A smart home interface for Sofar HYD-xx00-KTL (HYDV2) solar and battery inverters.
Forked from Sofar2mqtt and rewritten as a modular, maintainable firmware targeting the HYD 20 KTL (HYDV2 register map). Runs on an ESP8266 with a TFT touchscreen and RS485 transceiver (e.g. the Tindie module).
- Modbus RTU polling of ~90 HYDV2 registers (system, grid, PV×2, battery×2, energy counters)
- MQTT state publishing as a single JSON payload with configurable interval
- Home Assistant auto-discovery for ~45 sensors + a battery-saver switch
- Battery Saver mode — charges from excess solar, prevents grid discharge
- ILI9341 TFT dashboard with XPT2046 touch toggle for battery saver
- Web dashboard at
http://<device-ip>/with live data, settings, and battery-saver control - WiFiManager captive portal for first-time WiFi + MQTT setup
- ArduinoOTA for over-the-air firmware updates
- TaskManagerIO cooperative task scheduling (no blocking delays in the main loop)
- ArduinoJson v7 for all JSON serialisation
Subscribe to <deviceName>/state for a JSON payload containing:
run_state, inverter_temp, heatsink_temp
grid_freq, inverter_power, grid_power, grid_voltage, load_power
pv1_voltage, pv1_current, pv1_power, pv2_voltage, pv2_current, pv2_power, pv_total
batt_voltage, batt_current, batt_power, batt_temp, batt_soc, batt_soh, batt_cycles
batt2_voltage, batt2_current, batt2_power, batt2_temp, batt2_soc, batt2_soh, batt2_cycles
batt_total_power, batt_avg_soc, batt_avg_soh
today_gen, total_gen, today_use, total_use, today_imp, total_imp, today_exp, total_exp, today_chg, total_chg, today_dis, total_dis
working_mode, battery_save, battery_save_target, modbus_ok, mqtt_ok, wifi_ok, uptime
These topics require the inverter to be in Passive Mode. All commands disable battery saver first, except /set/battery_save itself.
<deviceName>/set/battery_save— payloadon,true, or1enables battery saver. Any other payload disables it.<deviceName>/set/charge— payload is watts. Positive values charge the battery (e.g.3000), negative values discharge it (e.g.-3000).<deviceName>/set/standby— payload is ignored. Sets inverter to standby (0 W output).<deviceName>/set/auto— payload is watts (e.g.5000). Returns the inverter to autonomous mode with a charge/discharge limit of ±N watts. If the value is ≤ 0 or missing, defaults to ±16384 W (effectively unlimited).
When enabled, the firmware reads grid power every 3 seconds and adjusts the battery charge target so that only excess solar is stored. The battery never discharges to the grid — the charge target is clamped to 0–20000 W (BSAVE_MAX_POWER). Even at 0 W, the command is sent as a keep-alive (the inverter times out after ~60 s without a write).
The battery saver has no user-configurable limits — it automatically tracks available solar surplus. The 20 kW ceiling matches the HYD 20 KTL inverter rating and can be changed in Config.h.
This is a PlatformIO project. All dependencies are managed automatically.
pio run # compile
pio run -t upload # flash via USB- Adafruit ILI9341, Adafruit GFX Library
- XPT2046_Touchscreen
- PubSubClient
- WiFiManager
- ArduinoJson v7
- TaskManagerIO
- MCU: ESP8266 (ESP-12F), 160 MHz
- Display: ILI9341 TFT (SPI) + XPT2046 touch
- RS485: Hardware Serial (TX=1, RX=3) to MAX485/MAX3485 transceiver
- Pins: TFT CS=D1, DC=D2, LED=D8, Touch CS=0, Touch IRQ=2
Connect RS485 A/B wires to the inverter's 485s port. Power the module from 5V USB.
On first boot (or after factory reset), the device starts a SofarBatterySaver WiFi access point. Connect to it and configure:
- WiFi credentials
- Device name (used as MQTT topic prefix and mDNS hostname)
- MQTT host, port, username, password
Settings can also be changed via the web UI at http://<device-ip>/.
Originally based on Sofar2mqtt by Colin McGerty. Version 2.0 rewrite by Adam Hill. Version 3.x by Igor Ybema (TFT, multi-inverter support). CRC routines by Angelo Compagnucci and JP Mzometa. HYDV2 rewrite and modularisation by Valentinas Bartusevičius.
