A MQTT bridge for Solis solar inverters.

Foreword

I want to start by extending my deepest gratitute to incub who owns the solis2mqtt repository which served as a base for this one (from now on I call his repo the original).

I made several changes:

1. The python script will run single pass, single task. Rationale behind this is that all initializations, cleanup, et cetera is taken care of by the Operation System and is done at every run of the script.
2. In situations that the inverter is unreachable, the sun altitude is used to determine whether this is normal or not. Normal: long wait time, not normal: try again soon.
3. An additional run.sh is added to do the repeating. Sleep duractions are based on the errorlevel of the script.
4. Additional sensors are added to the solis_modbus.yaml file, like the v_dc1, i_dc1, v_ac, i_ac and grid frequency.
5. The On/Off switch and Power limitation are removed because of these changes. They require a continuous listener and that does not fit this design principle. If you need this, use the original.
6. This is work in progress. I'm not sure the setup.sh works like it should as I have not taken time to do the install on an empty Raspberry Pi. So please test it and let me know the results.

All text marked with an ^* is the original text from incub.

Ad 1

When using the original I observed that the connection to the inverter was lost quite fast, like after 10-20 runs. The original then just waits for a longer period of time to try again. There is no reinitialization of the serial port. This observation let me to do this work. Of course I could have put some serial reinitialization into the original but I leave that to another volunteer. And yes, I know I had to sacrfice the On/Off switch and the ability to change the Power limitation.

Introduction^*

Solis solar inverters are equipped with an RS485 interface, through which telemetry values can be read and also control commands can be sent. The manufacturer offers LAN and WLAN sticks in combination with a software solution to access the interface. Unfortunately, this is always coupled with a connection to the manufacturer's cloud and integration into a home automation system is only possible in a detoured manner. This software acts as a bridge between the RS485 interface and a MQTT broker to allow easy integration into a home automation (with special support for Home Assistant), and furthermore without cloud constraints.

Hardware

• The inverter uses a proprietary(?) RS485 plug, with the following pin-out (at least on my wifi stick, it is different than described in the original):

  /-----\
  | 1 4 |
  | 2 3 |
  \--^--/

1. +5V
2. GND
3. DATA+ (A)
4. DATA- (B)

• Any RS485 adapter should do I think. FYI: I use the USB 2.0 RS485 interface FTDI.
• I highly recommend using a proper connector, which can be found on ebay (search for "RS485 Solis" or "Exceedconn EC04681-2014-BF") and solder the wires to it.
• I run the software on a Raspberry Pi 3 Model B Rev 1.2B, but any Linux box should do I guess.

Installation

• Download and install to /opt/solis2mqtt

sudo git clone https://github.com/hvoerman/solis2mqtt.git /opt/solis2mqtt

• Execute setup.sh. This will basically install dependencies, add a system user for the daemon to run in and setup systemd.

sudo bash /opt/solis2mqtt/setup.sh

• To see whether or not the converter is connected, use:

lsusb

My output is

Bus 001 Device 004: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC
Bus 001 Device 003: ID 0424:ec00 Microchip Technology, Inc. (formerly SMSC) SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Microchip Technology, Inc. (formerly SMSC) SMC9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

The Future Technology Devices International, Ltd FT232 Serial (UART) IC is the one we're looking for. I use /dev/ttyUSB0 in my config.yaml

• Edit config.yaml. See section Basic Configuration.

e.g. sudo vi /opt/solis2mqtt/config.yaml

• A reboot is necessary for user rights (access to /dev/ttyUSB*) to become effective.

sudo reboot

Usage

Solis2MQTT is intended to run as a system service. A log file is written to /opt/solis2mqtt/solis2mqtt.log. To control the service, the usual systemd commands are used:

• Start: sudo systemctl start solis2mqtt
• Stop: sudo systemctl stop solis2mqtt
• Restart: sudo systemctl restart solis2mqtt
• Disable start on boot: sudo systemctl disable solis2mqtt
• Enable start on boot: sudo systemctl enable solis2mqtt

To check if the service is running you can do a ps -efH | grep solis2mqtt. The output should look something like this:

pi       14226 10644  0 12:11 pts/2    00:00:00           grep --color=auto solis2mqtt
solis2m+ 12473     1  0 11:43 ?        00:00:00   /bin/bash /opt/solis2mqtt/run.sh

If Solis2MQTT doesn't start up to a point where the log file is written you can check /var/log/syslog for clues.

For development/debugging Solis2MQTT can also be started directly. Make sure to change to the working directory before doing so.

cd /opt/solis2mqtt
python ./solis2mqtt_v2.py -s

The following command line arguments are implemented:

• -v or --verbose Verbose mode. Will output debug logging messages.
• -s or --service Run as service. Meaning also send logging messages to stdout to enable log viewing with:

journalctl -u solis2mqtt.service -f --output=short-iso-precise

• --help See the usage.

