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666djb / solarpi

Solar inverter to MQTT bridge for inverter values
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SolarPi v1.1.0

Description

A bridge between a solar PV inverter and MQTT, written in Typescript and executed using node.js.

SolarPi reads the following values from the inverter:

SolarPi reads and writes the following Time of Use (TOU) values:

SolarPi creates and updates the following Device (SOLARPI Bridge), Control Entities and Sensor Entities automatically in Home Assistant:

![Control Entitites 1](<SolarPi Controls 1.png>) ![Control Entitites 2](<SolarPi Controls 2.png>) ![Control Entitites 3](<SolarPi Controls 3.png>) ![Control Entities 4](<SolarPi Controls 4.png>)

From these, Lovelace Dashboards such as the following can be created.

Status dashboard: Status Dashboard

Control dashboard: ![Control Dashboard]()

Home Assistant automations can be simply written to control when the battery is charged and how much it is charged - e.g. if the forecast for the next day is good, then only charge the battery 50% over night. I use an automation in Home Assistant to set the "Stop Charging SOC %" based on the next day' Solar Forecast.

I have built SolarPi to interface my Growatt SPH3000 with Home Assistant without relying on the Growatt web API or interferring with the Growatt Datalogger/WiFi dongle. That is to say the Growatt web dashboard and the Growatt ShinePhone app still work (as well as they ever did). My approach uses a standard serial port interface on the inverter in accordance with the Growatt Modbus Inverter RTU Protocol document v.1.20.

The RS485 port on the inverter must be available and not used by any other external device, i.e. there should be nothing plugged into it already!

I am running this code on a Raspberry Pi Zero W with an RS485-USB adapter (specifically this: https://amzn.eu/d/foIEFqZ, but others should work), I have the USB adapter plugged into the Pi using a micro-USB (male) to USB A (female) OTG adapter cable.

I have designed SolarPi so that the code is extensible to integrate other Growatt inverters and potentially other brands of inverter.

Changes

1.0.1

Installation

These instructions should get you set up with a connection to the inverter and the code installed. When complete you need to start the code in the next section.

  1. Optionally add a plug to RS485 converter (if you are using the Amazon item above, this needs an RJ45 plug adding in order to physically connect to the inverter).
    • The white and green wires (serial data lines) from the adapter need connecting to pins 4 and 5 of an RJ45 connector. These can be connected either way as the adapter will automatically detect polarity. If you find problems using pins 4 and 5, try pins 1 and 5 instead - they should be equivalent.
    • The thin wire gauge makes crimping a connector on difficult - getting a good crimp is hard, so I recommend chopping off an old ethernet patch cable and joining the two together.
  2. Configure the inverter to use the RS485 port for monitoring (these are the steps for the SPH3000):
    • Press and hold the OK key on the inverter for 3 seconds and release to enter the "Basic Parameter" menu
    • Press OK to enter the "RS485 Setting" menu
    • Press OK to enter the "Port" menu
    • Use up/down arrows to select "VPP" as the "Port"
  3. Install RaspberryPi OS on Raspberry Pi.
    • You may want to enable ssh access, set your username/password and setup WiFi before starting the OS.
  4. Update the OS installation (sudo apt update; sudo apt upgrade).
  5. Plug in the USB adapter and check that it has been recognised by running dmesg and looking for something like the following output:
[   33.890325] ftdi_sio 1-1:1.0: FTDI USB Serial Device converter detected
[   33.890766] usb 1-1: Detected FT232RL
[   34.332027] usb 1-1: FTDI USB Serial Device converter now attached to ttyUSB0

  1. Note the USB device that the converter has created, in the above output text this is "ttyUSB0", it may be "ttyACM0" instead. You will need to put this device path in the config file (options.json) later.

  2. Install node.js (I am using version 16.16.0).

  3. Download ZIP archive of this repository and unpack to a temporary folder (alternatively clone using Git).

  4. Either run the install script or follow/adapt the manual steps below to install the SolarPi code.

  5. Start solarpi for the first time

Install script

Run the install.sh script using the command line ". ./install.sh". I recommend you familiarise yourself with what the script does first (basically, it creates a solapi user, copies the contents of the folder to /opt/solarpi and installs a systemd service so that solarpi is automatically started on boot and can be controlled using systemctl).

Skip the manual steps below if you use this script.

Manual steps

Follow or adapt these if you don't use the install script.

  1. Add a new user to run solarpi:
    • sudo adduser --system --group solarpi
  2. Make a folder to put the code in:
    • sudo mkdir -p /opt/solarpi
  3. Copy the code and change the permissions so the new user can run it:
    • sudo cp -r . /opt/solarpi/
    • sudo chown -R solarpi:solarpi /opt/solarpi
  4. Change directory to the /opt/solarpi folder and install the node.js dependencies:
    • cd /opt/solarpi
    • sudo -u solarpi npm install

If you want solarpi to run automatically at boot do the following:

  1. Install the systemd service file and enable it:
    • sudo cp solarpi.service /etc/systemd/system/
    • sudo systemctl daemon-reload
    • sudo systemctl enable solarpi

Configure SolarPi

Edit the file /opt/solarpi/options.json to provide the following:

Starting SolarPi

Now test solarpi installation at this point by running it:

If you've used the install script or followed the manual steps and installed the solarpi systemd service, you can either reboot or run the following to start the service after you've finished testing:

Use the following to monitor the output of the service:

and then to stop the service (if you need to):

Uninstall

If you have used the install script or followed the complete set of manual steps, solarpi can be removed totally by following these steps:

Development

If you make improvements, find bugs (in the code or this doc), let me know and, time permitting, I'll try to fix.

Updating Node.js versions

Earlier versions of SolarPi were developed for Node.js version 16.16.0. The version of Node.js that is now recommended on the https://nodejs.org site is 20.9.0 - version 20.x.x will be maintained to 2026 according to the Node.js schedule. I have updated my version by doing the following:

Rolling back to the previous version should be as simple as repeating the steps subtituting the relevant tar.xz file.

To do

Feel free to use this code for your own purposes. If you test this with a Growatt SPH inverter, please let me know, also if you add support for other inverters, I will look to merging changes in. I can't promise to provide tonnes of support, but will try to help.

Disclaimer

Whilst these instructions and code use published open interfaces and standards, you use the instructions and code at your discretion.

License

ISC License

Copyright 2023 David Brown

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.