How accurate is IotaWatt with the ECS25200 clamps on main lugs? I’m trying to understand the actual measurements after installing an EVSE. When the EVSE (Emporia) and the car are both reporting ~8.8kW-9.1kW (240v, 40A limited), and I look at IotaWatt, I see more like an increase of 5-6kW measured on the main input wires of my panel. One of these is obviously incorrect - and I wouldn’t be shocked if EVs are lying about actual current, but that seems like a lot. I don’t have a clamp meter to verify independently - something I will have to rectify, but then of course I don’t know its accuracy either.
They should be within 1% but are you sure they are 200A:50mA? Those clamp type come with tabs of paper between the mating surfaces that usually fall away when you install them. Check to be sure they did and that the surfaces make good contact. They will read low if not. Also, look at the power factor. It should be very near 1.00 for EV charging. A low PF is usually a sign that the clamps are not seated properly.
Thanks - I think the PF aspect is the key here, as I’m seeing more like 0.9 when I’m looking at this. It’s not the paper between the clamp tabs, but I suspect something is wrong with them. They’re the ones from the kit, so they are 200A:50mA.
The electricians who replaced my generator ATS had mixed all the CTs up randomly on me, I wonder if they also ran load through these with them disconnected and maybe damaged them without killing them.