if you could tell me where I could get UL certified 43kWh battery for $5,400 I'd be very interested.
No inspector will sign off on a non-listed piece of electrical equipment, especially for a homeowner.
I repeat, do not connect electrical equipment to your home’s electrical distribution network unless it is tested by one of the labs listed in the link below, especially if it is hardwired.
[0] https://www.osha.gov/nationally-recognized-testing-laborator...
https://www.expertpower.us/products/10800w-50kwh?_pos=2&_sid...
That's 50KWH of battery, plus the 10.8KW of solar, inverters, etc., all for $17K. That system is microgrid (not grid following) capable; so, you can run it during a blackout. The switchover is pretty good, too, so you don't need a second backup system.
Example kit:
https://signaturesolar.com/complete-off-grid-solar-kit-eg4-6...
Add in a 15 kWh module and it's roughly the same price with better customer service, reliability, less parts, etc.
However, I would just get an EG 18k PV, 45 kWh of EG5 batteries and 11.4 kW of solar panels from signature solar and that would cost you $18.5k
https://www.apexiummall.com/index.php?route=product/product&...
https://yixiangpower.com/products/yixiang-vertical-15kw-diy-...
Both would cost roughly $4800~$5500 for that total size.
If you want good customer service, dependable, UL listed, and correctly priced, then this is the king: https://signaturesolar.com/eg4-wallmount-indoor-battery-48v-...
UL listed ~45 kWh will cost you $10k, not $5.4k.