LumiLEDS - Wow

[wind pirate]

Don't know if anyone else has seen this stuff, but a rep did a demo of these led's at our office today. Ultra bright - 4 led's lit a 25' conference room. They range from 1 - 5 watt and wow they're competing with room lighting.

Dan B - maybe something to check out for carrying on Wondermagnet?

Here's the paper on the Luxeon Emitter

http://www.lumileds.com/pdfs/AB17.PDF

Their website is at

http://www.lumileds.com

Cool stuff - anybody heard of this product?

Wind Pirate

[DanG]

The luxeon Star V has 120 lumen output; The Luexon Star III has 65 lumen output - but to get long life and high lumen output the driving circut has to be precise.

The Luxeon "emitter" series product lacks provisions for heatsinking dissipated power, since the heatsink isn't included it sold at a cheaper price. The lumiled LED junctions are easily damaged by runaway heating - they gang many segments together so over temping will dim output as weakest junctions fail.

Their top-shelve LEDS are mounted on metal core PCB to carry heat away - MAX TEMP LED Junction Temperature 135C & Aluminum-Core PCB Temperature 70C so you'll need to provide alot more thermal mass to get it to last.

$20 for Luxeon V Star & $8.75 for Star III

http://www.lumileds.com/products/rd_order.cfm

WAY too expensive EBay link for comparison only

-- http://tinyurl.com/7xnlw --

I researched it and found compact fluorescents much cheaper & easier

[DBGenerator]

I would like to see one.  Any idea what the color temperature is??  Reason I asked is because you said they are in a board room or conference room.  Video equipment can produce some funky results with the wrong lighting.  (orange faces, hot spots, odd colors, different things like that.)

[ghurd]

The light made to power used is low for all those 'Killer LEDs'.  A good regular bulb will often out shine them for the same power.  CFLs blow them away for the power used to light made.  'Regular' LEDs are a lot more efficient than the big power LEDs.

Comparing anything to the junk LEDs at the mall store, is like comparing apples to engine blocks.

Visual (eyes) comparisions are tough.  We do not see light intensity linearly.

What 'looks twice as bright' is a lot more than twice as bright.

i.e.- 2 LEDs at 25ma are "so bright", 4 are twice as bright as 2.  But they sure don't look it!

It is a trick.  An opticial illusion.

G-

(I make part of a living selling LED stuff)

[ghurd]

Puke Green comes to mind for some of them.  Some are blue.  Some are OK.

[Tom in NH]

The lumileds are quite impressive. There are a few other high power leds available too. Check http://ledsupply.com/index.html

I have learned that the resistance of these things drops as they warm up, so current consumption creeps up the longer you run them. You have to be careful to avoid driving them too hard. They can get pretty hot.

Another problem is they are a point source of light. Therefore they cast lots of shadows. If you use arrays of regular leds, the problem is lessened somewhat. --Tom

[Psycogeek]

I have applied them here many times.

we have 2 desklamps that run 9-10 watts Max, that outshine the halogen 20w things they replaced.

they make believe that they are as efficient as florescent, and basically they do use phosphors like florescent lights do. and they make believe that they are 10x more efficent than a light bulb, but reality use of them says they are 2x more efficient.

the real efficency is when used as a point source lighting. aiming the light in the direction it is actually needed, instead of blowing it all out in some shaded lamp or blowing it all over the walls.

they originally claimed a 100,000 hour life span, then they changed to a 50,000Hr stat, which is more realistic. see because the materials that make an led, DO last for a LONG time, look at all the small indicators that have burned non stop for 10-20 YEARS, but phosphors do not last that long when triggered. so how long in REALITY they will last is really unknown.

we have burned them here for almost 2 YEARS non-stop, and the ouput is similar to a new one.

in Flashlights, the batteries in the flashlights made with them last at LEAST 5X as long, and the light out of them is much better for a flashlight, when used with the manufactures optics, its a very nice blend.

i will NEVER have a flashlight again with them stupid normal bulbs, if you dont have a primadonna led flashlight your missing out.

they do get hot, but you can totally control the output, and sync them to something, like the lamp or a aluminum strip to use as a light bar.

like at 3V they output enough light for my computer stuff (12x1w) using about 2-3w of total power.

they can be Banked, like solor cells, so you can run them off of 10.4v or 14.4 and similar.

you solor people would like the one aspect of what i did with them in the automobiles, by setting them up in 14.4 banks when the car is charging they are very bright, but when your battery is Low the current use goes way down.

i put them in the automobiles because people would sometimes leave the door open, or light on, and it would kill the battery, now the dome light (set) can be on for 2 WEEKS, and i can still start the car.  not even going to happen with the usual dome lights in cars.

they are very voltage critical.

at 3.6v they will use 350-500ma

at 3.0v they will use about 50ma

so the power (voltage or current) should be regulated.

BUT, and this is a neet trick, if you do it right, instead of loosing All light as your batteries go lower, the light just dims more.

i would think that for solar lighting they would be IDEAL if you set it up like i did, with less circuit and regulation garbage, and allow it to do what it does when there is less power available.

here are some pics of the desklamp thing

http://www.boomspeed.com/nitram/DSC00593.JPG

http://www.boomspeed.com/nitram/DSC00592.JPG

http://www.boomspeed.com/nitram/DSC00594.JPG

http://www.boomspeed.com/nitram/DSC00595.JPG

this lamp is "special" :-) it has dimmers and a sattalight for lighting other areas.

[Psycogeek]

we originally started using these things when i needed light power for a video camera. the cameras own light output connector was 20W, yet i needed 50W of light at about a 20* aim.

http://www.boomspeed.com/leds/index.html

this contraption uses a total of 20W maximum and is compared to a 2cell mag with wizz bang zenon bulbs and full batteries.

the other leds are other colors , and different blends, to achieve a match to every possible light a person could film under.

they are mostly bluish, some a bit green, and some a bit more majenta, the blue light is stark, like a piece of 97% bright HP paper, the added blue lights up white stuff faster, the color doesnt bother me, but.

the Luxeon leds now come in "warm" white

and there is also a "Lo-Moon" in a 1W that is a very nice warm color, warmer than a florescent.

the colors differ between batchs, and they also change a bit depending on how hard you drive them. if you know a lot about the batch number stuff, you can purposfully get greenish ones cheap, or bluish ones for more.

some cars, are now using a red-orange and a cyan led for thier dome lights, these 2 types have the highest output, and pairing them gets you a better spectrum.

the spectrum of the whites, even the warm whites is missing huge ammounts of the total light spectrum, it is a blue led hitting yellowish phosphors, so what do you expect. the colored leds emit a very short spectrum, good for putting out COLORED light without filtering 2/3rds of it as waste.

florescent is better, but it doesnt like to be turned on and off like a yo-yo, and it has no point source capactiy, even with the reflector recessed lighting, they waste a lot of its output.

if you have not played with these type of leds, and your running a 12v system, then your missing out.