i think so. The Arc will drain the dead 123's close to null. But actually it depends. Where the 123 come from, KL1? or other led conversion? The Arc will work better if you use the almost dead battery that you take from incandescent.
Ahh, G2 and 6P. Yup, the arc would still be able to drain plenty of juice from them /ubbthreads/images/graemlins/grin.gif
Dunno about the KL2, but i prefer KL3, more bang for the buck. /ubbthreads/images/graemlins/wink.gif
I am using 123a batteries that have been 'used up' in cameras to power my LSH-P. It is running at full brightness! /ubbthreads/images/graemlins/grin.gif
The batteries I take from unregulated incandescent SureFires seem to run, on the average, for about 10 minutes in my LS. That makes one of my Arc LSs useful for a bedside light. Batteries from my A2 don't run as long in the Arc LS. Batteries from my L4 often don't have enough to get the LS out of the moon mode.