Recommendations for Inverters with Full Modbus Protocol Support and Register Maps

[Watchara]

Hi everyone,

I'm looking for an inverter that supports custom code writing via the Modbus protocol over RS485. It would be great if the inverter comes with a comprehensive and well-documented register map.

Do you have any recommendations for specific brands or models? I'm planning to purchase one for my project. Any advice or insights would be greatly appreciated.

Thanks in advance!

 

[BentleyJ]

Schnieder XW Pro 6848 has hundreds of Modbus Registers and is capable of full remote monitoring and control using a 3rd party PLC.

 

[marionw]

Most SRNE (or SRNE Clones) also have a well documented Modbus Register map/protocol.
I have an SunGoldPower 10kw and can read all registers as well as write those that are writeable.

Just research each inverter you might be interested in. Even email the manufacturer or distributor to see if they can/will provide you with the protocol document. SunGoldPower was very helpful with me in not only providing the protocol document but answering a number of questions about some of the registers.

 

[rogerheflin]

Most of the luxpower/eg4 models seem to document the modbus. A bunch of us are using modbus to get metrics. I don't know that anyone has yet written the code to change something via home assistant -> mqtt -> app-talking-to-modbus -> inverter.

https://www.dth.net/solar/luxpower/modbus/EG4-18KPV-12LV-Modbus-Protocol.pdf

The other luxpower derived models seem to follow some slight variation of the parameters and also should have similar documents available.

 

[Watchara]

Most SRNE (or SRNE Clones) also have a well documented Modbus Register map/protocol.
I have an SunGoldPower 10kw and can read all registers as well as write those that are writeable.

Just research each inverter you might be interested in. Even email the manufacturer or distributor to see if they can/will provide you with the protocol document. SunGoldPower was very helpful with me in not only providing the protocol document but answering a number of questions about some of the registers.

Thank you for sharing this information!

I currently have an SRNE inverter, but I’ve been having trouble connecting to it via RS485 to communicate with the inverter. I’ve tried various methods but haven’t been successful so far.

Do you have any advice or suggestions on how to properly set up the RS485 connection or troubleshoot this issue? Any tips would be greatly appreciated!

Thanks in advance!

 

[kommando]

I have lots of Modbus RTU and TCP devices, when querying them not all modbus programs act in the same way as the spec is so open and so make you think the device is not working. So you need more than one program to have a chance to connect.

This is one I use which can be used on a PC with Java installed.

GitHub - SciFiDryer/ModbusMechanic: Cross platform GUI MODBUS TCP/RTU simulator & gateway. Interprets data types including ascii float and int.

Cross platform GUI MODBUS TCP/RTU simulator & gateway. Interprets data types including ascii float and int. - SciFiDryer/ModbusMechanic

github.com

Also not everyone has the same idea about the A B wires so its worth swapping them over, also if using a network cable make sure it has good copper wires and not copper plated aluminium. Also note the need for 120 ohm resistors at both ends, you can get away without is the cable is short. Also if you have a GND wire its good to connect it both ends so it can be used as a reference 0V for the two signal wires.

01 Coil status will not get a response off most devices, try 03 and 04.

 

[marionw]

Thank you for sharing this information!

I currently have an SRNE inverter, but I’ve been having trouble connecting to it via RS485 to communicate with the inverter. I’ve tried various methods but haven’t been successful so far.

Do you have any advice or suggestions on how to properly set up the RS485 connection or troubleshoot this issue? Any tips would be greatly appreciated!

Thanks in advance!
View attachment 272990

First is the cat5 cable. Your inverter manual hopefully will give you a pinout of the RJ45 jack on the inverter. For many inverters the RJ45 jack that the WIFI adapter plugs into has an RS485 bus on pins 7&8 and pins 1&2 have power for the WIFI adapter, Just make sure you are connected to the "WIFI" RJ45 jack and not the "BMS" jack. Many inverters also have a USB jack that can be used.

I am not familiar with the "Open Modbus" software but you might have to select "03: HOLDING REGISTER" as the SRNE Modbus protocol uses 03 to read and 04 to write registers. Also most of the important stuff starts at register 100 (Battery Power SOC)

You can download the "iPower" software that works for many SRNE inverters:

https://www.srnesolar.com/wp-content/uploads/2021/12/Solar-Station-Monitor-Inverter-PC-V1.6.zip.

This software might help you to confirm your ability to connect to and communicate with your inverter.
The "Configuration" screen will show battery voltages as if you are using a 12vdc battery. Just multiply the values by 4.

 

[Watchara]

Thank you both for your helpful advice. After rearranging the signal wiring and connecting the LAN cable with the RS485 adapter as shown in the picture, I am now able to get a response from the inverter.

However, the inverter is currently returning an "Address Error." Would you happen to have any information regarding the register addresses for the SRNE inverter?

Thank you very much!

 

[kommando]

If the register map is not available then you have to perform a scan using one of the Modbus programs, Modbus mechanic I linked to in my last post can do this.

 

[ricardocello]

For Future Reference
The Victron ecosystem supports extensive well-documented ModbusTCP on a centralized GX device such as the Cerbo GX.
All interconnected devices (Inverters, MPPTs, shunts, BMS, etc, regardless of their electrical interface) are mapped into accessible registers.
It’s a different approach.

 

[poldim]

My solark does this but their stance and lack of support on this makes me not want to recommend them

This integration of great except for all of the changes in upstream pymodbus:

GitHub - pbix/HA-solark-PV: Home Assistant integration for the SolArk PV Inverter

Home Assistant integration for the SolArk PV Inverter - pbix/HA-solark-PV

github.com