Using battery power to go off the City's power grid

sirnui

... a few key things that a powerful battery/inverter system offers over the average 15A wall outlet. It’s separated from what can be a noisy grid ...

And replaces it with a potentially noisy inverter.

It can offer more dynamic power (from a large bank of capacitors?) ...

Greater than the dynamic power available from your local electric utility, which uses banks of capacitors at the substation? I don’t think so.

... it can offer a better AC sinewave (better THD) to power supplies that were designed with perfect AC sinewaves in mind.

A good power supply doesn’t require "perfect AC sinewaves."

sirnui

Any power reservoir from the susbstation needs to travel many feet and it will have to go through transformers and the house wiring and electrical outlets likely rated for 15A. The audio system is not seeing anything close to what the substation can offer for power ... I have an academic background in EE. I have a BS and MS in Computer Engineering ... Theory is nice but actually applying theory is better.

Electric power can be distributed over hundreds of miles with minimal losses.

The line feeding my house originates at the substation as a 12,470/7,200 volt wye circuit. That is a very common distribution scheme in the US, and it’s a big step up from the old delta circuit that my utility previously used. Either way, you don’t want that 7,200 VAC anywhere near your system.

My audio system uses dedicated, derated 20A lines and my utility - which is not a very good one, by the way - has no trouble delivering power on demand. If there is any doubt about your utility’s ability to deliver sufficient power, a "beast of burden test" will settle it. You would need a massive bank of batteries and capacitors to come even close to delivering the power a proper utility offers.