Continuing the discussion from Open Energy Monitor Port:
Here is a design I made to monitor Power without the use of voltage dividers which are really flaky and don’t provide proper values . the I2C code is really simple
Good luck the design was made on KiCad
if you want the Gerber please send me an email ill send it to you and you can upload it to PCBway.com for board manufacture, $5.00 for 5 boards.