Building a Q5 Light

[infection0]

Hi all, I am building my own Q5 light (not a flashlight exactly, but all of the same principles. I originally posted these questions in the fixed lighting forum but that place gets absolutely no love.) and as this is my first electrical project, I was wondering if I could get some help over here in LEDs. All of my questions pertain to flashlights as well as fixed lighting.

Here's the shopping list:

Power Supply: 3.5v 1A DC Supply.
Emitter: CREE Q5.
Heatsink Compound: Generic DX Compound.
Heatsink: The underside of my loft bed.

With everything I know about electronics, this should work. But I don't know much. A lot of people suggest resistors with LEDs, but the power supply is guaranteed to be constant.

So, I've got 4 questions for all of you pros:
1) Will this even work?
2) What voltage of power supply should I get if I want to output 700-800mA?
3) That paint on my bedframe won't impact heatsinking too much, will it?
4) I've heard that you can control the current instead of the voltage. What kind of device to I need to do that?
5) Any other considerations for this light (maybe color temperature)? I would like a warm tint but don't know where to look.

Oh, and one more thing that actually has to do with a flashlight:

I am modding an old Luxeon I flashlight into a CREE Q5 - will I need to change the circuit or is it OK as it is?

Thanks!

 

[Jarl]

3.5V 1A means it's limited to 3.5V or 1A, whichever comes first. So it can either output 3.5V at, say, 200ma or it can output 1A at 2V. I suggest getting your LED wired up, then measuring the current. If you want to reduce the current, then drop a low value, high wattage resistor in. (<1 ohm, >2 watts)

I'd advise you scrape off the paint where you're going to mount the LED. It certainly won't help. I'd advise this rather than the current heatsink compound and this'll hold the LED onto the bed, like glue.

As for a warmer emitter, you could harvest the LED out of this or order one seperately.

For an LED it's much better to control current than voltage, as a small change in voltage can have a very big impact on current. A 4V supply and linear dropper would be the cheapest/easiest option, or a buckpuck, or any driver.

and yes, lux to cree is a straight swap as far as electronics are concerned. The reflector may not be compatible with a cree, however.

 

[infection0]

Thank you so much, i love you :twothumbs