I could not find a place that this seemed to fit. However, a post regarding a cheap Q5 light indicated two RC123s were used. I recently received a 7W Watt CREE Q5 LED Flashlight Torch Zoom ZOOMABLE 400 lumens FCQ5-01. I figured if I fried it I would not lose much. I ibnserted two CR 123s and the light worked OK.
So I wonder if a Cree Q5 will take at least 6 volts, or was I just lucky?
I wouldn't take a chance on it. The seller doesn't specifically list 6V compatibility. The other thing too is many CR123 cells are a tad higher than 3V each... that is just a nominal rating. It takes them a little while to settle down when new. So you're hitting the driver circuit with a Vin way beyond specs.
I don't know why you would want to do that when you could get some 18650 ...
a RCR123 has a typical capacity of ~ 600 mah at 3.7 V = 2.22 Wh ,
and a primary CR123 somewhere between 800 and 1500 mah at 3V (but they're also expesive , I guess somewhere between 1.5 and 3 $ each) = 3.5 Wh ( for the better ones)
you have 7 Wh with 2 primary batteries ( but you loose 5 $ once )
ooor, you could buy some 18650 like the well known Trustfire Flames - 11.7 $ for two,which have ~ 2500 mah = ~ 9 Wh (you'll also need a charger for them - 9.42 $)
bottom line , it's cheaper(in the long run) and safer ( for the flashligt) to use 18650 ;)
It was more out of curiosity than anything. Another essentially identical light came with a tube for 18650 batteries. In the one referenced there is no tube, and the 18650 is loose until the tail cap is on. I suppose one could wrap a little tape around the battery, but as long as it works I guess it is OK. Most of the time, when I use it, I will probably use 3 AAAs. The light was again out of curiosity.