Solar powered weather station based on a ESP8285 board and a few sensor. Use a 75F 5.4V supercap as energy storage. Target to be as low power as possible.

Here are voltages from a series bank of three parallel trios of 400F, 2.7V supercapacitors regulated by an MSP430 to balance and stay under 7.3V. They are charged from a 5.2W, 9V solar panel.