Quick update on the calculation of the daily PV yield based on the numbers which can be retrieved from the integration/Modbus TCP:
I have been in contact with Huawei support on how to calculate the PV yield to match the numbers in Fusionsolar. They have confirmed that the formula
PV yield = daily yield from inverter + battery day charge – battery day discharge
is correct to calculate the PV yield as a raw figure. However, the calculation of the PV yield in Fusionsolar is slightly different, because they also include the energy consumed by the inverter. So the Fusionsolar formula is:
PV yield = daily yield from inverter + battery day charge – battery day discharge – energy absorbed by inverter
Based on this I tried to reverse engineer the Fusionsolar numbers and found the following: The closest I get to the Fusionsolar numbers is by using the formula and when the PV is producing energy (and only then!) subtracting approx. 0.11 kWh per hour for the energy consumption of the inverter. The energy consumption of the system when the PV is not producing, is already covered by the fact that the battery discharge number is typically higher than the increase of the daily yield from the inverter, resulting in a negative PV yield number. So those negative PV yield numbers are correct from a total energy produced/consumed point of view. Of course, if you don’t like to see the negative values then just set the result to 0 whenever the calculation leads to a negative number. This is also how it’s done in Fusionsolar.
If replicating the Fusionsolar numbers is not that important, then just use the first formula to get the raw numbers and then the inverter consumption (during the times when the PV is producing energy) will be included in your total energy consumption.