When I installed solar equipment on my home, I bought all the panels and an obsolete but functional inverter from a solar company I used to work for. Ya, it was cheap, but unfortunately the inverter didn't have any monitoring or logging functionality at all. I looked at a few commercially available systems, but all of them had features I didn't need, and none of them had logging features I liked. So, I set out to make my own using a Particle Photon, a microcontroller in a neat 24-pin DIP package with native wifi capability, and the great Open Energy Monitor libraries. Now this thing has been running flawlessly for 4 years on the original prototyping board which looks very bad, so I decided to build a 2nd generation unit with a neat printed PCB from PCBWay, and a few added features like motion sensing backlight for the display, and better connectors for the MCU, display, and input connections.