To get the most from your cheap 100W solar panel you may need to add significant extra cost for a MPPT controller and even a solar tracker. This project is here to propose a VERY VERY cheap solution : - a mostly 3D printed frame to hold your flexible panel - a fully working 20A MPPT controller (hacked hardware) + ESP32 firmware + Android App - a lead acid and lipo smart charger (1s, 2s, 3s or 4s) - a voltage controlled power supply (3V - 16V) - a fully automatic sun tracker (hardware and software) to get the max power from your panel All this with an incredible price ? Less than 55$ ? (panel not included !) Well ... seems impossible... let's have a look !