Phaserburn,
I do use them, quite extensively, too... They're quite awesome...
(*note: keep in mind that Copia and Pila have the same A designation for the slightly larger diameter 18xxx sized cells and the B or S designation for the smaller 17xxx sized cells)
I use 1x 168B in my E2e to power the KL1, the MNO3 bulb, or I sometimes put a McLux head onto it. The McLux head uses a BB400Q3L... I can also use it in my 2X123 McLux body as well... Do not use it for the MN02 or MN01... I haven't tested it out with the MN02 yet, but my MN01 flashed on me, so be warned.
I use 2x 150Bs to direct drive my Space Needle and Space Needle II... It is equivalent to the size of 3xCR123s, and it will power a 9P sufficiently (P9x bulbs can be driven with it). I have used it to power (or underpower, actually, my C3, and it works fine, albeit a little dimmer than with 3xCR123s...
Pila doesn't offer a battery size that would replace only 1 CR123... It's only in the combination of 2xCR123s (1x168-size) or 3xCR123s (2x150-size)...
And you have to be careful about putting more voltage into a bulb, as it could flash the bulb... Undervoltage is fine, as I can underdrive my MN03 with a 168B, but I wouldn't put a 7.2V (2x150Bs) battery pack into a 6V bulb...
Lets just say if I really wanted to, I can actually refrain from ever buying CR123s again... Only reason why I still do, and still keep them handy is because of convenience and the occasional camping trip or trip away from a wall socket... Plus, if you drain these guys too low, they can immediately cut off their current to your lights (internal damage prevention)...
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