I don't believe they are UL certified, but Dumfume sells 3.6kwh (300ah-12v) lifepo4 batteries for $320. 15 of those would get you 54kwh for <$5k. Might be tough to be anywhere near that point for UL certified only, though.
It’s an NEC violation (and also incredibly reckless) to connect electrical equipment that has not been tested by a NTRL. [0]
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.
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...