A local read of a solar inverter that speaks SunSpec over Modbus TCP (or a closely related official integration), with the useful cumulative kWh figures added to the Home Assistant Energy dashboard. This follows the Modbus overview thread and the Eastron SDM230 meter project, but the device here is the inverter itself.
Complexity
Moderate, if the inverter already has a network port and the installer can confirm Modbus is allowed. Changing inverter wiring, export limits or meter CTs is professional work.
1. Preconditions
- The solar (and battery, if you have one) is already installed by an accredited installer. Do not open the inverter or add unofficial metering.
- You know the exact inverter family and firmware. Official Home Assistant integrations that read SunSpec or vendor Modbus locally include Fronius, GoodWe, SolarEdge Modbus and KACO Modbus. If your brand is not in that list, stop and read the manufacturer's Modbus manual before adding generic registers.
- Give the inverter a DHCP reservation so its IP does not move.
- Home Assistant can reach the inverter on the same trusted network. Home Assistant's Modbus documentation warns that Modbus TCP is unauthenticated and unencrypted. Do not expose port 502 (or the vendor's alternate port) to the internet.
Many inverters ship with Modbus TCP off. Official examples:
- Fronius Gen24, Tauro and Verto: in the inverter web interface, go to Communication, then Modbus, and turn on the Modbus TCP server. The official integration also uses the local Solar API. Modbus is optional for monitoring; it adds extra entities (including per-string data) when the inverter answers. Writing AC power or battery limits is a separate "inverter control via Modbus" setting. Leave writes off unless you and the installer understand export and grid rules.
- GoodWe: official docs say to enable the Modbus TCP option on the communication dongle if you cannot talk to a listed family. They also note that an old ARM firmware (not just the inverter firmware) can block the connection, and that very frequent polling has, in rare cases, interfered with the SEMS cloud portal.
- KACO: official docs describe SunSpec over Modbus TCP, usually port 502 and unit ID 1 for a direct network connection, and only one Modbus client at a time.
- SolarEdge: official docs: use the built-in Modbus TCP interface; no cloud account is required for this path. Firmware may be needed before the setting appears.
3. Add the integration
In Home Assistant: Settings, Devices & services, Add Integration, then pick the official integration for your brand. Enter the host, and the port if asked (502 is common; do not assume it). For a generic documented map only, use the Modbus integration and the manufacturer's register list — do not copy someone else's map for a different model.
4. Choose sensors for the Energy dashboard
You need cumulative kWh, not instantaneous watts.
- Solar production (total PV generation).
- Grid import and grid export, if the inverter or a paired meter provides them.
- Battery charge and discharge energy, if you have a battery and the inverter exposes those registers.
Then: Settings, Dashboards, Energy, and assign those sensors to Solar panels, Grid and Battery. If a power sensor is inverted (positive when exporting, for example), the Energy dashboard has an invert option — read the meaning on your inverter before ticking it.
5. Check a full day before trusting it
- Production should rise on a sunny day and hold overnight.
- Import plus solar (minus export, minus battery changes) should be in the same neighbourhood as household use. A large mismatch is often a CT or meter issue for the installer, not a dashboard theme.
- Do not enable inverter write/control entities for a first install.
If the inverter is already on site, this project is labour and configuration, not a shopping list. A new communications dongle, meter or network run should be quoted in AUD by the installer. There is no single public list price that covers every Australian site.
Official reading
Integrating your solar panels
Fronius · GoodWe · SolarEdge Modbus · KACO Modbus · Modbus
Researched from official documentation on 15 November 2026 (Australia/Sydney). This is a planning and how-to guide, not a claim that the exact hardware combination was assembled and tested on a live site. Please correct anything that has moved on.