Alternator fuse?

ZmOz

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I'm going to be replacing the stock ~100 amp alternator in my Jeep with a 165 amp. That means the crappy 8 gauge alternator cable has to be replaced too. It would be so much easier to just use a peice of 4 gauge cable and no fuse.<br /><br />Do you guys think a fuse is really necessary? The only time I could imagine it would ever blow is if the cable shorted out somewhere, but that's no different than the starter cable which doesn't have a fuse...
 

dolluper

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Re: Alternator fuse?

Should aready have a fuse in your fuse box for alto, 4 guage wire with a fuseable link would work<br />Fuseable link looks like wire, but get the right guage that goes with #4 wire for added protection<br />Your starter should have fuseable link at solinoid hook up bolt running to alto
 

ZmOz

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Re: Alternator fuse?

There's already a fuseable link in the alternator cable, but of course it would blow with the upgrade to 165 amps. I already have a 200 amp Mega fuse I could use, but I'd have to spend $20 on a holder and it would just add unnecessary voltage drop if I don't really need it.<br /><br />My battery cables are custom 2/0 and there is no fuse of any kind, but it didn't have any fuses from the factory either.
 

dolluper

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Re: Alternator fuse?

Don't think the fuseable link will blow unless the starter shorts,then the alto is protected,your voltage regulator will control your charging rate no matter want amp you use.Her's some stuff from one of my other posts<br />If too much current goes through a wire, it can overheat and melt. The amount of current that a wire can handle depends on its length, composition, size and how it is bundled. Let's take a quick look at how each of these properties affects the wire's current-carrying capacity: <br /><br />Length - Each type of wire has a certain amount of resistance per foot -- the longer the wire, the larger the resistance. If the resistance is too high, a lot of the power that flows down the wire will be wasted; the energy lost as heat builds up in the wire. Ultimately, heat build-up limits the current-carrying capacity of the wire, as the temperature must not get hot enough to melt the insulation. <br /><br />Composition - Automotive wire is usually composed of fine copper strands. Generally, the finer the strands, the lower the resistance and the more current the wire can carry. The type of copper used has an effect on the resistance of the wire, too. <br /><br />Wire gauge - The wire gauge, or size of the wire, also determines how much resistance the wire has. The larger the wire, the less resistance. The smaller the gauge, the larger the wire -- so a 16-gauge wire is bigger than a 24-gauge wire. Wire gauges go all the way down to zero, which is also called 1/0 (one aught). Even bigger than 1/0 is 00 (2/0, or two aught), and so on. The diameter of a 4/0 (four aught) wire is almost half an inch (1.27 cm). <br /><br />Bundling - The way a wire is bundled affects how well it can dissipate heat. If the wire is in a bundle with 50 other wires, it can carry a lot less current than if it were the only wire in the bundle. <br /><br />When a high tension electricity passes through a cable it builds up a surrounding electril field that frees oxygen into the surrounding ai r and it forms OZONE this OZONE attaches to rubber and will make rubber detearoriate
 

petryshyn

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Re: Alternator fuse?

no fuse needed<br /><br />Just curious why you are upgrading the alternator?
 

ndemge

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Jul 15, 2002
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Re: Alternator fuse?

I had a 160 amp alternator on my van, I had 2' from the alternator to the battery, so used a piece of 1/0 strait to the battery. (1 wire setup)<br /><br />I probably should have had something in there...but didn't.
 

ZmOz

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Re: Alternator fuse?

Originally posted by dolluper:<br /> Don't think the fuseable link will blow unless the starter shorts,then the alto is protected,your voltage regulator will control your charging rate no matter want amp you use.
That's exactly why I don't think I need a fuse. The alternator can't possibly put out more than 165 amps even if something is wrong, so I can't think of any situation where the fuse would blow other than a shorted cable.<br /><br />
Originally posted by schematic:<br />Just curious why you are upgrading the alternator?
At 207,000 miles I don't trust the original one anymore. :D All the local parts stores only carry a rebuilt 90 amp for over $110 + core, even though my stock alt is over 100 amps. I got a rebuilt/rewound 165A on ebay for $105 with no core. Plus my Odyssey battery was laughing at that poor old worn out stocker. :p
 
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