I bought a Carnetix power supply and the optional wiring kit that came along with it. The wires for example the power wire that is connected to the battery is small I'm guessing 18 guage wire. Shouldn't the power cable that needs to be connected to the battery be around 4-10 guage? I searched but couldn't find a definitive answer on this. If this wiring kit cable is so small how is it to be hooked up to the battery. If anyone can enlighten me it would be greatly appreciated...thanks.
It doesn't need to be a big gauge if it will only draw 5amps (60W at 12V), which BTW is what the carnetix PS is rated for
The +12V and GND wires in both J1 and J2 are actually 16GA. The are fairly short and are meant to be used as a splice point for the longer wires coming from your battery. You should use a larger gauge wire from your battery (10-12GA should be fine) to prevent having too much of a voltage drop during cranking. Since the J1 and J2 wires are short, they will not affect the voltage drop much during cranking.
FYI...during cranking, if your CarPC is drawing 5amps, the battery will actually be supplying almost 10 Amps to the PSU!!