Plugged in to a storage facility 110 GFCI outlet.
1. My EMS is hard wired to the coach with remote display reading L1 -125, L2 -124; Inverter/Charger remote panel in the coach shows unusually high reading of
L1 -136, L2 -133.
2. Moved to a different 110 GFCI plug and the readings were as normally expected (ie) EMS remote display L1-127, L2-125; Inverter/Charger remote panel reading
L1-128, L2-126.
Understanding the EMS monitors incoming power in both cases what could be the cause for the Inverter/Charger to kick up much higher as in the first case here? and with similar input in the second case, normal readings. There was no power drawing appliances running in either case.
Check the outer you plugged into and then the second one with your multimeter and see what they say. Odd that you got different readings. I know the reading on the voltage panel is different then my progressive bu the progressive is the correct one.
Voltage readings are a relative difference in potential, not an absolute measurement.
There is most likely a wiring quality issue with the first outlet - probably a loose neutral or ground. You did the right thing changing plugs; I would recommend letting the facility know of the problem.