Step 4: Selecting the LED's

Picture of Selecting the LED's
I am using the Philips Luxeon LED's. Currently they are the most widely available power LED's at the lowest price (about $3 for both 1-watt and 3-watt stars). the place to buy these is direct from the distributor: http://www.lumiledsfuture.com (same as http://www.futurecb.com) - everyone else sells them at a huge markup. Undoubtedly other brands will become more available in the future.

The Luxeon LED's are available in a couple of formats - the most useful is the "star" format which has the LED already attached to a small heatsink. this is far easier to work with than the bare LED.

The Luxeon LED's come in both "1 watt" and "3 watt" stars. the difference between these is actually a lot less than the names indicate and they are priced nearly the same also (about $3 each). in reality, my tests show that with a large heatsink the "1 watt" model is capable of 3 watts output, while the "3 watt" model is capable of 4 watts. the "1 watt" model is notably very conservatively rated, it is really more like a 2-watt LED. the caveat is: the LED's efficiency drops with increased power (2 watts gets you about 65% of the light output of 4 watts), and lifetime may also be reduced (they are rated at 50,000 hours though). so if you are making a light for occasional use and want maximum output for the $$$, feel free to run the LED's considerably over spec. if you want an efficient room light for long-term use, stick to 2 watts on the 1 watt model, and 3 watts on the 3 watt model.

the other important difference between the 1 watt and 3 watt stars is that the 1's have an insulated heatsink, while the 3's do not - that makes the 1's a little easier to work with since you can mount them directly to a heatsink. the 3's require using an electrically insulating film between the star and the heatsink. (see the step on heatsinks).

other options:
- do you want a spotlight or a room light? if you want a room light, get the "batwing" or "lambertian" LED's. these shine light over a wide angle (either 110 degrees or 180 degrees).
- if you want a spotlight, you can get the "Star/O" model which has a built-in lens. or you can get the regular batwing model and buy a separate lens for it which easily glues on. There are several companies making very inexpensive ($1) lenses for the Luxeon that let you make a 5, 15, or 25 degree angle spotlight. I've used these ones: L2Optics/Dialight part numbers OP-005, OP-015, OP-025, and lens holder OH-ES1 or OH-S35. Try this: direct search at Future.
- equalizing brightness/hue: the different color led's are not all equally bright at full power. the simplest light (shown in this project) uses one string of LED's in each color, so when you turn all three colors on full power, the overall hue is yellowish (*very* warm). that's because the blue led's are not as bright as the other two. so if you are building a larger light, consider using an un-equal number of strings of the different colors. if you use the Luxeon-1's, try 2 strings of blue for each string of green and red. with luxeon-3's, equalized-brightness requires using 4 strings of blue, 2 strings of green, 1 string of red. this is only important if you are mostly using this as a white/off-white lamp. if you are using it for an FX lamp, there is not much point to equalizing the brightnesses.

what I used:
I used 1-watt star LED's for my light (running them at about 2.5 watts each) because I had a bunch of them already, i'd recommend using the 3-watt stars if you are buying new ones since they cost nearly the same. i used 5 red, 5 green, 5 blue led's. part numbers:

more information: the manufacturer datasheets:
Phillips Luxeon Star LED's: http://www.luxeon.com/pdfs/DS23.PDF , http://www.luxeon.com/pdfs/DS46.PDF
L2Optics/Dialight Lenses: http://www.l2optics.com/luxeon.aspx

goldFlake3 years ago
hay man thanks for the hint of running the 1 watt overspec..
i have also sinilar led costs .3 USD here ( yes 1/3 rd of a dollar us ) in pakistan.. they say its one watt.. i tried it running at 750mA it was muchg much brifghter but was also very hot .. so i returned back to 350mA usng pot .. so i think if i attach a large number f these to a pc heatsink and attach a 12 volts (1.5 Watt) dc brushless fan it can be very bright as well as cool and give more life ? what r ur words? have u over driven it ? can u share more info ..
Briguy96 years ago
What I was saying before I deleted my own comment was:

Three Things:

1. The link http://www.lumiledsfuture.com/ is outdated, you should remove it.
2. The other link http://www.futurecb.com/ works fine, but
3. In the FutureCB link, there is a parenthesis at the end of the link, making it so you can't directly access the site from the link. You should edit the link so the parenthesis isn't messing up the link.
Briguy9 Briguy96 years ago
Oh yeah you should also replace LumiLEDsFuture with FutureElectronics.com
m.carroll6 years ago
Dan, Are the Luxeon I (or III) Stars still $3 ish? I haven't seen them at that price anywhere on the net (save for ebay which are probably knockoffs...). Might you be able to post your current distributor of choice for the Luxeons?
Looks like the two links for cheap Luxeons are dead. Has anyone found another cheap site? I've been able to find the LEDs for $6 a piece.
Blaine8 years ago
Sorry if this sounds like a dumb question but exactly what model LED are you using (model# or typical lumens and radiation pattern) from lumiledsfuture.com?