks about 240 lm at 1 A of light. The 220lm at 3.8V x 1A = 3.80W electrical or 220 / 3.80 ~ 58 lm/W. The LED has an half intensity angle of 125 degrees.


Klaus Leiss

« Last Edit: December 08, 2006, 09:31:17 AM by LeissKG »

badmoonryzn

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Re: New white LED claimed to be as efficient as cf
« Reply #11 on: December 12, 2006, 01:00:57 AM »
Well now, I tried to buy some of the new Cree LEDs, but they did not want to sell me unless I purchased one million of the things. I contacted four of the listed suppliers and only two returned my emails. The ones who did were not very enthused. One wanted me to buy the million and the other finally decided to sell me a dozen at 10 bucks per device. I realise he just wanted me to go away.


I contacted the manufacture and complained I was not able to get any of the new LEDs and he told me I was not worth dealing with. No kidding, they just don't deal with little guys because they don't want to waist their time. He said, "I would have to agree to buy one million of the LEDs in one years time in order to get any to experiment on." I bitched and called him names and told him his mother wore army boots, and I had naked pictures of his wife, mother and grandma and was going to post them to Ebay.


I tried everything; I even tried to be nice. Ok,no, LMAO, not really. Heh Heh! Truth is, they have no interest in the small business-person, so from my perspective they are little better than the insurgents in Iraq. Small business drives the American econemy and is the most impotant venue we have. Most all of the greatest minds belong to the small business group. So #! %! I ended up getting some samples from a couple of the Chinese companies with their new LEDs and I have one that equals the output of the fourteen white flashlight LEDs. I figure this by using my old photo light meter at ten feet. Screw the paper BS. I feed them both with 15ma per diode. The new one also had a small IC chip diode that was unbelievable bright. I got three colours in the chips and one white in the standard bulb type LEDs. Man what does that tell you, the Chinese are more willing to work with us than out own countrymen???? Bad PR, Really bad PR! Ops sorry, it pisses me off.


Way cool, I have yet to check the ma, but it has run for 37 hours on three button cells. It is getting dim now, but that is very impressive. I'll post the specifications in the next day or so. So anyway, ta hell with Cree and their crap, they have no interest in the American consumer. I would like to post all of the correspondence, but the #$%^&
&^#* most likely would sue my butt for something. They really sucked!


badmoon

« Last Edit: December 12, 2006, 01:00:57 AM by badmoonryzn »

pemtek

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Re: New white LED claimed to be as efficient as cf
« Reply #12 on: December 23, 2006, 04:26:40 PM »
Hi I have samples of all the latest high efficiency LED's from Cree and Soul, the reason these two LED's have higher efficiency than the competition is that they have cross licensed their technology. Cree use Souls phosphors and Soul use Crees die.


Efficiency of an LED in lumens per watt is exactly the same measure of efficiency as used for all other forms of lighting.


The watts used is the incoming electrical power

The lumens is the total VISIBLE light output


Because we are talking about visible light efficiency we should really be using the word efficacy instead.


As far as heat coming from a 10 watt 60 lumen/watt led or a 10 watt 60 lumen/watt cfl is concerned it would be almost identical bar slight differences in content of emitted radiation at non visible wavelengths. For all intents and purposes it is quite safe to do thermal output power calcs at 100% of the input electrical power as you wont be far away!


Heat from LED's is the major problem which makes them less easy to use than expected. Not only does the heat destroy the device instantly if the die temperature gets too high but if used at higher temps for long periods of time the light output degrades faster. Another kick is that the light output decreases with increased temperature. White LED's have less of a drop with temperature than do say a yellow LED. A yellow LED will actually reduce intensity by aprox 50% over aprox 20 Celcius increase in temperature! Along with reducing intensity a yellow LED will change from almost green in colour at very low temperatures right up to almost red when very hot!  OH the joys of making signals with yellow LED's!


I have access to suppliers of most of the top manufacturers LED's if people are interested I can possibly help people if they are struggling.

« Last Edit: December 23, 2006, 04:26:40 PM by pemtek »