I wrote a solar power system designer for small-scale solar projects. It started as a PC Parts Picker for solar panels, but I added a simulator and a few other features focused on solar power.
Would love to know what you think about it!
edit: here's the link: http://tiny-solar.space/
Some takeaways I had playing with it quickly:
I think "Time of Day" numeric value display in the simulator is using "Day of Year" as the refresh requirement (remains static through progressing time, but will update if you manually change time or date).
The physical space display at the top of the simulator is cool, but difficult to see everything on mobile.
I like the power line diagram in the builder. Makes it very easy to understand how things would hook together.
Edit: spelling and some word changes for clarity.