Measuring Power Consumption of AC Input With Off Grid Inverter at No-Load

To avoid the power inject to Grid in SUB mode, we need to withdraw small power from AC grid continuously. But due to the input current detection tolerance, different units may have different result. Hence, some inverters may withdraw 100W some may just withdraw 50W and some inverters just get 0W power withdraw.

But we would also like to inform you that there is no AC grid power withdraw under SBU mode.

5Amp from AC grid does not mean 5 x 230Vac = 1150W. The input power factor is very small under this condition, the actual power consumption in watts is very small due to the input power factor is very small. You could find the explanation in attached photo for reference.

Power quality measurement AC-Grid input as back up to support off-grid solar inverter

Your meter simply measures a very very poor power factor with a lot of apparent power, so there is no active power of 1150W, it is apparent power so you do not get charged !

Input active power = Apparent power * Power Factor

= (223.5VAC * 2.45Arms) * 0.0816

= 547.57VA * 0.0816 = 44.68Watt