I’ve noted that the instantaneous power readings differ between my EVSE and the eMonPi. This is particularly noticable on the Solar Divert app, as if I set it up to have the EVSE power feed as the divert feed, it will colour the EVSE measured draw separately.
What I see is that the amount of power increase measured at the eMonPi is higher than what is measured at the EVSE. So when the EVSE switches on, there’s an increase in power which isn’t account for. It’s of the order of a few percent. I’m wondering if there’s a voltage drop due to long cabling, but there isn’t a voltage feed to compare (or have I missed it?).
Should I expect the two to agree with each other accurately? Is one expected to be more accurate than the other. Can I calibrate the EVSE figures to match the eMonPi?