Hardware needed for 3 Phase PV Monitoring

Please could someone recommend what I could use to monitor a 3 phase system with PV?

I would like to monitor our electricity usage in the building, and our PV generation so I can identify how much of our PV we are using, and how much is going back to the grid. I also hope to adjust times we run our appliances to make better use of the PV.

I thought a EmonPi and a EmonTx with 6 clamp meters would work, but some of the other posts I have looked at suggest that you need a EmonTx per phase… which seems a bit excessive!

Many Thanks


It does depend on what kind of accuracy you are looking for. If you download the 3-phase sketch for the emonTx and read the explanation in the comments, that should give you some idea of what the problems are. Certainly, to read real power (which is what you’re charged for), you’d need one emonPi (or emonBase) and two emonTx’s (one on the grid connection, one on the PV infeed). If you’re content with apparent power (VA) only, then you could get away with one emonTx and one emonPi. If you want best accuracy, then 3 emonTx’s it must be.
Alternatively, look to one of the alternative designs that are mentioned in these forums, but those may involve a greater or lesser degree of construction and assembly by yourself. (e.g. ESP8266 WiFi power monitor)

Don’t forget that your meters can give you some data, but it’s “historical” in the sense that you only get to know that energy has been generated or used in discrete chunks after the event (see the front of your meter for details).