What is Modbus on a solar inverter?

Modbus is a way for your inverter to share its numbers with other devices on your home network. It is often switched off when the inverter is installed. A solar hub like RayHub needs it switched on so it can read what your solar, house, grid and battery are doing right now.

This page explains what to look for and what each of the 13 inverter brands RayHub is built for needs. The brand-by-brand steps are on the connect page.

What switching it on does

It lets another device on your home network ask your inverter for its readings.

  • The setting is usually called Modbus TCP

    Look for Modbus TCP, or a Modbus TCP server, in your inverter's app or its own web page. Where it lives depends on the brand. The table below shows where for each one.

  • RayHub only reads

    Nothing on your solar hub changes how your solar system runs. RayHub asks your inverter for its numbers and shows them. Every reading comes from your inverter's own data, so accuracy follows your inverter.

  • Your inverter and RayHub share one home network

    RayHub joins your home WiFi. Your inverter must be on that same network, by WiFi or by cable. If it is on its own separate network, RayHub can't reach it.

  • RayHub also needs your inverter's IP address

    That is your inverter's number on your network, four numbers with dots, such as 192.168.1.50. The connect page shows where to find it.

What each brand needs

Some brands you can switch on yourself. Some need your solar installer. Some need a small adapter first.

SigenergyVerified in a real home

You can switch it on yourself in the mySigen app. Go to System, then System Settings, then Modbus TCP Server Settings, and switch the server on. No port number is needed.

GoodWeWorkshop tested

If your inverter has a network cable, or a LAN and WiFi kit, give RayHub its IP address. If nothing shows up, the Modbus TCP setting may be off. We don't have confirmed steps for it yet, so check your inverter's manual or ask your installer.

If your inverter only has a small WiFi stick, give RayHub the stick's address with :8899 on the end.

SungrowWorkshop tested

Usually called Modbus TCP. We don't have confirmed menu steps yet, so check your manual or ask your installer. If your inverter has its own network cable socket, use that. The small WiNet-S WiFi stick allows only one connection at a time and it can drop out.

Fronius GEN24Workshop tested

Switch on the Modbus TCP server in the inverter's web page, under Communication, then Modbus. RayHub also needs the SunSpec Model Type set to int + SF.

That setting changes how the inverter lays out its readings, so anything else that reads your inverter would then read the wrong numbers. If something else reads it, ask your installer first. The full steps are on the connect page.

SolarEdgeWorkshop tested

Usually called Modbus TCP, set in SolarEdge's SetApp, which normally needs your installer. It often uses port 1502, so the address may need :1502 on the end. It allows one Modbus connection at a time, so if another system already uses it, RayHub can't connect. Our testing covers systems without a SolarEdge battery.

VictronWorkshop tested

RayHub reads through the GX device, such as a Cerbo GX. In its menu go to Settings, then Services, and switch Modbus TCP on. It is off when the GX device is new.

AlphaESSWorkshop tested

Usually called Modbus TCP. You may find it in the AlphaESS app under Settings, then Communication. If not, ask your installer. It allows one Modbus connection at a time. Some older systems have no network connection for Modbus and need an extra adapter. These notes are for SMILE systems.

Deye / SunsynkWorkshop tested

Single phase and three phase hybrids share their data through a wired RS485 port, so they need a small gateway box to join your home network, such as the Elfin EW11. Ask your installer for one. When the gateway runs in Modbus TCP mode, give RayHub its IP address. When it runs as a plain UDP link, add :8899 on the end.

The small WiFi stick that comes with many of these inverters is for the Solarman cloud app. RayHub can't read through it, so give RayHub the gateway's address, not the stick's.

Fox ESSWorkshop tested

Fox ESS switched off readings through the inverter's network port in newer firmware. Current hybrids (KH, H3 Pro, H3 Smart and EVO) share their data through a wired RS485 port instead, so they need a small RS485 to WiFi adapter set to Modbus TCP mode, such as the Elfin EW11. Ask your installer. Give RayHub the adapter's address, not the address of the Fox ESS WiFi stick.

