Calibration changes the relationship between SunPlanner’s prediction and the real production history you enter. It does not add a new weather forecast, measure the equipment, or promise one accuracy level for every system.
What does calibration learn from?
Each usable reading pairs two numbers from the same day. SunPlanner keeps the uncalibrated prediction that was saved for that date and compares it with the actual solar production you enter.
The difference becomes part of the calibration history. The app uses that history to adjust later predictions.
When does calibration start changing the forecast?
Calibration begins affecting the forecast after three usable readings. A usable reading needs a positive prediction and positive actual production for the same day.
A blank entry, a zero value, or a day without a comparable prediction does not move the calibration factor or the progress count.
Can I use production records I already have?
Yes. If you have eligible daily production records, you can add past dates instead of waiting for every reading to happen after installation. The app still needs a comparable prediction and production value for each usable day.
Existing history can help the calibration profile grow sooner. It does not mean the forecast becomes fully tuned from one entry or on the first day.
What does calibration leave unchanged?
Battery capacity does not change predicted solar production. It remains part of a separate battery-gain estimate.
Calibration also does not calculate tree height, obstruction shade, wiring condition, or the cause of a repeated loss. It learns the size and direction of the gap in the production history without pretending to diagnose the equipment.
What does the 25-reading marker mean?
Twenty-five usable readings mark a fuller calibration history in the app. Calibration begins earlier and continues updating after that marker.
The marker is not a universal accuracy promise. Weather, seasonal coverage, data quality, and the system itself still affect how closely a forecast matches the final result.
What should I log?
Log complete end-of-day solar production when SunPlanner has a matching prediction for that date. Keep logging across different conditions and times of year. The most useful history comes from clean comparisons between what SunPlanner predicted and what the panels actually produced.