>Jeff, Wouldn't locating the resistor somewhere else lower the heat load on
>the heat-sink?

TYes, but the heat from the resistor has to go somewhere, and the heatsink is a
good place for this.



>The other option often used to power LEDs is a modulated waveform.

The red LED has a current rating of 15.6 A so you can get quite a lot
of extra effective brightness by strobing the current.

The green LED is rated ar 2.3 amps so again rapidly strobing would
allow pulses more than twice the DC level.

Very likely, for short pulses, you can exceed the max current rating, but
these are so bright I prefer enhanced reliability to a bit more light.

Even if you pulse the current you will not get the Voltage across the
LEDs up to 13V. I believe that WOULD kill them rather quickly. You need a "swinging choke"
if you want to duty cycle modulate and eliminate the resistor dissipation.

I wanted simplicity, so I just used a resistor.
--
Jeff Peterson