Run CR123 battery operated devices with any DC power source.
My Home Automation system have many battery operated devices and the power hungry ones tend to use the CR123 battery type. I got tired of replacing batteries ever too often so I made a CR123 adapter board.
The regulator I use is the 3 V version of LDL1117, but it can use any regulator with the same footprint. It can be powered from any 4-18 VDC source or from USB. In some places I wire it to a mains adapter, in other places I use a Power Bank.
In most cases it needs to be hot glued in place, or it can be fitted inside a piece of 16 mm plastic electrical tube to better fit the space of a CR123.
Contact me if you want some and have soldering skills, I have plenty of PCB’s (June 2020).