Help Required Uploading Growatt Inverter To PVOutput


I would love to see the Modbus spec he used. First I noticed he is reading the first 100 registers in a single read. The documentation we have explicit says inverter will not answer to that, for sure newer models have upgraded spec. He also removed the upper nibble calculation from power, not big deal since most small to medium installs will never reach such a high power. He sure have two arrays because he sums the voltage of vpv1 and vpv2, I did not care for a second array. He takes the inverter temperature from register 97, our documentation says this register is Grid Fault Record 2 (daily | hour)

So, clearly, the modbus spec went through revision for those newer models.


No I don’t believe it does, here is a manual for it:

And here is a picture of mine:

Not sure how to connect the inverter to the RPi w/o an interface port? :thinking:


According to the manual there is a com port (L page7 of the manual).
In your case this port seems to be occupied with the blue cable. Is this cable connected anywere?


It goes to my switchboard to a “SDM230-Modbus” meter.


Then you are probably able to connect a cable attached to an RS485 to usb (costs about 3 euro plus the cost of the cable like the blue one) to the modbus meter (where the blue cable is connected) and get both the data from the inverter and the meter using a pc or a raspi or even a cheap orangepi zero (with armbian). Is this bidirectional meter used for the inverter only or also for the grid energy?
You will need to adjust the modbus parameters of the meter if the installer has not done it already (i.e. Modbus ID: 2 if the inverter has id:1, Baud rate 9600, Parity: NONE, Stop bits:1). All these parameters needs to be the same on both the inverter and the meter except the id.

Edit: you can even use your router to get the data if it has usb, it is using Openwrt and you are able to use ssh
Edit2: Ask your installer for the current use of the meter before changing any parameters. Though as the connection is done by the installer the parameters are probably adjusted already.



Same model a friend’s parent had installed recently.

As per manual, your blue cable might be connect to pins 2, 7 and 8 of the eastron SDM230. And your monitor software (aka RPi) shall be connected to pins 2, 3 and 4 (page 34 item 7.4). If those pins are going to some other place, let us know also.

You will need a rs485 to USB adapter as @lampra mentioned. I had success using those: -> very simple, look and feel very cheap but worked on my ABB Uno for debug purposes and also on a Eastron SMD630a. Does not require ground (pin 2 on the diagram page 34 of your manual). -> while bare open it has (it least it say it has) TVS protection that is a bonus for areas with high lighting activity (where I lived in Brazil). You need a USB cable (USBA -> usbB connector, common on printers). This is the one I most used. -> just for the records, those also works really well. Although I used them connected to arduino/esp8266 boards, they can theoretically be connected to serial port of an RPi. But is too much external components to take care if you have the USB ports on an RPi. Go for the USB.