You've got to be really careful if you are using battery storage in your house. Lots of regulations around them. I had a plan but while it would have been entirely safe (located in a concrete room outside of the building envelope above grade but in the basement), it isn't allowed unless you apply for a site specific variation. Also, no homebrew allowed, it must be a manufactured assembly with an ANSI/CAN/UL 9540 rating.There's a thriving hobbyist demand for end of life EV packs for these sorts of systems. Even when they're done being viable for an EV they still work awesome for storage systems.
The Volt packs are particularly well loved in the hobbyist community.