I've been eyeing the home battery space and every year there are new options(mostly from China) to get 10-15kwh stored. Powerwalls aren't keeping up in per kwh value. At some point it's gotta be cheaper to just buy a tesla and strip the battery(assuming you have the skill to remove and repurpose it).

Model 3 or Y with 70-80KWH capacity battery ~~ $40-50,000

Powerwall price: ~$15,000 for 13.5 kwh storage.

You're paying around double for a fancy case and the UI.