Good stuff! I ran on the Powerwall for the last 2 hours. The app shows your draw and I was only using 0.7 kW and lost about 4% charge an hour. That was just the fridge, home network, and stuff like DVRs, etc that were on. Not bad. Add in occasional microwave use, etc, it should get 10-15 hours of run time. A second one would be nice for sure. A second PW increases your amp draw to 60A as well, another bonus, which would allow A/C and Tesla wall connector use. I do have all LED lighting and high efficiency fridge.
Yeah, but I doubt you want to charge the car during a grid failure - power becomes precious at that point and only if you had to get ready to "evacuate in a dangerous situation" would that wall power be useful as car power. Grid outages in my area usually last a few minutes and the one outage every three years to me isn't worth the costs (would rather keep the cash growing in mutual fund, etc.) Great conversation piece and also moderate convenience if home-business is in play. The PW should talk to an HPWC and signal "I'm the power now, consider not charging the car unless owner overrides this". Otherwise, a car charging at night, then the gridfails, could drain the battery quickly if smarts aren't integrated but the HPWC is in the circuits backed up by the wall(s).
The powerwall "not" telling you that it is the source of power after a cut-over is a real lacking feature.
We bought a nat gas fed Generac for relatives who had medical conditions a year ago. Turns out the man of the couple perished a few months later but the woman still runs a business at home but moved to laptops, thus allowing a smooth fail-over should they endure the 10-second generac cutover. Costs about the same as the wall - but could run "days" should it be needed (NG amount limited to municipal feeds, so of course problems there if pumps fail).
The pricing of the wall starts to compete with the Generac solutions out there now and as such, since it doesn't require trenching and sighting outside, is more compelling for a cleaner install. Generac should consider battery solutions as another business division as well - standby power shouldn't be "required" to be fuel-based only. And batteries would not need the annual maintenance these folks charge (oil change, test runs of the engine, etc.)