Powerwall Charge on Solar (ESP32)

ESP32 firmware that connects directly to a Tesla Powerwall 3 gateway over its local Wi‑Fi and broadcasts key stats via BTHome BLE for easy Home Assistant discovery. Built for LilyGO TTGO T‑Display (ESP32), but easily portable to other ESP32 boards.

The Tesla TEDAPI runs on a local gateway and isn't documented. It uses GraphQL / signed protobufs over HTTP.

Wouldn't have been possible without all of the R&D done over at https://github.com/jasonacox/pypowerwall

Hardware

• Target board: LilyGO TTGO T‑Display (ESP32)
• Display: Onboard ST7789 240x135 TFT (rendered battery and power stats)
• BLE: NimBLE (BTHome v2, unencrypted)

Setup

1. Install tooling

   • VS Code + PlatformIO extension

2. Configure gateway Wi‑Fi credentials

   • Rename src/config.h.template to src/config.h
   • Edit the file and set your Powerwall 3 gateway Wi‑Fi SSID and password:
     • POWERWALL_WIFI_SSID → typically looks like TeslaPW_XXXXXX
     • POWERWALL_WIFI_PASSWORD → printed on the gateway/inside the door
   • Note: src/config.h is already ignored by git.

3. Build and upload

   • Board: env:lilygo-t-display in platformio.ini
   • Click “Upload” in PlatformIO, or run PlatformIO: Upload
   • Open Serial Monitor at 115200 to view logs

What it does

• Connects to the Powerwall gateway Wi‑Fi and queries TEDAPI locally (no cloud).
• Renders a simple battery/power view on the TFT display.
• Advertises a BTHome v2 BLE payload named PW BTHome for passive discovery.

BTHome exposure

• Protocol: BTHome v2, unencrypted, service UUID 0xFCD2
• Advertised entities (Home Assistant will discover these):
  • Battery percent (0–100)
  • Solar power (W)
  • Load power (W)
  • Site power (W) — grid import (+) / export (−) as reported
  • Battery power (W)
• The BLE advertisement contains battery percent followed by four power values in a fixed order: solar, load, site, battery. The payload is broadcast about once per second.

Networking notes

• The ESP32 must be in range of the Powerwall gateway’s Wi‑Fi. It connects only to that SSID and does not require internet.

Porting to other ESP32 boards

• Update platformio.ini pins/display settings as needed, or stub out display.* if running headless.
• BLE and Powerwall logic are board‑agnostic; the main changes are GPIO/display config.

Troubleshooting

• Not connecting: double‑check SSID/password in src/config.h, and ensure you’re near the gateway.
• No BLE in HA: enable the BTHome integration and ensure your HA host supports passive BLE; bring the ESP32 closer.

License

MIT — see LICENSE for details.