Ages ago I have bought the emonTx from openenergymonitor:
It is still running fine. Never had problems with this hardware.
Maybe in the mean time there is better hardware available on that site - that I don't know.
In my setup it is monitoring:
- 3 phases with 3 CT clamps
- solar power production with 1 CT clamp
- voltage
Regarding the voltage monitoring - I only need to plugin the adaptor of the emonTx in a AC power socket. So it is not only used to power my emonTx but also to measure the voltage of one of the phases. The voltage for the other phases can be estimated by adding a phase as you commented earlier.
The data is sent via 433MHz radio. To recieve this data I have also bought a RFM69Pi hat for my raspberry pi:
So the data is processed on my raspberry pi and sent to node-red via MQTT.
Regarding the software setup there is also plenty of documentation available on the open energy monitor site.
Here below a diagram of the components:
