How about getting rid of all those batteries in various devices in the home
and connecting the battery connections to one central battery?

That is to run separate wires when wiring a home and these would carry say
12 volts DC. There would be a central large battery and battery charger like
the type used in a computer UPS.

Then at each electronic gizmo which needs a battery, use a "battery
eliminator" along with a voltage regulator to supply it with the correct
voltage. And plug this into a nearby 12 volts DC "outlet".

This could provide battery power to smoke detectors, carbon monoxide
detectors, HVAC thermostat, security system, clocks, digital thermometers,
computer UPS, phone answering machine, etc.

Then only ONE battery to worry about...

A 9 volt battery eliminator picture...
http://www.wirelessmicrocolorcam.com... 7a77410624ea