Protection for Alternator Charge Wire

[annularnos]

I'm adding an alternator charge wire directly from alt to starter relay. Is it better to use a fusible link, Maxi fuse, or no protection on the alternator charge wire?

[Cudaragtop]

I used a #8AWG with a #12AWG fusible link. Crimped & soldered and heat shrinked.

A couple of different articles on the subject.
http://www.madelectrical.com/electricaltech/amp-gauges.shtml
http://www.allpar.com/fix/alternator.html

[Chryco Psycho]

The problem is you will have power at both ends of the wire so where do you install the fusable link ? I suppose you could fuse both ends ?

[GoodysGotaCuda]

I used a blue sea systems marine type circuit breaker in my alt output. Nice ring terminals and easy to reset if something hiccups. Unlike a fuse or fusible link.

[annularnos]

The problem is you will have power at both ends of the wire so where do you install the fusable link ? I suppose you could fuse both ends ?

This brings up a good point....what exactly are we trying to protect and what are we trying to protect it from? Is it the battery, the charge wire, or the dash wiring? Are we protecting from a short or excessive amperage from alternator?

[crackedback]

I do only the end at the starter relay.

To me the major risk is if the car is parked.  Linking the starter relay side removes battery from the circuit if it lets go.
 

[annularnos]

I do only the end at the starter relay.

To me the major risk is if the car is parked.  Linking the starter relay side removes battery from the circuit if it lets go.
 

I agree. However,you now have two fusible links in the system. The one you added and the factory fusible link on the red wire going to the bulkhead connector. Everything is looped together assuming you left the factory wiring in place. The smaller factory fusible link will likely blow first, rather than the likely heavier charge wire fusible link that you added. So, what are you really accomplishing? Perhaps I'm missing something???

[burdar]

If you run a jumper wire from the alternator to the starter relay, AND you leave the existing wire on the alternator stud, you are now feeding the interior with two wires instead of one.  The factory red wire(interior feed) is protected by a fusible link.  The black wire coming off the alt is not.  I would add a fusible link to the black wire coming off the alt.  That way, both interior feed wires have protection. I would add the fusible link right at the alternator. The only reason you would install a fusible link(or two) to your jumper wire, would be to protect it from a dead short.  If you route that jumper wire away from any moving parts and keep it separate from the rest of the harness, I think there is very little chance of a short. Adding a fusible link on both ends of the jumper wire wouldn't hurt anything.

[crackedback]

The stock system uses a fusible link in the charge line.  You are bypassing that and should consider some sort of protection in the new alt. 

[annularnos]

I was so focused on the additional charge wire that I forgot about the Mad Electrical mod. Not only am I doing the Mad Electrical mod, I am also adding the additional charge wire. So now there will be 3 fusible links in the system. One added on the additional charge line, one added on the redirected factory black alt charge wire, and the original existing factory link for the red wire and the other half of the black factory wire. Sound like a solid plan or am I missing something.

[crackedback]

That's what I would do if you are using fusible links.

[Aracer]

I think the fuse-able link is there to protect the interior from the battery in case of a short, that occurs in an accident that crushes wires to the frame. The extra links "probably", will increase available amperage.
     I also think that the amp meter that never goes over the 50 amp line, shows that the car needs no more than 75 amp. alt.
     I upgraded where needed, but still run the amp meter and I have a new volt meter to swap into my 1968 cuda. On my 74, I just put a thicker alt. wire (75 amp) and extra  fuse-able link wire to the interior amp meter, for now.
  I have some relays for the lights to play with. That's a good idea too.

[dodj]

This brings up a good point....what exactly are we trying to protect and what are we trying to protect it from? Is it the battery, the charge wire, or the dash wiring? Are we protecting from a short or excessive amperage from alternator?

IMO, it is the battery. HUGE amount of instantly deliverable power.I use a MANL fuse at the battery for the charge wire from the alt. Or use a cct breaker like Goody did.

[annularnos]

If I do the Mad Electrical mod and install an additional direct routed charge wire, any reason I can't remove the factory alt charge wire altogether?

[burdar]

The Mad article has you removing that wire from the alternator and splicing it right into the existing fusible link on the red wire.  Either remove it from the alt and splice it into the factory fusible link OR just add an extra fusible link to that wire and leave it hooked up the alt stud.

I have a brand new harness so I don't want to do all that cutting and splicing.  That's why I'm keeping the wire attached to the alternator.(I'll just add a fusible link to it)  You are still feeding the interior with two wires witch is taking a lot of load off the bulkhead connector.  I'm also using relays for the headlights.  The bulkhead connector won't see much load at all.  I see no reason to bypass the bulkhead connector if the harnesses/connections are new AND relays/jumper wires are used to take the electrical load off of it.