Hardware for Energy Monitor and PV Diverter advice please

Hardware emonPi
1

I have a PV installation (type 2 wiring) and would like to setup an energy monitor (emoncms), and energy diverter.
EmonPi seems to be ideal for the monitoring, however I notice it only has 2 inputs for CT.
Since I also want to divert unused PV-generated power, I’ve been looking at the diverter- it’s unclear to me whether the diverter needs to be a wholly separate unit based on EmonTX, or whether it’s possible to get energy monitor functionality (emoncms) and the diverter, from one EmonTX unit.

Thanks in advance!

2

Nobody has done an energy diverter using only an emonPi, without looking at whether it has the necessary output to drive the triac, I couldn’t tell you. (I don’t have time to check and do the sums now - if you’re interested I can do so, but it will be a few days.) But only one CT is required for the diverter function, so the second would monitor the PV output. What you wouldn’t have is a direct measure of the diverted power/energy. Is that why you’re worried about having only two CT inputs?

There are two proven designs based on the emonTx, which I assume you’ve seen, but you cannot have the functionality of emonCMS in the emonTx alone, it needs far more processing power. So if you did the diverter function with an emonTx, you’d still need the emonPi to run emonCMS.

3

Thanks, I was only concerned that I was missing a trick somewhere and might be spending more than I needed to!

4

I’ve now got emonpi working well, so I’d like to get energy diversion sorted.
Do I need any extra components to reprogram an emontx? And what’s the best type of emontx to use for diversion please?
Thanks

5

See the articles on the main website, under Learn→PV Diversion→Introduction

You’ll need a programmer and lead, and a copy of the Arduino IDE.