Fusing a HO alternator?

[Supergumby5000 5,000+ posts]

My HO alternator comes in next week, and i'll want to install it asap. I hear some people fuse theirs, and others dont, so im j ust looking for reccomendations on whether to have an inline fuse or not.

Also, what size of fuse will i need? I was going to to just guess a 250amp fuse considering the HO alty is 250amp, but then i got confused when i realized my amplifier has TWO 250amp fuses.....

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[95BlackGA 5,000+ posts]

Fuse to the size of wire, not to the current draw. I.E. Don't fuse 4ga with a 250Amp fuse, use a no more than 100Amp fuses.

 

[Supergumby5000 5,000+ posts]

Fuse to the size of wire, not to the current draw. I.E. Don't fuse 4ga with a 250Amp fuse, use a no more than 100Amp fuses.

i'll be running 1/0ga, not 4ga.

 

[Supergumby5000 5,000+ posts]

okay i just did some searching, and it sounds as though i dont really need to fuse the power wire between the alternator and battery as long as i still have my stock connections fused. Does taht sound right?

I have the big 3 done right now non-fused, but i've also never had any experience with a HO alternator.

 

[95BlackGA 5,000+ posts]

okay i just did some searching, and it sounds as though i dont really need to fuse the power wire between the alternator and battery as long as i still have my stock connections fused. Does taht sound right?
I have the big 3 done right now non-fused, but i've also never had any experience with a HO alternator.

It'd be worth it to fuse it, it would prevent possible engine fires. Worth the money, but not necessary. I don't even think my stock wiring was fused from Alternator to the battery.

 

[Supergumby5000 5,000+ posts]

It'd be worth it to fuse it, it would prevent possible engine fires. Worth the money, but not necessary. I don't even think my stock wiring was fused from Alternator to the battery.

okay, let me see if i can figure this out. The fuse is present to prevent the wire from recieving more current than it can handle, which could result in melting/fire/trouble.

Where im lost is my amplifier has two power/two ground inputs, with a reccomended fusing of (2) 250amp ANL fuses. so, in other words, the amplifier could technically draw more current than the connection between my batt and alternator. IF i was to fuse the alt to battery, there would be lower limits than from the rear battery to the amplifier. wouldnt that cause problems there too?

 

[Supergumby5000 5,000+ posts]

okay, from what im reading, it wouldnt hurt to fuse the wire.

I have an extra ANL fuse holder with a 250amp fuse. Will that be sufficient for this scenario, or should i go ahead and order a 300amp fuse? im not sure what kind of draw to expect with two kinetik2400's, a kinetik800, and 4200RMS

 

[Supergumby5000 5,000+ posts]

ttt

 

[Anniku989 10+ year member]

Your supposed to fuse it so incase it melts (the casing on the wire) that it won't spark/arc and catch stuff on fire. If you don't run it by the radiator, headers, really hot things, etc. And you can safely run it in a place where you feel confident it won't melt from anything, go ahead and leave the fuse out.

 

[01 S 10 10+ year member]

Your supposed to fuse it so incase it melts (the casing on the wire) that it won't spark/arc and catch stuff on fire. If you don't run it by the radiator, headers, really hot things, etc. And you can safely run it in a place where you feel confident it won't melt from anything, go ahead and leave the fuse out.

x2

make sure its secure and will not rub against anything hot. zipties ftw

 

[Anniku989 10+ year member]

Haven't had a fuse in the stock alt big3 upgrade for about 2 years now. Just check it every few weeks, or at least every oil change. I used an extra 2foot or so of 2/0, but i ran the wire around the engine bay up high, where its away from heat, and I can inspect if often

 

[audioarsonal 10+ year member]

I have never fused between the battery and the alt.Only on the run through the car,which is for safety only.

Not needed IMO

 

[jrwalte 10+ year member]

I also don't fuse the alt to battery +. I have it in a loom that resists heat and I ziptie it to secure it down. Always keep your wire secured 2-3 inches away from a heat source when loomed. I'd keep it 5-6 inches if not.

If you do fuse it, you can start with the 250. The most that can ever be drawn from this wire is what your alternator can produce, which is rated at 250 amperes. Most alts don't produce what they're rated for in real-world (heat, RPM speed, wire resistance, electrical demand all play a factor). Worse case, the fuse slowly burns and pops and then you buy a 300-350 fuse.

 

[MAY03TBLT 10+ year member]

okay i just did some searching, and it sounds as though i dont really need to fuse the power wire between the alternator and battery as long as i still have my stock connections fused. Does taht sound right?

No....the wire between teh alt and batt would still be an unprotected circuit

It'd be worth it to fuse it, it would prevent possible engine fires. Worth the money, but not necessary.

agreed....I did not fuse mine....as stated above, I made sure the wire was not routed near moving parts or sources of heat