SolaXWorkshop tested

For X1 and X3 Hybrid Gen2 and Gen3, connect the inverter's own network port to your home network with a cable and give RayHub its IP address. Give RayHub the inverter's address, not the Pocket WiFi dongle's. Gen4 inverters, including the Qcells Q.VOLT, aren't covered yet.

SolisWorkshop tested

For hybrids with a battery, such as the S6-EH1P and S6-EH3P. Whether your logger stick can share readings on your network depends on the stick and its firmware. The dependable route is an RS485 to WiFi adapter set to Modbus TCP mode. Ask your installer for one and give RayHub the adapter's address.

If you read through a Solis logger stick instead, the stick allows one Modbus connection at a time.

SMAWorkshop tested

Your installer switches on the Modbus TCP server in the inverter's own web page. A factory reset switches Modbus off again. RayHub updates SMA numbers every 10 seconds, and grid readings need an SMA Energy Meter.

GrowattWorkshop tested

For MIN XH and MOD XH hybrids. Most Growatt WiFi sticks only talk to the Growatt cloud app. The ShineWiLan-X2 stick is the one RayHub can read through. Otherwise ask your installer for an RS485 to WiFi adapter set to Modbus TCP mode. SPF off-grid inverters aren't covered. Please don't connect RayHub to one.

Verified means RayHub has run in a real home with that brand. Workshop tested means we have built support for it and tested it in our workshop. It has not run in a real home yet, and the steps for those brands haven't been checked in a real home either.

When a small adapter comes into it

Not every inverter puts Modbus on your home network by itself. Deye / Sunsynk and Fox ESS share their data through a wired RS485 port, so they need a small RS485 to WiFi adapter near the inverter. Solis and Growatt depend on the logger stick fitted. An adapter is the dependable route for Solis, and the route for Growatt if your stick isn't a ShineWiLan-X2.

For Deye / Sunsynk and Fox ESS, the WiFi stick that sends your data to the brand's own cloud app is a separate part, so give RayHub the address of the adapter, not the stick's. GoodWe and Growatt are different. A GoodWe WiFi stick, or a Growatt ShineWiLan-X2, can be the address RayHub reads through. The table above says which applies to your brand.

Many solar installers already fit these adapters for monitoring tools. Show them the connect page.

Before you switch it on

  1. Check if something else already reads your inverter

    SolarEdge and AlphaESS allow one Modbus connection at a time, and so does a Solis logger stick. If another system already uses it, RayHub can't connect. On a Fronius GEN24, the setting RayHub needs would change the numbers anything else sees.

  2. Ask your router to keep your inverter's address

    Routers call this a reserved or fixed address. It stops the number changing later. If it changed, RayHub would lose your inverter.

  3. Check it again after a reset

    On SMA, resetting the inverter to its factory settings switches Modbus off again. If your numbers stop after a reset, ask your installer to switch it back on.

Questions

Is Modbus an app or a cloud service?

No. It is a setting on your inverter that lets devices on your home network read its numbers. RayHub has no account, no cloud service and no subscription, and your energy readings stay in your home.

Do I need an electrician?

It depends on the brand. On Sigenergy you can do it yourself in the mySigen app. For SolarEdge, SMA and the brands that need an adapter, ask your solar installer.

What if my inverter brand isn't listed?

RayHub is built for 13 brands. It isn't covered yet for Neovolt and ByteWatt, older Fox ESS such as the H1, SolaX Gen4 including the Qcells Q.VOLT, Solis without a battery, and the Growatt MIN TL-XH2, SPH and SPA. When you register your interest, you can choose Not sure or Something else.

Can I use RayHub yet?

RayHub is pre-production and pre-orders have not opened. Register your interest and we'll email you when they do, with the price and the brands supported at that point.