Is it valid to measure the voltage of a psu using a wall power monitor

Trying to figure out if the psu’s I bought from comgrows amazon return bin are actually 24 volts. By using a wall outlet wattage monitor and the hold_current value its appears to be in the 12 volt range. Is this a valid method to verify voltage for a psu or am I missing something.

Maths: tmc5160 hold_current:1, 4 active stepper motors idling with power, wall outlet says 35 watts, should be around 90 watts… I think.

Reason: Building a heavy high speed printer and before I go back to the design board want to make sure of the root cause.

No, this is not a valid way to measure output voltage on a PSU. You need a multimeter.

What do you want to measure? I agree with jakep_82

“Maths” What do you mean by that?