I'm installing a BMV-712 in my RV. I have two 12v batteries connected in parallel. I was going to connect both battery negative wires to the "Battery" post on the Victron shunt. But, the quick start guide shows the negative wires from each battery going to opposite sides of the shunt. The quick start guide referred to the second battery as a starter or auxiliary battery. In my case, it's neither of these. My question is do I connect both negative battery cables to the "battery" side of the shunt or one on each side of the shunt?