30% less measured energy as supplier during a year

    Our house has a single phase supply. During the last year shelly EM measured only 2600 kwH consumption in the same time the supplier measured more than 3600 kwH. It is hard to find out what is the source of this big inaccuracy, and how could it be improved? The wire from current transformer is short to avoid unwanted induction and noises. The power factor is never over 95% even if I connect 3kw resistive load. The wire through the current transformer is a standard 10 sqmm copper. ( probably makes no difference)

    What should I try to improve the measurement accuracy? Improve power factor determination ? Or the current measurement?

  • Tmorm 18. August 2022 um 08:50

    Hat den Titel des Themas von „30% less measured energy as supplier“ zu „30% less measured energy as supplier during a year“ geändert.

    I just got an EM and noticed similar terrible accuracy compared to the real meter. I’ve configured the Shelly for the 120A clamp that’s connected and located it in various places, tried to isolate it from other cables but it is still roughly 10%+ too low also. This is compared to the real meter and another clamp meter. I have a suspicion the Shelly is not at all calibrated for 240V or I’ve been unlucky and got a dud. I also see negative PFs and low values, but this is just a domestic setup with nothing significant. I’m doing a full day meter comparison and if it’s still significantly out it’s going back.