Edit: The SOB board won't drive 3 Cree's. Magic Smoke came out.
I've asked this before and didn't get an answer. Searched some more tonight, didn't see anything definitive.
I'm building a Surefire M3 Combatlight with 3 R2 Cree's, and running it on 3 AW RCR123's (12.6 volts fresh off charger).
I bought a power supply today and have been playing around with it. I decided to see if an SOB would run 3 Crees in series, so I wired it up, set the power supply on 12.6 volts, and she works! I'm going to run it for a while tonight and see how the board does.
Wayne, I know this may sound silly, but it appears that the "Voltage In" and the "Negative" for the battery pack are labeled wrong in the diagram on the website? Far be it from me to say anything, but the hole labeled for "Voltage In" is connected to the center pad that can contact the battery.