Basic Configuration

Configuration is read from config.yaml, that has to contain at least these entries:

device: /dev/ttyUSB0
latitude: <latitude>
longitude: <longitude>
mqtt:
  url: hassio.local
  user: whoami
  passwd: secret

This is a complete config example:

device: /dev/ttyUSB0
slave_address: 1
latitude: <latitude>
longitude: <longitude>
inverter:
    name: solis2mqtt
    manufacturer: Ginlong Technologies
    model: solis2mqtt
mqtt:
    url: hassio.local
    port: 1883
    use_ssl: false
    validate_cert: false
    user: whoami
    passwd: secret

• device: [Required] The path to your RS485 adapter
• slave_address: [Optional] The modbus slave address, default is 1
• latitude: latitude of the solar plant
• longitude: longitude of the solar plant
• inverter:
  • name: [Optional] Used as a base path in MQTT, default is solis2mqtt
  • manufacturer: [Optional] Used for device info in Home Assistant, default is solis2mqtt
  • model: [Optional] Used for device info in Home Assistant, default is solis2mqtt
• mqtt:
  • url: [Required] URL to your MQTT broker
  • port: [Optional] Port of your MQTT broker, default is 1883
  • use_ssl: [Optional] Use SSL for MQTT traffic encryption, default is false
  • validate_cert [Optional] Validate certificate for SSL encryption, default is false
  • user: [Required] User for MQTT broker login
  • passwd: [Required] Password for MQTT broker login

latitude / longitude

You can figure out your latitude and longitude from the URL from the “Link to this page” link on Google maps. Find your location on the map, click on the “Link to this page” link, and then look at the URL in the address bar of your browser. In between ampersands, you should see something like ll=89.123456,-78.912345. The first number is your latitude; the second is your longitude.

Inverter configuration^*

The file solis_modbus.yaml contains a list of entries, that describe the values to read from (and write to) the inverter.
You can add your own entries if you want to read other metrics from the inverter. Especially if it comes to writing to the inverter - use at your own risk :-)
This is an example of an entry:

- name: inverter_temp
  description: Inverter temperature
  unit: "°C"
  active: true
  modbus:
    register: 3041
    read_type: register
    function_code: 4
    number_of_decimals: 1
    signed: false
  homeassistant:
    device: sensor
    state_class: measurement
    device_class: temperature

The following options are available:

• name: [Required] Has to be unique. Used in MQTT path and together with the inverter name (from config.yaml) as part of Home Assistant unique_id
• description: [Required] Used for generating log messages and as display name in Home Assistant
• unit: [Optional] Added to log messages and used for Home Assistant
• active [Required] Set to false if the entry should be ignored
• modbus: [Required]
  • register: [Required] The modbus register address to read/write
  • read_type: [Required] The modbus data type. Currently register and long are supported. Additionally composed_datetime can also be used here (see below)
  • function_code: [Required] The modbus function code to read the register
  • write_function_code: [Optional] The function code to write to the register
  • number_of_decimals: [Optional] Can only be used in combination with ready_type: register. Used for automatic content conversion, e.g. 101 with number_of_decimals: 1 is read as 10.1
  • signed: [Required] Whether the data should be interpreted as signed or unsigned
• homeassistant: [Optional]
  • device: [Required] Used for Home Assistant MQTT discovery. Can either be sensor, number or switch
  • state_class: [Optional] State class for Home Assistant sensors
  • device_class: [Optional] Device class for Home Assistant sensors
  • payload_on: [Optional] In combination with device: switch required. Specifies the payload that indicates the switch is in 'on' position
  • payload_off: [Optional] In combination with device: switch required. Specifies the payload that indicates the 'off' position
  • min: [Optional] In combination with device: number required. Specifies minimum value.
  • max: [Optional] In combination with device: number required. Specifies maximum value.
  • step: [Optional] In combination with device: number required. Specifies step value. Smallest value 0.001.

Special case for datetime

As the datetime information is stored in several registers, there is a special read_type to read this as one ISO datetime string.

- name: system_datetime
  description: System DateTime
  unit:
  active: true
  modbus:
    register: [3072, 3073, 3074, 3075, 3076, 3077] # [year, month, day, hour, minute, seconds]
    read_type: composed_datetime
    function_code: 4
  homeassistant:
    device: sensor
    state_class:
    device_class: timestamp

Screenshots

These are taken rather soon after I got stuff to work, so they are not fully representative. I will replace these screenshots with more representative ones in the near future.

Simple dashboard with APEX chart

APEX chart code is

type: custom:apexcharts-card
graph_span: 48h
span:
  start: day
  offset: '-1day'
show:
  loading: true
  last_updated: true
header:
  show: true
  title: Solar vermogen gisteren en vandaag
  show_states: true
  colorize_states: true
series:
  - entity: sensor.active_power
    stroke_width: 1
    type: area
    curve: smooth
    extend_to: false
    name: huidige productie
    unit: ' W'

• Solar vermogen gisteren en vandaag means: Solar power yesterday and today
• huidige productie means current production

MQTT Broker Integration Overview

Energy Dashboard

Just add the Energy generated today (sensor.energy_generated_today) sensor to the Solar Panels stuff and add (if you like) the forecast to it.