DIY Arduino MPPT Solar Buck Converters: Harvesting Free Energy!

Harversing free energy? Sounds like bullshit? Well, it isn’t completely free. You have to buy solar panels and some electronics DIY gadgets. Then you have to invest a couple of hours to build it. The rest can be found on my GitHub: What can these MPPT (Maximum Power Point Tracking) buck converters do? - Supplied by the panel voltage, can&drain your battery during the night - Input voltage 15 - 22V - Output voltage 1 - 14.4V - Suitable for lead acid batteries and 18650 lithium cells (via TP4056 charger for example) - Simple MPPT solar charge controller for 18V solar panels - Sparkfun Pro Micro 5V, 16MHz or 3.3V, 8MHz (3.3v recommended, more efficient) - ACS712 current sensor on the output side - Voltage dividers for voltage measurement on panel and output side - Working frequency 31.5kHz - 3 operation modes: MPPT, Constant Voltage, Constant Current - Status indicator LED (different blink codes) - Output current 3A (limited in software) Synchronous model only: - Two N-channel Mosfets, driven by IR2104 half bridge driver, inductor (synchronous buck converter) - Common negative topology - SD card data logger for time, voltage and current. You can import the txt files in Excel and make fancy diagrams - 0.96“ OLED display for V, A, W, Wh and status - Output current 3.8A (inductor rating, the rest can do much more) I’m using these controllers to charge all our USB gadgets. The energy is stored in a DIY 18650 power bank with 8 cells and two TP4056 chargers in parallel, so the...