put the hall effect sensor unit on the house battery bank power line
negative or positive,
attach the sending unit to the bank positive and negative for power and voltage sense
the display goes anywhere inside that you mount it with power to supply it
the display does need 5v only and uses a USB plug for that 5v
the display wifi connection is built in, NO other wifi is needed, its automatic
one system is all you need for your bank, you want to measure it , use, charge it as one bank, not as individual batteries
i'm going to mount it near the power panel/fuse box
i'm going to get 12v to 5v usb circuit board about $3, to use power it and connect that to Dc power
the voltage will 'sensed' at the battery NOT at the power panel