I have a need for a circuit for an Arduino project. I need to monitor amps/volts for three sources. They are all "12V" but that's only theory. A solar panel array of about 220 watts peak can go as high as 19V without load. The charger and "12V" battery can go as high as 14.8.
I want to read the Volts on the solar panel and the amps currently being used. This can be up to 19V and 20 Amps. Amps should never be negative.
I want to read the volts at the battery, and the amps going into the battery (+) or coming out of the battery (- amps when discharging).
Not required, but nice to have, would be voltage and amps going into the load. The voltage really can't be different than the battery voltage. Amps may be higher than what's being pulled from the battery because it could be getting at least part of the power directly from the solar panel.
I would like to connect this sensor module(s) using I2C for simplicity. Because everything is powered from a battery, I would also like to be energy efficient. Low quiescent and/or shutdown ability.
My design used three Adafruit INA 219 breakout modules. That failed and I realised that the (explitiv deleted) charger module had a common positive rail (solar panel, battery and load). Connecting the INA219s to a common ground resulted in smoke signals of course.
I would prefer a design that I can build myself and to do that the design requires none or very limited use of SMD chips.