Hi, I installed a emontx v3 with wifi and 3CT+temp, AC-reference+DC supply around the beginning of Jan and connected it to emoncms online to visualize the data. But the measurements are not making sense. Just to give some basic numbers:
Service: 25A 3Phase
5,4kw EV charger (2-phase combining into 1-phase)
9kw (3-phase) Heatpump
2kw EVSE charger (1phase)
5,5kw PV (Facing east, south-east)
- Top power usage is lower than expected.
- Looking at the graphs in emoncms, I would expect 5kw+2kw draw normally at about 17:00 CET as the total system draw at least. (PV generation is minimal (below 100w) during this time), but I see only about 3,5-4kw max, spread over 3 phases. I charge one nissan Leaf that’s depleted until 20%, and one completely depleted phev.
- The heatpump cycle shows as negative for one phase.
- I think I’ve identified the heatpump cycle, but two phases show the draw as positive, and one phase show it as negative with the same load profile (ie visual representation of the load, only inverted). If I reverse the CT on that phase, I get a proper representation of the heap pump draw, but the normal load on that phase is 500w negative, showing exported power during night time, which is impossible. (see attachment)
- The PV production should visualize as a 3-phase banana
- Currently one of the CT’s is inverted in regards to the current flow indicators on the CT, and the PV production is reasonably represented as a 3-paralell banana. (see attachment). But if the current indicators are facing the same way, one of them indicates an inverted power curve during PV production times?
I must have done something wrong. Does it matter which order the CT’s are connected to the emontx? Something related to phase shift?
I checked the installation instructions again, and while the fit is tight (rigid thick cables), there’s play and not forced. I’ve changed the dip switch to use DC for power.
I’ve also tried to replace the CT, since I had one spare, no change.
Could it be calculating UK power, like 120v or similar? Could explain the lower calculated power than expected.
I used a fairly low end clamping clamping current meter to check the current on one of the phases, and it seemed to be accurate.
Measured [email protected], 3*256/1,71 (=449w, which at the time showed approx 495w locally. The square root of 3 was off the top of my head so it was off by 0,02.
Any help welcome.