This device is quite dense and priced accordingly. Other dumb UPSs or "solar batteries" with this level of battery capacity are all around $1000.
Great work on the local API first approach. I can't remember the last SmartAppTM device that was local API first and not wholely dependent on some fly-by-night SaaS that requires you to sign-up. Hope we see more of this in the industry. Span is infamous for removing local API control of their panels.