DeCoupe: do you need two batteries to start? Maybe only in the Frozen North? To assess batteries we need to compare apples to apples. PHCA is not the same as CCA or RC, but for me in a warm climate it sounds like the spec to use as it most nearly addresses the starting load. My coupe battery tray is tattered and visibly unsafe, though my batt hasn't dropped out of it yet, so I'm interested here. Welding wire has more and smaller strands and is better suited for carrying high-amperage loads, but we're starting cars over a few seconds, not pushing arc-welding amps for a minute or more at a time. That said, I used the multi-strand wire back in my '02 days. Battery wire can be sourced at marine supply stores as well as welding shops. Prices, wire gage and number of strands vary. Wandering a bit, I'm thinking about ground-side current distribution. What might be the effect of battery grounding in the back of the car? The current running back to ground, highest during cranking, will disperse throughout the metal body structure. Is there an appreciable galvanic effect to thus charge the body?