I have 2 magnum MSH3012M inverters. I'm installing 2 400AH lithium batteries in parallel and a Victron smart shunt 500A. I've created a diagram for the install. Is this configuration correct? If connecting both battery negative cables to the battery minus side of the shunt does that parallel the batteries or should I also have both battery negative posts combined as illustrated in the diagram below? ... Thanks! 
You should take all of the positives to the bubar, so batt1+ to red busbar, batt2+ to red busbar and +inv1 & +inv2 to red busbar. Then batt1- and batt2- to the battery side of the smartshunt. Then the load side of the smartshunt to the black busbar. All of the cables should be appropriately sized and the lengths kept to a minimum.to avoid volt drop. You don't need to link the two negative battery terminals as they are linked at the shunt.
