Running a 1 watt Luxeon from a 12v. RV battery

Alphawolf · Oct 19, 2004

Is this do-able? I assume with a big enough resistor, it should be. How much heat sinking would it need? It would be placed on a 2"X 2" aluminum plate. Is that enough heat sink?

KevinL · Oct 20, 2004

To drive it at spec 350mA, you'd need a 5 watt resistor around 25 ohms with its own separate heatsink, and a heatsink for the Luxeon. The 2x2" plate sounds adequate, get one for the resistor and one for the Luxeon.

evan9162 · Oct 20, 2004

Personally, I'd use an LM317 in current mode. You need a 3.6 ohm 1W resistor and the LM317. Use separate 2"x2" plates for the '317 and the luxeon. (The '317 will need some heatsinking by its self).

modamag · Oct 20, 2004

Re: Running a 1 watt Luxeon from a 12v. RV batter

Here are couple of links regarding Lux with 12V car batteries.

evan9162 trunk light 3x1W
andrewwynn recommended Lux kit
George80 regulated dome/map light

If you worry about cost then get George80's dome light but personally I would use an nFlex with couple Lux3 from oo2oo (<$15/each). Who cares about heat and efficiency when you got an alternator and 3000 lbs of heat sink /ubbthreads/images/graemlins/wink.gif

Running a 1 watt Luxeon from a 12v. RV battery

Alphawolf

Newly Enlightened

KevinL

Flashlight Enthusiast

evan9162

Flashlight Enthusiast

modamag

Flashlight Enthusiast

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