Street Rat

I'm in the process of putting a sound system in my 1981. I'm upgrading the positive wire from the alternator to the battery. I'm using 1/0 size wire. I want to add a fuse in the line near the battery.

I have read numerous posts over the last few hours. Some people say to size the fuse according to your alternator output. I have a 100 amp Power Master unit installed. Other people seem to be of the reasoning of sizing the fuse according to the size of the wire and it's capacity to flow current.

So my question is what size fuse do I need? I have an ANL fuse holder and will be using an ANL fuse.

Thanks In Advance,
Craig

markcz

A few feet of 1/0 can handle well over 300a, so....

Without the stereo, how many amps can just the CAR pull under max load?

What size fuse will you have from B+ to amp?

Add them together, tack on another 10-50%, and there's your answer

Street Rat

The amp will be fused with an 80 amp fuse. If I assume that the car can pull all 100 amps out of the alternator at any given peak. That would be 180 amps plus another 50% would be 90 amps. So that would be 80 + 100 + 90 = 210 amp fuse.

Am I on the right track here?

markcz

Right track, yes, but 180+90=270

I'd think either a 200 or 250 amp fuse would be fine. If the alt is rated for 100a max, then it prob won't ever get close to 200a unless there's an issue.

Street Rat

Thanks for the quick responses and correcting my math also.