LED builds.. So confusing!

[nickz]

I am looking into moving from hotwires to led builds. My problem is everything seems confusing right now. I can easily copy someone elses work but I want to do some experimenting of my own. My problem is, I know nothing about the theories or basics of using these parts. What I am looking for is a good explanation of why certain parts are used such as downboys, etc. I understand the concept of boosting or limiting voltage and ma but applying that into a light setup still gets to me. I would love to see some builds that show how the light was put together and WHY the parts used were chosen and why they were setup in the manner they were.

At the end of this, I hope to properly be able to build a single cree mag 2c and know WHY it works. While I could likely build this light right now I would have no idea WHY it does what it does.

Any help would be greatly appreciated. I have all of the tools and skills I need at my disposal such as lathes and mills and materials for heatsinks, etc but lack the basic fundamentals of the electrical designs.

 

[modamag]

Well it take some searching but here it is.
SNII Build Tutorial
Tri-Star | Quad-Lux Build Tutorial

Although these tutorials utilized Luxeon (latest technology @ the time), the concept still very much applies to any LED.

As for the electrical aspects of it. To keep things simple.
1. You want to "normally" drive the LED near or slightly above the rated Vf (forward voltage). Just like CPU overclocking, 10-20% with sufficient heatsink will normally do the trick.

2. Since you can't easily control the input voltage from the power source (unless running off a power supply), you need some DC-DC regulator to help control the current (or voltage).

For a 2C setup and driving LED (one or more), you need yourself a boost converter to bring the 2.4V up to the LED Vf (eg 3.5V).

Examples of boost converter includes Fatman/MaxFlex/BadBoy/NextGen/Shark.

If you have any other questions feel free to ask.
Remember, the more specific your question is the easier it is for someone to answer.

Have fun,
Jonathan

 

[nickz]

Jonathan,

Thanks very much. I am going to do some serious reading tonight and try to decide on a simple single emitter build. This will get me some shop time building a heatsink which will be nice. I will post here just what I come up with as a beginner build.

 

[ryball]

After a LOT of time spend reading and ordering, I finally jumped into this last night. I built up a tri-ssc p4 setup using the GREAT instructions from the second link in modamag's post.

I ended up using:

2c mag host running 2x 18650's (will be replaced with a cut down body and AW li-ion C's)
PTS2 heatsink
3x ssc p4 stars in series
modified stock switch
shark driver set to brightest (980ma IIRC)
Arctic Alumina epoxy for the stars and the driver
24awg wire
Dean's micro plugs

I am just waiting on the IMS20mm reflectors and I'll post pics of the build.

As soon as I source the material for the postive contact plate, I am going to dump the stock switch for the tail clickie that is sitting in my tool kit and get a cut down mag body to house it all. It should be easy since I already drilled a hole in the PTS2 for the negative and have the head on mini plugs.

I am so exited about having almost completed this project. I was SO scared to flip the switch when I was done.