There are several tools to calculate battery backup time, solar panels and structure calculation, Compass to find right direction for panels installation as well as solar tilt angle meter to find accurate angle of structure.
Solar App Tools are;
✅ Battery backup time calculator
✅ Solar tilt angle meter / bubble level
✅ Solar compass
✅ Find current location (Latitude/Longitude)
✅ AC wire sizing
✅ DC wire size calculator
✅ Total load calculator
✅ Solar area calculator using google maps