UKE Mini Q40 Luxeon mod

Is this a viable host for a Luxeon, or does the plastic body create insuperable heat sink problems. Any way around this, and what is max voltage for a luxeon?

Brightnorm

I would just resistor it down to about 400ma. I've run them in a Rage mod at 400ma with no problem. If you want more light than that, I would go with a metal flashlight.

Thanks LL

Brightnorm

? 1 watt LS at 400 mah seems a bit high? Or are you refering to the 5 watt?

Oops. You're right. I forgot I have an amber in there. Better keep a white one below 350.

EH? Lux, does that mean a white LS puts out more heat than other coloured LS at the same current levels?

Originally posted by Nerd:
EH? Lux, does that mean a white LS puts out more heat than other coloured LS at the same current levels?

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<font size="2" face="Verdana, Arial">It depends which color. The heat dissipated is a function of the power. The long wavelength luxeons have lower forward voltages, so require higher current to match the same power level as the white, blue, cyan, or green. Hence, the red, red/orange, and amber are rated at 385ma as opposed to 350ma for the others.

I think UKE Q40 might not dissipate heat as good as Rage. Rage doesn't have rubberized bezel like Q40. Besides, Rage has thinner material on its bezel thus dissipate heat better as well.

Alan

Originally posted by Alan:
I think UKE Q40 might not dissipate heat as good as Rage. Rage doesn't have rubberized bezel like Q40. Besides, Rage has thinner material on its bezel thus dissipate heat better as well.

Alan

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<font size="2" face="Verdana, Arial">So, if metal, thicker is better but if non-metal thinner is better?

Brightnorm

It depends on how heat conductive the material is. I am not a good engineer so I could be very wrong

Alan

Originally posted by brightnorm:
</font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by Alan:
I think UKE Q40 might not dissipate heat as good as Rage. Rage doesn't have rubberized bezel like Q40. Besides, Rage has thinner material on its bezel thus dissipate heat better as well.

Alan

Click to expand...

<font size="2" face="Verdana, Arial">So, if metal, thicker is better but if non-metal thinner is better?

Brightnorm</font><hr /></blockquote><font size="2" face="Verdana, Arial">For metal it depends on the amount of heat to be dissipated. If it's a lot, den thicker will be better because it can be conducted quickly away from the heat source. It's the exact opposite for rubber or any other material that doesn't conduct heat well. Because if it doesn't conduct heat well den having a thick amount of it is going to stop the heat from flowing outwards more. The more you resistance you give it, the more heat trapped inside, the faster your LS dies...

There's 2 processes taking place in cooling the LED:

One is conduction from the LED to the outer surface of the flashlight. For this, more metal is better since it lowers the thermal resistance.

Then there's convection and radiational cooling at the outer surface. For this, more metal mainly adds unnecessary weight, since these depend mainly on the surface area.