Stop paying to import — automatically divert your solar surplus to the water heater.
K1 is the standard solar-router kit. On top of the DimmerLink dimmer it adds an rbAmp UI module on your grid feed — voltage and current, so it senses direction (import vs. export). That lets the router keep your grid exchange near zero, avoid paying for imported power under the diverted load, and cap grid draw to a set limit — no battery bank needed.
What's in the box
- DimmerLink phase-cut dimmer — choose 16 A / 24 A / 40 A (≈ 3.7 / 5.5 / 9.2 kW at 230 V) with on-TRIAC temp sensor, heatsink, and active fan
- rbAmp UI measurement module — line voltage + 1 current channel (grid role, voltage-capable signed power), factory-calibrated, with on-board I2C pull-ups (sufficient for a bus run under ~30 cm)
Not included: the CT clamp (no SCT-013 clamps in the kit — add one to match your grid conductor), ESP32 / ESP32-C2 host, cabling, enclosure, and power supply.
Modes unlocked
Adds GRID_LIMIT · ECO · AUTO to K0's OFF/MANUAL/BOOST. See Operating Modes and Overview §1.7.
Fully open source — source code & firmware on GitHub; pre-built binaries for ESP32, C2-HTTP, and C2-MQTT
Key features
- Voltage-capable grid sensing (import vs. export) — factory-calibrated, galvanically isolated rbAmp; no ADC tuning
- AUTO — keeps grid exchange near zero; all solar surplus heats your load
- ECO (anti-import) — trims the load whenever you'd start buying from the grid; export stays untouched
- GRID_LIMIT — caps grid draw by current to stay under a supply/breaker limit
- Benefits without batteries and without needing to export
- Runs on ESP32 / ESP32-C2; MQTT + Home Assistant, REST, OTA (ESP32)
Who it's for
Homeowners optimizing solar self-consumption / anti-import, and sites on a limited grid supply that must cap consumption.
What you'll also need
- A clamp-on CT for the grid conductor (SCT-013 series or compatible — not included)
- ESP32 / ESP32-C2 host (not included), a 3.3 V supply, I2C cabling, and an enclosure
- Solar PV generation (to have surplus to divert), an AC-mains resistive load, and WiFi
Specifications
| Parameter | Value |
|---|---|
| Dimmer | DimmerLink phase-cut (I2C), 16 / 24 / 40 A, active thermal management |
| rbAmp | UI — line voltage + 1 current channel (grid, voltage-capable / signed power) |
| CT (clamp-on) | Not included — SCT-013 series or compatible, matched to your grid feed |
| Measurement | Current + line voltage → signed active power, PF, frequency |
| Calibration | Factory-calibrated; select CT model (no gain/offset tuning) |
| Bus pull-ups | On-board on rbAmp (adequate for I2C run < ~30 cm) |
| Isolation | rbAmp galvanically isolated |
| Operating modes | + GRID_LIMIT, ECO, AUTO (over K0) |
| Host | ESP32 / ESP32-C2 — not included |
| Bus | I2C (rbAmp + DimmerLink on a shared bus) |
| Connectivity | WiFi · REST · MQTT / Home Assistant · OTA (ESP32) |
| Firmware | Open source (ESP32 & ESP32-C2 builds) |