Advice needed: Getting started with Luxeons

[charliek]

I've got an itch to get started with Luxeon Star lights-
what are the Basics? What kind of current do I need to design for?
How about heatsinking? Any special driver circuits needed? Optics?

Where is a good place to buy the parts I need? What are good prices?

What are the real differences between high and low dome?


Enlighten me... (pun intended)

 

[Doug S]

[ QUOTE ]
charliek said:
I've got an itch to get started with Luxeon Star lights-
what are the Basics? What kind of current do I need to design for?
How about heatsinking? Any special driver circuits needed? Optics?

Where is a good place to buy the parts I need? What are good prices?

What are the real differences between high and low dome?


Enlighten me... (pun intended)




[/ QUOTE ]
Here is a link to a thread with a bit of info on heatsinking issues:
Thermal stuff

 

[Chop]

charliek,
An easy mod to start with would be a 3D M@g mod. Go to Elektrolumens' website. Order one of his heat sinks and one or two 1 ohm resistors. You could also get one of his Fraen optics on the holder, which makes life easier.

Go to B/S/T and get a couple of the Q3J's from Hotbeam and you're set.

This assumes that you already have a soldering iron and everything that you need to do some basic soldering. You'll also need some thermal paste. The stuff from radio shack will do.

Come to think of it, you should get two of the 1W 1 ohm resistors from Elektrolumens. That way you will have the choice of running either direct drive, one resistor, two resistors in series, or two resistors in parallel. This should cover most bases.

If you're planning on getting into modding, I would also recommend a DMM. I got a decent one from radio shack for ~$30 cause you'll want to start with at least one resistor and check to see how much current you're getting across the LED. It just so happens that my M@g 3D hums along at just under 1A when direct driven. It's nice and bright and took me about an hour.

 

[charliek]

Thanks for the lead! I'll look into it.
What is a B/S/T, and what is a Q3J ?
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If you're planning on getting into modding, I would also recommend a DMM. I got a decent one from radio shack for ~$30 cause you'll want to start with at least

[/ QUOTE ]

Quite well equipped in that area- /ubbthreads/images/graemlins/smile.gif
I've got a Weller temp controlled soldering station and a Fluke DMM... .... Sold my Oscilloscope a few years back..... but still have plenty of other stuff /ubbthreads/images/graemlins/smile.gif

 

[Steelwolf]

B/S/T is the buy, sell, trade forum on Candlepowerforums.com

Q3J is the bin number for a particular category of 1W LS. Apparently this number will let you know the Vf and spectral composition of the LS. The Vf can vary between 3.1V and 3.6V, I think, and the spectral composition can go from blue/UV tint to green to yellow. AFAIK, the Q3J has the best overall characteristics.

 

[charliek]

Many thanks!
These are the things I needed to know. /ubbthreads/images/graemlins/grin.gif

 

[Chop]

charliek,
The Q3J is a 1 watt high dome luxeon. These are popular right now because they can be had for a very good price and are very white and bright. I have not seen a bad one and have used over 8 of them. They are very consistent. Hotbeam is selling them right now in the B/S/T forum. You should get a couple if you're gonna start modding. I try to keep 3 or 4 around just in case I get an idea. As far as what Q3J means:

"Q" is the flux. The higher the letter, the brighter the light of the luxeon at a given current. (Spec is 350mA) I think the Q is good for around 40 lumens. There are "R" ranked LED's floating around, but they have been inconsistent, in my experience, in brightness and color.

The "3" (usually subject to the luxeon lottery) is the designation of the color. 1=green tint, 2=greenish/yellow tint (the R2's I've seen have been on the yellow side and one was greenish), 3=white, 4=bluish, 5=purple (just a note, but in my experience the 2's do better in outdoor situations. The warmer light just cuts through the dark like a knife)

The "J" refers to the forward voltage. In this case 3.27-3.51 volts. The higher the letter, the higher the forward voltage. The lowest I've seen in a really bright luxeon is an "H" which is 3.03 - 3.27 volts. Generally speaking, you would want an LED with a low forward voltage because they provide more runtime. If you plan to direct drive, you may want something with a higher forward voltage to reduce the chance of cooking the LED.

I have a KL1 that I modded with a Q3J and a Downboy 700 circuit. It is very bright and runs for over two hours on a single 3.7v Pila rechargeable battery. I also have the M@g 3D with Q3J that I'm running in direct drive with no resistors. I can't say how long it will last, but many people push one watters to 1A without trouble. The M@g moves around ~950mA through the LED using 3 alkaline D cells. I haven't tried Nimh and probably won't because it's my understanding that Nimh batts have lower internal resistance and will likely result in a current flow in excess of 1A. Someone correct me if I'm wrong.

 

[charliek]

The high domes have a sharper focus than the low domes right?