I bought some of the Trustfire CR123A batteries that are available on Ebay. At $1 or less per battery I figured they would be a good buy even at a little less capacity than most.
They are the same size as a Duracell. I fired up my Nitecore EC1 for a runtime test. It gave me almost the same reading on my shoebox lightbox as the Duracell, which I figure is about 250 for the TF, compared to 250 for the Duracell. Selfbuilt’s review had the runtime on a primary at over an hour on high. I sat the light by a vent and quickly forgot about it. So 23 minutes later I check the light. It is already dim. Cycling through the modes, It only gives low then medium for the other 3 modes. I go ahead and let it run, it was below low mode after 35 minutes and ran until about 45 minutes, where it gave a pulsating moonlight for a minute or two before giving up.
Basically don’t waste your time on these. They will power up just fine at first and give you full brightness, but they only have less than a fourth of the capacity of a quality cell I’d say. They have no staying power either, they’ll dim quickly. So if you are considering these, just stay away and spend a couple more $$ on something with better quality. I still have one left, maybe I’ll give it a proper test.
Oh and the wrapper comes off pretty easy. I also didn’t realize primary CR123s are bigger than a RCR 16340??