growatt-rs232-reader

This reader allows some Growatt Inverters to publish data on a REST endpoint and optionally MQTT topic.

Releases

1.5 - Fix DayProduction, improved HA discovery, added precision setting 1.4 - Support for Home Assistant, supported MQTT credentials

Usage

Usage: ./growatt -action string The action (Start or Init). (default "Start") -baudrate int The baud rate of the serial connection. (default 9600) -broker string Connect to MQTT broker (e.g. tcp://localhost:1883). -device string The serial port descriptor. (default "/dev/ttyUSB0") -server int The server port for the REST service. (default 5701) -topic string MQTT topic /solar//. (default "Growatt") -delay int Period (seconds) of delay to publish values on MQTT. (default 0) -user string MQTT user (leave empty to use unauthorized) -password MQTT password -precision int Number of decimals for sensor values (default no rounding) -v
Activate verbose logging

REST endpoint: what do you get?

Example output of http://127.0.0.1:5701/status:

{
  "VoltagePV1": 335.8,
  "VoltagePV2": 0,
  "VoltageBus": 380.6,
  "VoltageGrid": 225.7,                   *
  "TotalProduction": 3822.6,              
  "DayProduction": 0.7,
  "Frequency": 49.99,                     *
  "Power": 798.4,                         *
  "Temperature": 26.9,                    *
  "OperationHours": 1891.338,             *
  "Status": "Normal",
  "FaultCode": 0,
  "Timestamp": "2018-12-09T13:15:54.363021599+01:00"
}

Starred fields are optional and won't be included outside status 'Normal'. MQTT messages will only be send if a value changes (no additional information will be send).

Additional information can be retrieved using: curl http://localhost:5701/info:

{
  "Reader":"Reading since 14:11:18",
  "Interpreter":"Polling since 14:11:18",
  "Publisher":"Normal",
  "Init":"OK"
}

Above is a perfectly legal state as long as the times are within 10 minutes of the current time. Note that startup takes several seconds.

MQTT

As of version 1.4, Home Assistant Auto Discovery is supported as well as support for authentication. For Openhab, see below. Note that the Timestamp format has been altered between v1.3 and v1.4!

If configured, status attributes are published as separate topics. Info attributes are not published.

Status

Up and running with restarts in the morning. As power goes down (sunset) the interface of the inverter will reset, so the init needs to be resend as soon as the inverter comes back to life. This needs polling, as no sign is yet detected which indicates it is powered on again. Note that reading the serial port is blocking without timeout, so additional processes are started to check the communication.

How to build and run:

It is written in GoLang. For compilation, see the build.sh script.

Binaries for the Raspberry Pi and Odroid are available though.

growatt_pi2 : Older B models, Zero possibly
growatt_pi : Model 3(+)
growatt_odroid : C2 (maybe others)

Run as ./growatt --device /dev/ttyUSB0 --baudrate 9600 or without any arguments to use the default shown. Currently, stop bits, parity, etc. are fixed.

If you want to initialise the inverter manually, use ./growatt --action Init.

Required

You need a 'USB to serial' converter. Remove the little plate to expose the RS232 port and connect the cable. Connect the USB-side to a Raspberry Pi or other device. Using a Raspberry the serial output should NOT be activated (raspi-config).

Home Assistant

Make sure you have the MQTT plugin up and running. Discovery is automatic as long as publishing is to the HA-monitored server. For example, use https://www.home-assistant.io/integrations/mqtt

Openhab HTTP

If you would like to use this as Openhab growatt publisher, use this in combination with the HTTP binding: https://www.openhab.org/addons/bindings/http1/

In your services/http.cfg, add the following:

growatt.url=http://127.0.0.1:5701/status
growatt.updateInterval=5000

Create an items/growatt.items with the following content:

Number Growatt_PvVoltage       "PV voltage [%.1f V]"           { http="<[growatt:5000:JSONPATH($.VoltagePV1)]" }
Number Growatt_GridVoltage     "Net voltage [%.1f V]"          { http="<[growatt:5000:JSONPATH($.VoltageGrid)]" }
Number Growatt_TotalProduction "Production overall [%.1f kWh]" { http="<[growatt:5000:JSONPATH($.TotalProduction)]" }
Number Growatt_DayProduction   "Production today: [%.1f kWh]"  { http="<[growatt:5000:JSONPATH($.DayProduction)]" }
Number Growatt_Frequency       "Net frequency [%.1f Hz]"       { http="<[growatt:5000:JSONPATH($.Frequency)]" }
Number Growatt_Power           "Current power [%.1f W]"        { http="<[growatt:5000:JSONPATH($.Power)]" }
String Growatt_Status          "Status [%s]"                   { http="<[growatt:5000:JSONPATH($.Status)]" }
String Growatt_Update          "Updated: [%s]"                 { http="<[growatt:5000:JSONPATH($.Timestamp)]" }

Install the JsonPath transformation plugin.

Note that on power down of the inverter there will be values missing from the JSON, causing messages in the openhab log. As far as I know there is no way to indicate a field is optional for JSONPATH.

Openhab MQTT

Install a MQTT broker somewhere (e.g. Mosquitto on your Openhab system)
Install the MQTT binding
Install a Thing of type MQTT broker and configure for your server
Install a Thing of type Generic MQTT Thing and select the broker (note: this application does not support login to the broker)
Monitor if you receive messages (e.g. mosquitto_sub -v -t '#')
Add channels and items to the Generic Thing
Use as MQTT channels (the 'Growatt' part is configurable):

	/solar/Growatt/Power         
	/solar/Growatt/VoltagePV1    
	/solar/Growatt/VoltagePV2    
	/solar/Growatt/VoltageBus    
	/solar/Growatt/VoltageGrid   
	/solar/Growatt/TotalProduction
	/solar/Growatt/DayProduction 
	/solar/Growatt/Frequency     
	/solar/Growatt/Temperature   
	/solar/Growatt/OperationHours
	/solar/Growatt/Status        
	/solar/Growatt/FaultCode     
	/solar/Growatt/Timestamp

Disclaimer

No, this isn't production ready quality code. See License.

The init string for the converter is fixed.

License:

MIT

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

lemval / growatt-rs232-reader