I always check my recorded energy values from the Tesla app to compare with my Pepco billing period values. Going backwards on the 21st of January with the Tesla app for my PV system returned something very strange for the 18th of January. Here's the data:
Home Solar PW-from PW-to Grid-from Grid-to
Initial recorded 19 Jan: 14.3 2.7 9.1 0.5 0.1 0.1
First time from 21 Jan: 9.3 2.7 7.2 0.5 0.1 0.1
Later time from 21 Jan: 10.7 2.7 8.5 0.5 0.1 0.1
Today - 24th: 11.3 2.7 9.1 0.5 0.1 0.1 <---- NEW
I record the previous day's values the following day (Initial in above). On the 21st I was going through the values to get to the Pepco billing period for January and I recorded the values for the 18th of January (First time in above). I was surprised that the values did not agree with what was recorded on the 19th. After reaching the start of the Pepco billing period I went back for another look at the values for the 18th (Later time in above). I was extremely surprised that I now had a set values for "Home" and "PW-From" that were different each time.
Also, from the Pepco bill: from the grid = 150 Kwh and to the grid = 2 Kwh. Whereas using the Tesla app: from the grid = 130.7 Kwh and to the grid 17.7 Kwh. This is the first time that there is such a large difference between Pepco and my recorded Tesla app values. The values usually agree within a few Kwh.
Update: I have a whole house backup with two powerwalls to handle the 60 amp circuit for my wall connector. All the components are under my car port.
Update 01-24: The thing I really don't like is why this strangeness happened on the 18th of January and all the other days were OK. Are these values calculated or simply retrieved from a database?
The same thing happened today January 24th for the 21st. The values: original 12.1, 19.6, 8.4 15.7, 0.1, 0.3 new 13.0, 19.7, 9.2, 15.7, 0.1, 0.1