Pull data from Solis S2-WL-ST data logger using TCP without additional hardware. Send the data to a MQTT server with Home Assistant auto discovery.
Warning
- I don't know much about MODBUS
- I don't know anything about inverters
- I don't know much about data loggers
- I don't know much Python
You have been warned!
This journey started before I got my Solar panels installed. I knew I would get a Solis S5-GR3P15K inverter and the S2-WT-ST data logger. I use Home Assistant and I try to have all my devices working locally without relying on cloud solutions. So I started researching existing Home assistant integrations and other solutions to be prepared. I found many alternatives but many of them required extra hardware. But it seemed that the S2-WT-ST is one of few (only?) Solis data loggers that could be used to get data over TCP. Seeing that a few people had success after getting the firmware updated to 10010117 or higher made me confident that I would have this up and running quickly.
When the Solar panels, inverter and data logger was installed I realised that it wasn't as easy as I had hoped. I tried the different integrations and solutions but nothing worked. I got the firmware updated to 10010125 and the support person informed me that what I was trying to do would probably not work. I tried again but still nothing worked. I started looking at simpler ways of trying to talk to the data logger over TCP to be able to debug and run tests and found a few example script written in Python. I was able to connect to the stick but none the registers used in different integrations was working.
Then I found solis2mqtt, it used a completely different set of registers and now I was able to make progress. I could match the data I got from the logger (still using my own test scripts) to what I could see in the Solis cloud app!
I started to set up solis2mqtt but quickly realised that it was not using TCP. Now you might ask, why not contribute to that project and add TCP support. The short answer is that the MODBUS library used does not support TCP so it would require a larger rewrite. I also see this project as a way of learning about both MODBUS and Python.
Finally I found a PDF that seems to have the correct registers listed. It's available in the reference folder. Using this PDF it will be possible to add even more sensors than those that I found referenced in the solis2mqtt project.
So many hours later, here we are. Debug code turned in to a hack turning into a hobby project.
So will this project work for you? I have no idea. I'm just hacking away on something to make it work for me and at the same time publish it here and by doing this I might be able to help someone else in the same situation.
I've used the solis2mqtt repo as an inspiration and I've borrowed some code since that project does a lot of similar things to what I want to do.
- Only tested with a Solis S2-WL-ST data logger with firmware 10010125 and a Solis S5-GR3P15K inverter with firmware 83003A
- A static IP on the data logger
- Docker
- MQTT server
Because it works! If I for some reason would stop using this myself then I will archive this repo. So as long as the repo is in a "non archived" state then I'm using this myself and it works as expected even if there hasn't been any new versions in a while. I will keep dependencies up to date so a new minor/patch version will be available every now and then.
Most other integrations that I found all stated that Solis Cloud would not work when polling the data logger over MODBUS. In my brief and short testing Solid Cloud still works, but not perfectly. My guess is that most other integrations keeps the connection with the data logger alive while this project closes the connection when its done and then reconnects when it's time for the next update. By "not perfectly" I mean that I can see that Solis Cloud is not always updated every 5 minutes. Sometimes it takes 15-20 minutes between updates but I've always seen that the data logger sooner or later are able to send data to Solis Cloud. And if I stop the script/Docker container I always seen an update in Solid cloud within 10 minutes without having to restart the data logger.
I have not focused on that since I don't have a need for it. If its possible to do so via MODBUS then it should be possible to add that functionality.
I have no idea. I will probably never change to another data logger or upgrade the firmware unless I absolutely have to. If you are able to get this working on another data logger, inverter or firmware version, please let me know and I will add the information to the repo!
I send an email to a support address for my country that I found here: https://www.solisinverters.com/se/contactus.html. I asked them to update my inverter and logger. I included the models and serial number of the inverter and logger. It took less than 24 hours if I remember correctly.
Maybe, I have no plans for it at the moment. My main goal is to get the data into Home Assistant and I decided to use MQTT to simplify the project a little bit.
Prepare a config file. Use config.example.yaml and modify it to your needs and save it as config.yaml. Most values should be self-explanatory. register_chunks is set to 20 by default but during my testing I've been able to query my datalogger for more than 80 registers at the same time.
It's currently only possible to use environment variables to set MQTT user and password. Use MQTT_USER and MQTT_PASSWORD.
docker run -v "$(pwd)"/config.yaml:/usr/app/src/config.yaml:ro ghcr.io/ahinko/tcpsolis2mqtt:latest
---
version: "3.8"
services:
tcpsolis2mqtt:
container_name: tcpsolis2mqtt
image: ghcr.io/ahinko/tcpsolis2mqtt:latest
restart: always
volumes:
- ./config.yaml:/usr/app/src/config.yaml:ro