[WSSix]

I designed my own system. It's similar to the Mad Electric one. I have a 2 AWG cable going from the battery to a Ford style starter solenoid that's mounted behind the battery. Then the battery cable goes all the way to the front. It's only live during cranking. The ground goes straight to the frame rail after coming off the battery.

The alternator return is 4 or 6 AWG and goes all the way back to the battery through a 100 or 150 AMP circuit breaker that's also mounted behind the battery. Yes, the alternator cable is live the whole time. However, you can't easily put a circuit breaker/fuse on the starter cable so protecting the alternator cable is easier and smarter IMO. Something goes wrong and the system is disconnected and the car is protected.

I have a junction post on the firewall for power take off to the rest of the car. It's below the AC box between the frame rail and firewall essentially. It's well protected and a pain to get to if needed. I also have a smaller circuit breaker right off the post for the rest of the car. It's much smaller than the alternator one and protects the wires between the junction point and fuse panel in the interior. The electrical fans have their own circuit breaker and relays mounted to the inner fender on the driver's side. Off hand, I believe that's the only power circuit not going to the inside.

My attitude towards more circuitry is to not play games with protection. You have to protect the wires to what their capable of handling. I could have eliminated the circuit breaker off the junction post on the firewall and allowed the circuit breaker in the trunk for the alternator to handle it. However, it's a big breaker. The wires off that junction post could melt before they trip the circuit breaker in the trunk. An inexpensive and small circuit breaker is money well spent IMO.