I am creating a battery bank of six - 100 amp 12v batteries in parallel and am contemplating using a copper, steel or aluminum bar as a busbar to connect all the batteries together, one negative and one positive. This is mainly because the bank is in a mobile environment and I want to add rigidity to the pack. How do I determine what size (in2) the bar needs to be? Example: if the bar is 1" wide how thick should it be?