I hope this is not a silly question to ask but I have 3 x 12v batteries wired in parrallel ( + to + & - to - ) where my multi-plus inverter has two positive leads & two negitive leads coming off two batteries. When I install my smart shunt ( If correct ) I put the two negitive leads coming back from the inverter on the ground side but would I put two leads on the other side of the shunt back to the batteries or just a single lead.