Big 3 fuse question?

[heineck]

im doing the big 3 upgrade on my car in 4 AWG, from what ive been reading most people say the alternator to battery + line should be fused. but some people say to go by the ouput of the alternator and some say that if ur using 4 awg u should 150 amp fuse and for 1/0 to use 300 amps. so what should i use? if the stock alternator is only 105 amps, do i use a 100 amp fuse or a 150 amp fuse?

[cherrington17]

realistically... if you fused your line at 150... what in god's name is your stock alt doing to output that kinda power???

think about that for a second. Could it ever get that high to blow that fuse? you can and WILL get over 100A on the stock alt... so that one will blow immediately. You'd need like... 110


I have an aftermarket with 2ga. I never fused mine. Why? Its only going to the battery, and a battery can take a quick spike w/o exploding.

[robalero]

not to mention its already going to the battery without a fuse anyways

[heineck]

ok so no fuse then.

[Afugy]

Ummm I've never seen anyone, heard anyone, or ever thought of doing a fuse from the alt to battery. Anyway, you would need to fuse both ends... right, power can come from both ends. You just don't need a fuse, look at how all of the other wires in there live safely.

[heineck]

ok well all the big 3 stuff ive been readin said to. but i trust u guys so ill do it without. thanx

[clutch1]

Just don't ever let the wire touch the frame if you're replacing the alt or something... or just disconnect ground on the batt.. meh nothing bad's gonna happen if it isn't fused.

[Afugy]

I got some 4/0 from work to do my big 3 over.