I have had my emonpi up for over a year now, I got a EV last week and installed a OpenEVSE, I have the AC-AC adapter that is offered with the emonpi, I have not paid a lot of attention to the vrms value until setting up the OpenEVSE, looking at the last year the vrms has recorded the voltage as between 110.4 and 114.5V, I was expecting the OpenEVSE to show 230V it however shows 240v with an occasional fluctuation to 239 or 240v I used my multimeter to read a outlet and it was showing 122v so I am wondering what I need to adjust to make sure that the emonpi gets the voltage accurately. right now the emonpi is showing vrms as 113.1v about 9 lower than than the multimeter
240 Volts is correct. The values 220 and 230 Volts are holdovers from long ago, as is 110, 115 and 117 Volts.
You’ll find that it’ll vary between 240 and 245 with short excursions as high as 250.
Performing the calibration procedure should bring the emonPi numbers in-line with your multimeter measurements.