Here is an image thay may suit you better. FYI Most cordless phones will run on 9-12vdc Check yours :-)
You have little faith in our community spirit and while the average person may not care that much, the local councils and government agencies will keep such wastage in check.
Look the race is on to secure a logical home Power supply methodology.....and from what I can see, there are two trains of thought.
1. Just add more and more power supplies, batteries and UPS 's as required and do not consolidate.
2. Consolidate home backup power around a single universal system that supplies multiple voltages.
So Graemeh where do you stand ?
Here is a thought ...
Tesla was right about AC for transmission but Edison was right about DC for usefulness...