This seems like a googleable question, but I simply cannot come across anything.
I'm working on a 12v system (aluminum boat), trying to supply power to a motor 12ft away from the circuit breaker. Through online sources, I was able to determine that at the 45amp max, 6awg wire could handle it, with a 5% voltage drop.
The confusion enters when I try to calculate the voltage drop with this 6awg wire, plus the potentially 8awg wire that runs 1.5 feet from the battery to the circuit breaker.
How does one correctly calculate the voltage drop over two different gauged pieces of wire?