[scottz]

It depends on your cabling. The only difference between the two setups is the resistance in the cable between the battery negative terminals. Otherwise the two points are electrically the same. I use 1/0 cables; you would need a high dollar meter to measure any voltage drop across 12" of 1/0 cable with a nominal amperage draw.

I know, there is a lot of info out there implying that one of the batteries might not get charged correctly. But really, there is no electrical difference in those two drawings.