Looking at the Generac specs. Have to dive in them for a while, but two can be bundled together with 6 batteries in each to produce 36kWh. Interesting that they offer them with either Nickel Manganese Cobalt batteries or with Lithium Nickel Manganese Cobalt batteries. Or that's perhaps a typo.
Of course each module weighs 459# with 6 batteries in it.
Installers much just love that.
That is the first one that I've seen that can scale up that high, outside of Tesla Powerwalls.
I wonder what the comparable costs are...
Plus I just looked at my average energy usage. Over the last 3 years I used an average of 110kWh of energy per day. Ah, South Florida... So assuming that my panels produce the average of 125 kWh per day (which they did over the past 3 years), how would this work at night if I wanted the panels to power the house during sunlight as well as charge the batteries, and discharge at night feeding the house and potentially needing no energy from the grid.
Could the Generac or Tesla do that? I really don't know the energy usage day vs night in my house, but lets assume it's 60% daytime, and 40% nighttime. So I would need 44 kWh of battery capacity (somewhat more, considering they won't totally discharge) to totally power the house at night. I'm not aware of any battery system that can do that. The Generac comes close, and on winter days would easily accomplish this. But on those hot summer Florida days - no way.
And as far as charging the batteries fully during sunlight and power the house. I would need 66kWh of solar production to cover daytime electricity usage and an additional 44kWh of solar production to charge the batteries for nighttime electric usage. There are a number of days where that could occur, but throw in a cloudy day, or afternoon showers which happen almost daily here in the summer - no way.
So at least in my house, going totally off grid really won't work. Unless I'm missing something. And the cost of the battery system would be astronomical.