So, the question you should ask is which car battery cable size is suitable for a 12-volt power supply? Ideally, a 6 gauge cable is the best option for a 12-volt power supply. This automotive wire can sustain a maximum of 60 volts and is ideal for 12-volt electrical systems.
What size marine wire do I need?
The ABYC recommends wire conductors of at least 16-AWG (gauge) for lights and other similar equipment. That's minimum, and heavier gauge isn't much more expensive — and generally no more trouble to install. We suggest you use 12- or 14-AWG to minimize your voltage drops, or more if the manufacturer suggests it.
What size are standard battery cables?
Ideally, a 6 gauge cable is the best option for a 12-volt power supply. This automotive wire can sustain a maximum of 60 volts and is ideal for 12-volt electrical systems.