Originally Posted by Redbear
This means you would get slightly more wattage charging a 12-volt bank from 36 volts rather than series-wiring the panels for 72 volts, assuming you can eliminate the losses in the wiring for twice the amps into the controller at the lower voltage.
Yes indeed. Here is a nice tool for cable sizing: DC Cable Sizing Tool - Wire Size Calculator - MM2 & AWG - solar-wind.co.uk
. I have used it for all major DC wire runs inside my bus. There are more accurate ones out there, but they are also more confusing. Go for 1% acceptable loss and you'll be golden.