Initial attempts to use Eagle for CAD too successful. Decided to try Diptrace and this proved to be more intuitive, may be it's just my age!

Sketched out the schematic. Probably not the final design but will help prove the concept.

Settled on having four major blocks on the PCB. A Solar Charge Controller, a Boost Converter, an H Bridge Driver for the Solenoid and the ESP8266 Wireless Microprocessor. tot her with a suitable 3.3V Regulator and other supporting components. Most of the circuitry relies on the Manufacturers' design data and Application Notes. nothing really original.

Used the MCP73871 for the Solar Charge Controller (I had the Adafruit version so why reinvent the wheel), the TPS61175 for the Boost Converter , the BD6221F for the H-driver, the ESP826-07 for the Micro and a TPS77533D for a voltage regulator.

Now for preparing a suitable layout. Not as easy as you might think. Texas recommendations for the Boost Converter are a challenge