high output alternator wiring?

Hi, I have some questions about wiring, and wiring with a high output alternators. Now I have a 4000 watt system and i am looking into high output alternators. Currently i have a 300A ANL fuse on my power wire (battery front to battery rear)(also have completed the BIG 3). But i got to thinking, is this fuse really protecting me? Im not sure exactly how it works but here is my worry :/ My alternator now is only stock (I think its about 70-80A at 2000rpm) so there could never be enough amperage to blow my fuse right? I thought that the fuse was there to protect? so i am getting a little confused. Also when getting my high output alternator do i only look for an alternator capable of 300A output? Or can i buy one that puts out less (like any where from 160-250A). And use the same power wire, I used for my batteries (mentioned earlier) capable of 300A.... or will it be pointless (using a wire with more amperage capability than my alternator)? thanks and i really appreciate any thing you can help me with!Lanzar car audio

A fuse protects the wire. You should have a fuse on each end of your battery wire, one fuse up front, one in the rear. The idea being that if the wire is shorted, cut, any kind of damage and has contact with ground, the fuses will disconnect the wire from the batteries. A battery hold several hundred amps, so it's not so much the alternator at this point. For the alt wire, it needs to be big enough to carry the max out of the alternator. For my 230amp alt, I was told 1/0 was a good choice. I have 1/0 going from the alt to a 250amp fuse to the battery. So if my charge wire is shorted while the engine is running I will have a problem, but if it shorts with the engine off, the fuse will blow and keep from melting anything else. For the charging side. I like to have plenty of head room. Your system is going to pull say 340amps at full power (more at peak times, and more for the inefficiency of the amp, but this is just a number to work with) and your car is going to need 65amps or so. Your total pull would be just over 405amps. The battery can pick up the slack, but your alt is incharge of refilling the reserve. As long as you use about 3/4 volume, a 300amp alt should handle it. But you don't have any headroom to grow with.

Thanks that explained alot, yeah i am new to car audio and just starting to learn about things like this, i dont go to comps. or ne thing so i never play it over 3/4 volume and i have 2 fuses between my battery because of an article i read on here lol. I am not going to be able to get my alternator until Christmas time (i am going to get one around what you have) do you suggest getting my 1/0 gauge wire now even though my alt. doesn't push nearly that much? (just kind of for the sake of replacing old wire and corroded terminals?) or will this make my alt. try to hard to push the amperage that the 1/0 gauge can handle? Im not sure if that's how it works, but if you could help me it would be appreciated. thanks- Love 12 Volt! best site ever!Lanzar car audio

The alt is going only push it max amps if the electrical system needs it. I don't see any problem in doing 1/0 now in prep for a big alt.

okay thanks! im get my wires now. and prepare to get a better alternator!Lanzar car audio