I currently have two 12v100Ah in series to my Multiplus2a/2000/120V . I am upgrading to four 12v100ah LiFePO4 batteries in a 2p2s configuration. The SmartShunt manual doesn't seem to cover where to connect the Vbatt and Aux wires for a mid-point configuration. Would this be correct? And if so, I suspect that the mid point voltage would not be for each battery but rather for each two series set, right? Side question: Do I really need busbars?