I have installed a Air/Air heatpump/AC in my countryhouse 75km´s from home. I wanted a remotely controlled SmartPlug to monitor the power usage of the heatpump/AC.
It has worked VERY well!
Until I got a feeling that the powerbill was larger than expected? The only power used there is the Wifi extender (that hooks up to the neighbours WiFi connected fiber Internet), two Nedis cameras, a D-link camera and three smart plugs (for the cameras) and this Nedis WIFIPO120FWT smart plug for the heatpump/AC. And thats it! no other appliances that draws any power from the net. And the cameras draws a few watts..
So I was confused that the powerbill was some 51% higher than what the heatpump had used according to its smart plug?
But I had the answer right in front of me, when checking the stats of the powerplug every now and then.
Sure thing, 1,772 A x 213,7 V = 379 W … NOT 235 W !!
The fault is off by a factor of 1,6, which pretty much is the difference between the recorded energy of December 63 kWh compared to the bill for December, saying 95 kWh or 1,51 times what the smart plug logged.
Could any body else using this smartplug verify this as a systematic fault, or is it just my unit that is faulty?
Could it be that the power plug measures the power as Amps and Voltage in phase, however the pumpmotor is an inductive load, thus drawing a higher reactive power than just the resistive?
To be of any value, the powermeter must measure the way the electric company is billing, right?!
**********update*************
I have gathered logs over time, it does not seem to be any pattern in the fault of the calculations? I will report this to Nedis-support and hear what they have to say?
