On Mon, 5 Oct 2009 10:58:38 -0700 (PDT), windcrest
wrote:

The centralized system described will be drawing several amp-hours a
day just to keep the storage battery charged and it would have no
local control to actually save transformer idle consumption when
things are switched off or unplugged.


Use a satellite system then. Instead of a central DC battery "park".

Place a "Battery Station" on each branch, and charge each only at
night, when you are on off-peak rates. Rare daytime occasions are needed
where the charging circuit needs to be on during a particular device's
load duty. Run the fridge and the Air on AC still, and run the low
consumption branches on their respective DC satellites, where the battery
capacity for that branch relates to the loading your have set up on that
branch.
Adding loads may mean increasing a given satellite's battery station
capacity and a change to the charge/run software (of course).

This is an extension of my Hot Water On Demand system for only charging
the battery packs at night during off-peak hours, which do get monitored
on industrial customers. Far more efficient than AC Burns Watts On
Demand system that uses the most expensive AC power there is...
Peak Hour Usage.

Such a system would work in a household, but it would require
acceptance and implementation across a few industries to get the maximum
possible benefit from the idea. Otherwise, it ends up being a high cost
personal hobby.