Thread: Alternator Fusible Link(s)

Originally Posted by SyntheticShield

That is a good point. But the best one could do I imagine would be to install a fusible link again (4 wire gauge sizes smaller, and would see to defeat the purpose of the alternator rewire to a degree) or some type of inline fuse able to handle the current, but the only place I could think of getting such a thing would be from an audiophile shop or something like that and even then I dont know if they would have them big enough to handle full load of the alternator.

It would almost seem more sensible to put in a automatically resetting circuit breaker or something like that.

If you can get a circuit breaker, that is great. I just use a maxi-fuse, although I will most likely find a fusible link when I get the time. The alternator is rated at 110A, so a 125A maxi-fuse should suffice:
Fuse, 125 amp, 32 VDC, Mega Fuse
You can find them at parts stores. Mine is actually a higher amperage, again do to availability at the time. This is the same setup I have run on another car, along with many other folks, with no issues. The fuse has always done its job.

To be fair, the absolute correct way to do it would be with another fusible link. Fusible links are "better" at protecting the circuit overall, without the potential for blowing under instantaneous spikes like fuses or circuit breakers. I would recommend something like this:
* Fusible Link

My opinion is that the best option is to include the listed fusible link with the alternator rewire, then remove the stock wiring from the circuit. I know that everyone says to leave the stock wiring connected, but that is going to be harder on the system...just like running two 8ga. wires in parallel is not the same as running one 4ga. wire!

You can go to the battery section of the parts store and find an assortment of length 4ga. wire that has eyelets on both ends. I went with the shortest I could find, because I made the routing as direct as possible, as at the time I was not considering rewiring the alternator. It cost me $5, then another $5 for the maxi-fuse. It is not tucked away as neatly as the alternator rewire "mod" but it is functional. My 2¢.

Originally Posted by JoshMcMadMac

If you can get a circuit breaker, that is great. I just use a maxi-fuse, although I will most likely find a fusible link when I get the time. The alternator is rated at 110A, so a 125A maxi-fuse should suffice:
Fuse, 125 amp, 32 VDC, Mega Fuse
You can find them at parts stores. Mine is actually a higher amperage, again do to availability at the time. This is the same setup I have run on another car, along with many other folks, with no issues. The fuse has always done its job.

Well I guess I stand corrected. I dont know why I thought they would not make fuses in that high of a rating for automotive applications. Thank you for that find piece of information.

Originally Posted by JoshMcMadMac

I know that everyone says to leave the stock wiring connected, but that is going to be harder on the system...just like running two 8ga. wires in parallel is not the same as running one 4ga. wire!

FINALLY!!! Someone that gets it. Ive got my harness completely out of the car and I intend on fishing that sucker out of there (the stock alternator wire) and I have, from day 1 of installing the alternator re-wire, left the OEM unconnected and taped up.

You are just chock full of good info, keep up the good work and thank you for sharing.

Originally Posted by JoshMcMadMac

I know that everyone says to leave the stock wiring connected, but that is going to be harder on the system...just like running two 8ga. wires in parallel is not the same as running one 4ga. wire!

True, but running a 4ga and a 8ga is better than just a 4ga. The reason being that current travels on the surfaces of metal conductors and one 4ga has more surface area than two 8ga. A 4ga plus a 8ga has the most surface area of all. Simple laws of parallel circuits. Besides, electricity will take the path of least resistance which will be the new wire. The old wire being there or not doesn't change anything as long as your new wire stays the same gauge and length. I deal with issues like this all the time when re-wiring the B-52H ECM systems.

Originally Posted by SyntheticShield

FINALLY!!! Someone that gets it.

I don't want to sound harsh, but his perception is a little misled. Comparing adding the rewire to changing out two 8ga with a single 4ga is apples to oranges.

Compare a 4ga to an 8ga with a 4ga. That's what the alternator rewire does, and you will see lower overall circuit resistance with the combined setup. Parallel circuits at work.

This is actually the basis of your whole car's electrical system (and any electrical system). Closing a circuit (headlights for example) is just adding a parallel circuit to what was already on (your fuel pump for instance). The overall system as a whole now has a lower resistance (more parallel paths to take) and that results in more current. Current = load.

Voila.

Originally Posted by SyntheticShield

FINALLY!!! Someone that gets it. Ive got my harness completely out of the car and I intend on fishing that sucker out of there (the stock alternator wire) and I have, from day 1 of installing the alternator re-wire, left the OEM unconnected and taped up.

Fishing it out is not the word for it. Be prepared to disassemble the wiring to get it out. There is electrical tape around the wires, then the wire loom is taped over that! If it is out of the car it should not be too difficult, just be prepared to remove and replace a fair amount of tape.