I
made an adapter to use cr123a batteries instead of a 2CR5 battery in my
1992 Canon Rebel autofocus slr. The 2CR5 lasts a couple of years if you keep it
out of the camera when it has no film, if you leave it in the camera
with no film it will die in a few months. I needed a new one, and I
didn't remember it costing $10, it turns out cr123a's are now cheaper
($1.70ea online), and 2CR5s are just a holder for two cr123a cells. So I
ripped out the 2 cr123a's out of the dead battery with pliers and made
new spring contacts from thin metal. The bottom contacts are from a
broken GPS I found on Squaw Pass.
In this guy's review of a Canon Elan 7 back in the day he actually complains how cr123a's cost more than a 2CR5 .
There
are some li-ion rechargeable batteries the size of a cr123a, but
they're either too high a voltage (3.7V vs 3V) or they have 1/3 the
amp-hour capacity.
