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A living reference for adapting the ESP32 local inverter control build to other brands: what transfers as-is, what changes per brand, where to find register maps, and the quirks that bite.

My heat pump was invisible to the inverter and my EV charger was confusing it. Moving one CT clamp fixed the first problem with zero software; a small Home Assistant automation driving the part 1 ESP32 fixed the second.

Hardcoded entity IDs go stale the moment someone reshapes your shared test environment. I banned them: every spec names the shape of data it needs, and a ScenarioResolver finds a real entity at fixture time.

Wire a cheap ESP32 and RS485 transceiver to a Growatt SPH5000 inverter, flash ESPHome, and get a local Modbus web UI for monitoring and control — no cloud, no app.

Security said no to TOTP, no to service accounts, no to disabling MFA. So I built a solution that uses OAuth2 refresh tokens to maintain Playwright browser sessions in CI/CD—without ever triggering push notification MFA after the initial setup. Here's the COSMIC Auth Pattern.