SRNE Solar Controller

Monitor and control SRNE ASP/ASF-series hybrid inverters via MODBUS over Solarman V5 wifi dongles.

Integrates with Home Assistant through MQTT auto-discovery, providing ~65 sensor entities and 7 writable controls. Also includes a live web dashboard and CLI for direct register access. Supports multi-inverter parallel systems with aggregated data and synchronized settings writes.

Home Assistant Add-on

Prerequisites

• A Solarman V5 wifi dongle (LSW-3, LSE-3, etc.) connected to your inverter
• The Mosquitto broker add-on (or an external MQTT broker)

Installation

Add this repository URL to your Home Assistant add-on store:

https://github.com/daniel-sullivan/srne-solar-controller

Install the add-on, then configure your inverter connection(s) in the add-on settings:

Option	Description
inverters[].host	IP address of the Solarman dongle
inverters[].port	TCP port (default 8899)
inverters[].slave_id	MODBUS slave ID (default 1)
inverters[].serial	Dongle serial number (0 = auto-detect)
poll_interval	Seconds between polling cycles (default 10)

MQTT is auto-configured from the Mosquitto add-on. Optional overrides (mqtt_broker, mqtt_topic_prefix, mqtt_username, mqtt_password) are available for external brokers.

Start the add-on. Sensor and control entities appear automatically under the MQTT integration.

Auto-Discovered Entities

Sensors (~65 entities): Battery SOC, voltage, current, power, temperature. PV1/PV2 voltage, current, power. Load power, apparent power, power factor. Grid voltage, current, frequency per phase (L1/L2). Inverter state, bus voltage, heatsink temperatures. Daily and lifetime energy statistics.

Controls (7 entities):

Entity	Type	Description
Charge from Mains	Switch	Toggle grid charging. Remembers previous charger priority and restores it on OFF.
Charger Priority	Select	CSO (PV Preferred) / CUB (Mains Preferred) / SNU (Hybrid) / OSO (PV Only)
Output Priority	Select	SOL (Solar First) / UTI (Utility First) / SBU (Solar, Battery, Utility)
Max Charge SOC	Number	Stop charging at this SOC (0-100%)
Discharge Cutoff SOC	Number	Hard minimum battery SOC (0-100%)
SOC Switch to Mains	Number	Switch to grid power below this SOC (0-100%)
SOC Switch to Battery	Number	Switch back to battery above this SOC (0-100%)

Web Dashboard

The add-on includes a web dashboard accessible via the HA sidebar (ingress). It provides real-time monitoring with live-updating panels and a full settings editor for all inverter parameters.

Supported Hardware

SRNE ASP and ASF series hybrid inverters connected via Solarman V5 wifi dongles. Communication is over TCP port 8899 using the Solarman V5 protocol wrapping MODBUS RTU.

Tested with ASP48100U200-H units in split-phase 120/240V parallel configuration.

Standalone Usage

The controller can also run outside Home Assistant as a standalone service or CLI tool.

Prerequisites

• mise (manages the Go toolchain)

mise install

Service Mode

Create a srne.toml config file:

[server]
poll_interval = "10s"
web_port = 8080
settings_refresh = "5m"

[[inverter]]
host = "10.100.3.92"
port = 8899
slave_id = 1

[[inverter]]
host = "10.100.5.55"
port = 8899
slave_id = 2

[mqtt]
broker = "tcp://localhost:1883"
client_id = "srne"
topic_prefix = "homeassistant"

mise run serve

The web dashboard is available at http://localhost:8080. The MQTT section is optional when running standalone.

CLI

# Display inverter product info
mise exec -- go run . info --host 10.100.3.92

# Dump all register groups
mise exec -- go run . dump --host 10.100.3.92 all

# Dump a specific group: battery, inverter, settings, stats, faults, timed
mise exec -- go run . dump --host 10.100.3.92 battery

# Read specific registers
mise exec -- go run . read --host 10.100.3.92 0x0100 10

# Write a register
mise exec -- go run . write --host 10.100.3.92 0xE001 0x0036

# Probe for undocumented registers in a range
mise exec -- go run . probe --host 10.100.3.92 0xE100 0xE150

# Passively scan dongle traffic
mise exec -- go run . scan --host 10.100.3.92

Global flags: --host (required), --port (default 8899), --serial (auto-detected if omitted), --slave (default 1), --debug.

REST API

Endpoint	Method	Description
/api/snapshot	GET	Current system snapshot (JSON)
/api/snapshot/stream	GET	SSE stream of snapshots
/api/settings	GET	Current inverter settings
/api/settings/write	POST	Write settings ({"changes": [{"field": "...", "value": "..."}]})
/api/faults	GET	Fault history records
/api/entities	GET	All entity metadata (sensors + controls) with current state
/api/controls/{key}	POST	Write a control value ({"value": "..."})

Architecture

CLI/API -> modbus.Session (cache + retry) -> modbus.Client -> Solarman V5 (TCP:8899) -> MODBUS RTU -> Inverter

Package	Role
modbus/	MODBUS RTU framing, CRC16, Client interface, Session (register cache + exponential backoff retry)
interfaces/solarman/	Solarman V5 TCP transport with serial auto-detection, interleaved response filtering, and automatic reconnection
interfaces/mock/	Mock inverter and live simulator for testing
register/	Register definitions, context-aware scaling (ScaleFunc), fault code lookup
inverter/	Multi-inverter system management, typed snapshots, aggregation, settings encoding
serve/	Polling hub, MQTT publisher with HA control entities, web dashboard (HTMX/SSE), REST API
cmd/	Cobra CLI: read, write, dump, info, scan, probe, serve

Building

mise exec -- go build ./...
mise exec -- go test ./...

References

• SRNE ASP 8-10kW User Manual
• SRNE MODBUS Protocol PDFs
• ha-solarman -- Solarman V5 protocol implementation, SRNE inverter profile
• V2.08 Protocol + ESPHome YAML -- Latest known protocol PDF

License

See LICENSE for details.