I have an arduino and I would like to measure the voltage on the engine battery 12vdc and the backup battery 12vdc and the trolling motor battery bank 36vdc. The 2 12v batteries are in parallel. I planed on powering the arduino from the house battery, and monitoring all 3 banks of batteries. Also I will make sure the grounds are shared in each bank. The arduino will controll a relay to feed power to the voltage divider network to monitor voltage, then open the relay as to not discharge the battery all the time.
I have found some info on which resistor values, capacitor and diodes to use on 12vdc batteries but I would like for advice on the 36vdc setup. It will be charging at approx 14.4v per battery or 43.2 volts.