I dumped some data using the api and the internal reported capacity of all 3 combined is 41,819Wh. They sell them with a bit more capacity than advertised and I do backup only so I have minimal if any degradation.
As for how long in an outage.... that sorta varies. Air conditioner running non stop, I get about 13hrs on battery with no sun. Cool day no air conditioner or heat I get about 48 hours with no sun. Fortunately the solar helps and on days that the Air conditioner goes non stop the sun does the same. Clouds days, less sun, but less cooling needed.
If the grid went down the 1st of this month and was still down, I'd be fine no changes to what I do. If it did that the 1st of Aug.... might have to ration air conditioning or get a small unit for just the room with the tank and camp out there at night.
As for adding a generator, if you get Tesla the do not support it, but it can be done. Generac has a new system that is or will be out soon that has a dc coupled generator that charges the batteries directly. Effect is that the generator can be a lot smaller, quieter, efficient, and only run if there is not enough sun+battery.
website
www.generac.com
I have not seen any reviews of the generac solar/battery system so do not know how it stacks up against Tesla. Not in a hurry to learn either since if it turns out to be better I will be a bit miffed. It does seem that the one drawback to the generac is that I can't find anything about more than one battery compartment other than one article that says you can have 2 of them for up to 36kWh. It also looks like their system max is 18kW. If I am getting 10Kw solar I can still get another 15kW from batteries with the batteries being able to burst much higher than that.
So, low usage and want comfort of a genny in addition to the solar, generac may be better. If you have two 3ton a.c.'s, electric dryer, electric heat, and electric range and want to be able to use all of it during a short outage, lots of powerwalls.
The Generac PWRcell is a home solar battery backup system that stands apart from the competition. Find out if it's right for your home here.
www.solarreviews.com
is where I got the generac info.
Compared to Tesla Powerwall’s max peak output of 7,000 W, the PWRcell is much better.
on that article is misleading. Maxed out generac vs single powerwall using old specs, yeah, generac is better. New powerwall2 can peak output the same and powerwall2+ can peak output more. Also, it seems only 2 genearc batteries on a system but you can do 10 powerwalls if you are rolling in cash.
For the generac they also offer managment modules to turn off loads, and soft starts for airconditioners so they can start. Tesla, if you do not have enough powerwalls you get a critical loads panel for the things backed up. Otherwise, you just slap more powerwalls on to be able to run more and start larger airconditioners.
Looked up specs for powerwall2's shipping. 5.8kVA continuous with 106LRA startup surge for things like airconditioners. 3ton has about 79LRA and that is what dims your lights when one kicks on.
Also, if anyone has crazy $$$ I have heard they will install those powerpacks on residential.
Protect and grow your business faster with reliable power, reduced costs and advanced software that optimizes itself. Learn more about how Tesla Energy can help you generate and store sustainable energy for use anytime - during peak demand or grid outages.
www.tesla.com
Would run my house for a week without solar....