SunPlanner started with a practical problem. I had paid for a solar app on Android. When I switched to a backup iPhone, the purchase did not transfer, and the replacement apps I tried did not give me enough reason to pay again.
I built my own web app instead. It was called Skoolie Solar, and it was the first app I finished.
What system was I trying to plan around?
My setup uses a 3.3 kW rooftop solar array and four 12 V, 300 Ah batteries wired as a 48 V, 300 Ah bank. It is a larger system than many mobile setups, but the daily planning problem is the same. I need to know what the panels may produce before I decide how much power to use.
A generic weather icon does not answer that question. I need an energy estimate built from the configured array and the conditions ahead.
What did the first app teach me?
Once I used Skoolie Solar day to day, I saw the next problem. A forecast could be useful and still miss the way my own setup behaved.
I wanted the app to compare its prediction with the production I recorded. The goal was not to claim that the app knew every loss in the system. The goal was to let the forecast adjust when a consistent gap appeared in the real history.
Why did calibration become the center of SunPlanner?
Calibration gives the app a way to learn from clean comparisons. After three usable readings, SunPlanner can begin applying the learned factor to later forecasts. The history keeps building toward 25 usable readings and continues updating after that.
That makes the estimate more personal without pretending that the phone measures the panels. SunPlanner still produces a forecast. The production value comes from the user at the end of the day.
What did SunPlanner become after that?
The app grew around two planning jobs. The Dashboard and Outlook estimate solar production across sixteen days, including today. Sun Finder compares the sun path with panel direction for a place and date.
Those tools help answer different versions of the same question. What can this system reasonably plan around before the day, the weather, or the next campsite makes the decision harder?
What has not changed from the first version?
The reason for building it remains simple. I wanted a solar-planning app that I could use with my own system and improve from my own production history. SunPlanner is the version of that idea available on Android today.