Big 3 Installation Question

[Speedfreely 10+ year member]

I need some guidance on one aspect of the Big 3 installation. I'm OK with the Battery Neg to Chassis Ground, and also the Chassis Ground to the Engine Block. However, when I inspected the wire that goes from my Alternator to my Battery Pos, I see that it travels through my fuse box and it also seems to be wrapped up in a shrink wrap of plastic and other wires are also being ran inside this shrink wrap. I have a 93' 3000GT and the fuse in the underhood fuse box is rated at 120 amps. I also notice that there is a wire that goes from the Pos Battery terminal to the starter. My starter is rated at 110 amps. What I need to know is this.

1. Do I need to run the wire from the Alt to Pos Battery through my fuse box? Or can I just just install directly from alt post to battery post and install an in-line fuse, if so, what size fuse do I use for 0/1 gauge wire?

2. If I can run a wire directly and add an in-line fuse, will that screw up my fuse box? Will I have power running to everything still....not sure of the flow of power through the fuse box(where it comes in and where it goes out)...I'm thinking it gets it power from the existing wire that runs from the alt to the battery. I'm hoping I'm mistaken and I can perform this mod without messing with the fuse box. Please help! Let me know if you need anymore detail.

3. Can I use any of these 0/1 gauge wires I find for amp install kits? Or is there some other type of wire I need to use? Where is the best place online to purchase wire?

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[forbidden 10+ year member]

Run a new line direct from the alternator to the battery. This line MUST be fused. Look at the ampere rating of the alternator, there is generally no need to go way far beyond that. Yesterday for example we did a overhaul of this very line after the line had dead shorted due to heat melting the insulation. The fuse did it's job, thankfully there was a fuse installed on this line. Using our clamp meter, the alternator even though it was rated at 70 amps in this GM vehicle, was putting out 96 amps as the battery had been depleted, thus the draw was greater. I could not have fused this line with a standard AGU type fuse, instead a 130 amp wafer fuse was used which was more than adequate for both the demand and the supply over such a short distance.

What is important running the lines as this customer found out is that the layout of the lines is important. Take great care to run it away from any heat source and ensure that it is adequately tied down. If you have some 0 gauge left over from a amp kit, there is no harm in using it.

 

[Decipha 10+ year member]

i never fuse the alt to batt

 

[Speedfreely 10+ year member]

Thanks for the info, but what do I do with the wire that is currently connected to the alt and pos battery post? It is bundled with a bunch of other wires and it runs through my fuse box. Do I just wrap the hell out it with electrical tape or shrink wrap tubing to prevent a short??

 

[ravendarat 10+ year member]

Can you disconect said wire from both the destination and the source. If you can then you can simply tie it up at each end and not think about it anymore. Obviously removing and recovering the remaining wires would be best but you can do what I said as a secondary move.

 

[Fast1one 10+ year member]

i never fuse the alt to batt

Explain why

 

[Speedfreely 10+ year member]

Really, I can add, not replace? SWEET! You mean leave the wires be and simply have two wires comming off the positive alt? One original and one new (1/0gauge) fused to the pos battery terminal?

 

[johnecon2001 5,000+ posts]

if you can just leave it there. A new 1/0 gauge AND your stock wire will allow more flow than just the new 1/0 gauge alone. If possible simply ADD to the wire, not replace.

Finally, someone who said the right thing.

Leave the stock wiring in place! Just add that new piece of 1/0awg to it. Fuse that wire. Max current draw through 1/0awg is 350A, although for the Big 3, I usually fuse somewhere around 200-250A.

Any 1/0awg wire you find will work, even that found in amp kits.