So, have a DYI board. Initial testing showed the readings were quite off (tested with 75w and 100w Incandescent bulbs).
Initially used a very small VT, upon reading I understand that quality matters here. Official supported ones with shipping cost a fortune over here, so though would try out something that local shops have. Went out and bought the heaviest 230->9v they had (open type, weighs 0.9 pounds)
But it does not seem to have improved: 100w reads as 111 and 75 reads as 85.
Voltage calibrated with cheap voltmeter I have and by looking at mains smart meter made for solar - both showed ~ 231-232v
CT used for testing were HWCT-004 (one with very short wire, another with extended about 6 feet) and SCT013
So before I go and splurge on official VT - can there be something else off - like my soldering, PCB quality, esp board, reference shunt (I used LM4040B25FTA which says 0.2%) ?
Ok, so I guess multiple things going on, one of them be not being an electrical engineer.
It seems that my power supply is actually not that great. Replacing with simple usb charger and adding two 6.3v 4700u capacitors in parallel reduced the idle amps measured on CT from 0.1 to 0.01-0.02 ( still fluctuates just as var)
I also decided to check how much actual watts is that 75w lightbulb - by leaving that only on and looking at the 250$ mains meter which was installed with solar (so guessing that should be accurate).
Surprise for me - 83w, 0.36A. I guess i need a better multimeter
So with the power supply changed I get 83w in iottawat, PF is 0.99 (still 0.01 short to 1) and amps are off by 0.01. But I guess that’s the best I’ll get
the only thing that still does not align is the vtphase (command?vtphase=1). Description on this forum says it should be negative while mine is positive and fluctuates quite a bit (0.2-0.5)
