Duh, the alternator only puts out so many amps, which while you are running are partially being consumed by the engine as well as the blower..etc, so the wiring to the bank only needs to be sized to handle that load. It does NOT need to handle 300 amps unless you are running Grants alternator setup. My system has an alternator that is rated to 95 amps so it doesnt matter if my system can draw 300 amps, I dont need to run 00 wire to my battery bank near my amps. 4 gauge is plenty. From the bank to each amp is 4 gauge so I save money...Its simple ohms law people...oh maybe that is too difficult for some to understand. Maybe you will understand this then, "so many other people on here told me I need 00 wire so that is what I'm going to do, oh yea and If I dont do what Johnny says my boat is going to catch on fire"...
Engineers dont build stuff from hearsay they figure out with formulas and science.
Someone please explain to me how an amp setup that can draw 300 amps will pull that from an alternator that is only capable of 1/3 that, thereby requiring wire 3 times what is needed? The current will come from the bank which hopefully has been charged prior to this and will be helped along by the alternator. I count 4 people who are lemmings and know nothing about ohms law.