I have noticed this issue before but yesterday i took the time to take some screenshots. My solar system is mounted facing east so i have a lot of production in the early morning. The solar forecast for the next day seems to be accurtate the day before. But on the next day the forecast shifts to a south facing production shape.
This causes DESS to predict no production in the early hours. So when my PV starts producing this will go straight into the battery instead of being exported for the high peak morning price. The next planning cycle DESS will notice this and quickly sell it back to the grid. Often at a lower price and we will have lost ~20% because of efficiency losses.
Realised solar production on 07-04-2026 at 17.26
Forecasted production for 08-04-2026 on 07-04-2026 17.26
You can see a similar forecasted PV shape as realised production.
Forecasted production for 08-04-2026 on 07-04-2026 20.24
You can see a similar forecasted PV shape as realised production.
Forecasted production for 08-04-2026 on 08-04-2026 06.46
The forecasted PV shape shifted to south facing production
Forecasted production for 08-04-2026 on 08-04-2026 07.34
At this time PV is being generated but because of the forecast is it being stored in the battery
Realised and forecasted production for 08-04-2026 on 08-04-2026 08.14
Here you can see what happened between 07.00 and 08.00. Energy that was stored in battery was later exported to the grid.
Realised and forecased production for 08-04-2026 on 08-04-2026 11.37
You can see the realised and forecased PV shape change back to the east configruation that i have.
