question

NOT an expert here but...

As far as I am aware your basic GX setup is only capable of integrating a limited range of Modbus meters that it 'understands' how to communicate with and which registers in those devices are pertinent.

If scanning, under Modbus TCP/UDP menu, isn't finding the Shelly then it isn't supported, which I suspect will be the case.

It is absolutely possible to create/build a gateway that has the Modbus characteristics of a supported meter and gets its data from somewhere else. You could do that using NodeRed, although you will not be able to do it on the Cerbo if it is already running its internal Modbus server.

See ... Shelly integration Nodered - General - Node-RED Forum

Hope that helps...

Cant you run Large OS on your Venus... Therefore Node Red, easier and better than mucking about with Modbus registers directly. Details... Victron doc.

passing data between Node red instances is easy, Google that.

You can also enable Modbus on any GX and control the GX relay/s directly. Contrib_Modbus will allow you to interact with a Victron system from any NodeRed instance but I don't think you can write to any registers that would show up as a meter.

That said... If you were using a current sensor as a load monitor, in any role, you would be using a tank/voltage input to read it. If you actually connected something like THIS which NodeRed can easily drive, you would be controlling the load reported to the GX with your HA instance and sending the Shelly data to it. If you wanted to drive a Modbus RTU module over Ethernet then look at THIS , or similar.

The gateways are great, cant comment on the analogue IO I linked but at that price I will be getting a couple to mess with.

On you HA server NodeRed instance, you could build a flow that responded as if it were a compliant meter and populate it with the Shelly data, then just point the GX at it. It would even work over Serial with an RS485/USB dongle, linked to that flow, would then look like a compliant meter to the GX.

Less bits, MUCH more work but may be better than a simple current sensor input, it depend on your application and I don't use either so can't usefully offer an opinion on the differences.

Hi, not much time. But this: https://github.com/freakent/dbus-mqtt-devices is your friend. With this you can create "Virtual PV Inverter" or "Virtual Grid Meter"... after that they will show up in Victrons MQTT Server and then you can write values into it like that: W/123fs456fhge/pvinverter/<id virtual pv>/Ac/Power . Good luck!

Others have already shared community made libraries that will work much easier. However here's a victron one in case you're interested. This is installed on venus os by default

However I believe it's written to only work with one ct and either grid or pv out the box.

However I imagine it's an easy fix to add a second one. You'd essentially an indentical copy of this to venus os and just change the device ID's to prevent conflicts and then also the below line in meter.py

d = data['params']['em:0']

to be

d = data['params']['em:1']

(I've not tested this but might be useful)

GitHub - victronenergy/dbus-shelly: HTTP based driver for Shelly energy meters to be used on VenusOS

@dougle03 Easy, I was able to do this last week with same Shelly and setup as you:
(easy, but it took me a while to be able to figure this also eheheh)
https://github.com/Goaheadz/dbus-shelly-em-smartmeter
This is my fork from other projects. (forget all instructions from readme..I didnt had time to edit it)

First understand and try to log with SSH to your system (root acess)
If you already comfortable in accessing Venus with putty per example, then go for my fork above.
- You need to make 2 installs. One for the grid and another for the PV inverter.
- Better to make a fork for your self, rename and edit files as needed.
(you will change "goaheadz" from commands bellow to your github user link)
- Grid should be in clamp 0 and PV in clamp 1
- Edit config.ini for different name and instance name for each clamp
- Use dbus-shelly-em-smartmeter.py for the PV and install
- Then use dbus-shelly-em-smartmeter_grid.py (rename it removing _grid, change config and install again)

Be carefull with this.
You can use the code bellow for install one of the clamps, but for the second one you should use diferent directory name

Clamp1 (after choosing correct py and config file):

wget https://github.com/Goaheadz/dbus-shelly-em-smartmeter/archive/refs/heads/main.zip
unzip main.zip "dbus-shelly-em-smartmeter-main/*" -d /data
mv /data/dbus-shelly-em-smartmeter-main /data/dbus-shelly-em-smartmeter-grid
chmod a+x /data/dbus-shelly-em-smartmeter-grid/install.sh
/data/dbus-shelly-em-smartmeter-grid/install.sh
rm main.zip

Second Clamp:
wget https://github.com/Goaheadz/dbus-shelly-em-smartmeter/archive/refs/heads/main.zip
unzip main.zip "dbus-shelly-em-smartmeter-main/*" -d /data
mv /data/dbus-shelly-em-smartmeter-main /data/dbus-shelly-em-smartmeter-pv
chmod a+x /data/dbus-shelly-em-smartmeter-pv/install.sh
/data/dbus-shelly-em-smartmeter-pv/install.sh
rm main.zip

If everything goes ok you should have shelly clamps in venus:

It may seem hard, but if I was able to do it..you will also.
G.