ACRouter — Open-Source Solar Router Controller

Intelligent AC Power Router for Solar Energy Management

Overview • How It Works • Features • Hardware • Modes • Quick Start

The dashboard: live grid/solar/load power, the divert level, and the mode selector — here exporting 1200 W into the load in AUTO.

What is ACRouter?

ACRouter is an open-source controller that automatically redirects excess solar energy to resistive loads (like water heaters) via smooth phase-angle dimming — instead of exporting it to the grid. It maximizes self-consumption of your solar power and reduces electricity costs.

Why ACRouter?

Typical daily behavior of a grid-connected PV system with a water-heater load:

Figures are typical estimates and vary with your installation (PV size, load, tariffs, and usage).

How It Works

A v2.0 system is an ESP32-family host plus smart I2C modules:

rbAmp (I2C)  ──▶  sensor_hub  ──▶  RouterController  ──▶  DimmerLink (I2C)  ──▶  load
  measures grid    merges the       decides how much     phase-cut output       (heater)
  (+ solar/load)   sources          to divert (grid→0)    (dimmer id 4)

The rbAmp module measures grid power (and optionally solar/load), the RouterController runs a ~5 Hz balancing loop, and the DimmerLink module drives the load — raising or lowering it so the grid exchange trends to zero. All the surplus is consumed locally instead of exported.

Features

• Smart measurement (rbAmp). Clamp-on CT current + line voltage over I2C; factory-calibrated, no ADC tuning. Grid / solar / load channels.
• Smart dimming (DimmerLink). Phase-angle 0–100% on a dedicated controller; zero-cross handled in the module.
• Seven operating modes for grid-tied, export-protection, off-grid, and manual scenarios.
• External web app — capability-aware UI (the device redirects to it).
• REST API, MQTT + Home Assistant auto-discovery, OTA (ESP32 tier).
• Two targets — ESP32 (full) and low-cost ESP32-C2, with capability-aware feature gating.
• Configurable & persistent — settings in NVS; configure via web app, REST, MQTT, or serial.
• Open source.

Hardware

ACRouter v2.0 uses a modular architecture: an ESP32 or ESP32-C2 host plus rbAmp (measurement) and DimmerLink (dimmer) modules sharing one I2C bus.

Minimum build: one host + one rbAmp (with a grid channel) + one DimmerLink. Wiring, addresses, CT models, and pull-ups are covered in the Hardware Guide.

ACRouter is designed to work with modules from rbdimmer.com and open-source DIY hardware.

Operating Modes

See Router Modes for details.

Source Code & Firmware

ACRouter is fully open-source. The firmware, documentation, and build configuration are available on GitHub:

Pre-built Firmware (v2.0.0)

Download the zip for your target, flash with esptool — see Compilation & Flashing for details.

Each zip contains a 4-file set (bootloader, partition table, OTA data, application) plus flash offset instructions.

Quick Start

1. Flash the firmware for your target/profile (ESP32, C2-HTTP, or C2-MQTT) — see Compilation.
2. Wire the rbAmp and DimmerLink modules to the host's I2C bus (with pull-ups) — see the Hardware Guide. (If you change the default I2C pins, that setting is applied by a reboot before the modules can be discovered.)
3. Power on and connect WiFi — the device starts an access point ACRouter_XXXX (e.g. ACRouter_A1B2); join it, open http://192.168.4.1, give it your home WiFi, then open the external web app (or use serial — no WiFi needed).
4. Commission (in the app or over REST): discover modules (rescan) → assign roles (rbAmp grid channel + CT model; DimmerLink role=dimmer → auto-binds to a dimmer output) → verify the grid sign under a known load.
5. Select AUTO and start saving energy. (Assigning role=dimmer drives the output live; a one-time reboot may be needed for the dimmer's status/telemetry to appear.)

The full walkthrough is in the Commissioning guide.

Documentation

Safety

⚠️ This project involves mains voltage (110 V / 230 V AC).

• Installation by a qualified electrician; de-energize before wiring.
• Proper isolation, fusing, and RCD/GFCI protection; keep low-voltage I2C wiring away from mains.
• Resistive loads only (heating elements) — not motors, transformers, LED drivers, or electronics.

What ACRouter Is Not

• Not a battery inverter · not a smart plug/relay controller · not a certified grid-protection device · not for inductive or electronic loads.

Contributing

Contributions welcome — report bugs, suggest features, improve docs, or submit code via pull request on GitHub.

License

ACRouter is open-source software. See LICENSE for details.

Acknowledgments

• rbAmp / DimmerLink — smart sensing & dimmer modules (rbdimmer.com)
• ESP-IDF — Espressif IoT Development Framework
• ArduinoJson — JSON library for embedded systems
• Community — contributors and testers

Made with ⚡ for the solar energy community

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