400 amp service, Span.IO, Tesla Batteries and Solar

[Weeandthewads]

I am not new to Solar and batteries. I have been through two purchases and install over the last 6 years. I am now facing my third and it feels like I have learned nothing. Currently we are building a home. The house house will have a main 400a circuit entering the home and at this point I get confused. There seems to be a significant issue when your main box exceeds 200 amps. How do you configure a 16k array with 54kw of battery servicing 400a of circuits in a single home? It appears that you either split the array system in two independent systems or separate the circuits to ignore and place them in a second box. For the amount of money being spent neither of these answer are acceptable. Does anyone have a config where the entire property is served by the array and batteries? I am not looking to play games with the circuits and breaker boxes. I was interested in the Span.IO system but they don't seem to have a 400 amp solution. IEvery thing seem to revolve around 200amps. That seems to make the config two separate systems. Help! Has anyone conquered this?

[Ampster]

A 200 Amp subpanel or subpanels are not the end of the world. If you are actually thinking you need that many Amps you should be thinking about three phase because for big motors three phase motors are much more efficient.
I believe the Tesla Gateway is only rated for 200 Amps. Tesla itself does not install in new construction so your best bet is to find a Tesla installer or other solar installer to work with your electrician to layout your electrical infrastructure. Have you done a load analysis?

The size of the battery in kWhs has no effect on the calculations since it is the inverter capacity that figures into the calculations. Is the 54 kW of batteries the inverter capacity? That is more than a couple of Tesla Powerwalls. The Tesla Powerwall has a battery capacity of 13.5kWh and the internal Inverter has a continuous output capacity of 5.8kW which is 24 Amps. Eight of those would just barely be 200 Amps.

There also may be fire code restrictions and NEC 2020 has rules about how many kWhrs of batteries can be located where. Those are all planning decisions that are worth getting professional advice. Is this in California? Some states have energy calculations that are required for the building envelope and spending more than the minimum to insulate the building envelope can save quite a bit in energy consumption down the line.

[Mike90250]

First, not many batteries can power a large 400A 240VAC load for very long, don't let the salesman BS you. Batteries are for running the essential loads:
beer cooler, deep freeze, a microwave or induction hot plate, a small air conditioner, house lights, radio or TV Not the gut thumping home theater or charging the car ( except in daylight )

[solarix]

Its bad enough trying to do whole house battery backup with a 200A panel. I've never heard of anyone doing a 400A. For one thing a 400Amp panel is really a dual 200. You could put in two transfer switches - one on each 200A buss. It all gets very expensive when adding batteries. I assume your battery is 54kWh not 54kW - big battery but even so, a 400A load will drain it in less than an hour. You could put all your important loads on one of the 200A busses and just backup that.