Thanks, T. my notes above reflect a two powerwall design. For panels, it was like 3 days backup with an air conditioner, and solar roof like 1.5 days.
I 100% agree with the point of needing a system to grow into. My issue is that if I get the Rivian, my electric demand could go from 11250 kw/h to like 15,000 kw/h based upon the range of the vehicle and assumption of 12,000 miles driving. As you can see I am stoked about the product, but I am starting to get frustrated that it is supposed to get this close to production and they are not releasing any significant details (they haven't even released EPA ranges). Still support the company, but questioning if I should get it now.
Still electric is about half the price of gas, but then an 80% system would only cover like 50-60; and 54 % would only cover like 33% . . . . So I have some thinking to do. Texas was a bit of a commercial for independence, so there's that. On the other hand, I live in area where electric gets up quickly when it goes out because I am very close to a major (electric) train hub. Some places on LI still have diesel trains.
There is a relatively new rebate in NY that brings the price of a powerwall down to 6,250, which I think is like 1,000 more than a generator.
The federal Green Act, if passed, will add a new federal 30% rebate for storage (right now fed rebate is only for solar systems). That will be interesting, because at that point, a battery 'generator' will be less than a gas or natural gas one of comprable juice.
FWIW, it looks like Tesla may have dropped solar prices in October 2020.
