Using an ESP8266 ESP-01 module and an Arduino Pro Mini 3.3V I wirelessly update all outputs from my thermostat to here for data analysis and because it's cool.
This requires a voltage divided rectifier since thermostats run at least 24 VAC RMS.
Historical PV Battery Voltage and Net Power draw. positive current number means the net current is out of the battery system. A negative number means more charge from PV cells into the battery than the battery load is requiring.