I have a dead 18650 charger, so I removed all the circuit board inside, solder two small switches on the top to make a small focuser controller for my JMI.
It's powered by a 18650 inside, I could even add a small rheostat inside to adjust the speed.
When I don't need to DRO control unit, for example, like for a more compact setup like visual trip, this small controller could be used.