Power calibration for SCT-013-000 split coil current sensor (transformer)

[rodajc]

So a friend of mine gave me a Sonoff Pow Power Monitoring Switch Module.
As it is rated 10 A it wasn't up for the job of measuring the total home power consumption which can peak upto 9 kW or so.

The solution was to use an SCT-013-000 split coil current sensor (transformer) and clamp it on the cable to the distribution panel.
Therefore the 1 milliohms resistor was replaced by a 1.5 ohms resistor parallel to the current sensor.
Calibrate power. Job done. Works.
I was a bit surprised not to find any example of this anywhere, but anyway.

There is one issue though. Approx. 0.25 A is missing. This is the equivalent of 57 W. I assume that the current sensor doesn't detect currents below a certain level because of the magnetic characteristics of the transformer coil.

No problem. Before logging the energy consumption I add 24*57 Wh "manually" to the total for that day.
This way an unbelievable accuracy of +/- 0.4 % is achieved compared to what the energy supplier charges for.

Now, I wonder if Tasmota is able to take the 57 W into account straight away. This would be applying an offset to the whole
graph rather than fine tuning its slope as is done with the Power Monitoring Calibration procedure. Right?

Your thoughts?

[rodajc]

Here are a few pictures to make the description easier to digest.

First the SCT-013-000 split coil current sensor (transformer) clamped onto the cable going into the distribution panel:

Then the modification made to the Sonoff Power Monitoring Switch Module, i.e. the new current measurement resistor:

And finally the Sonoff Pow Power Monitoring Switch Module connected and mounted: