alternator wires

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moparmat2000

moparmat2000

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Hi y'all,

I have a 50 A mini denso alt, i just bought #8 gage wire to run it to the battery. According to powermasters website 50A up to 105A across a 4 foot to 7 foot run requires a #8 gage cable. What i bought was marine grade fine strand OFC copper wire along with the crimp n solder terminals for the alternator end.

I am planning on running this direct to the battery + terminal, with a fusible link. I have made up a 12 gage fusible link approx 9 inches long. I have been told to go 4 sizes smaller on fusible links than the wire you are protecting.

The question now is, how will this smaller wire affect the efficency of the charging circuit? It has to be there to protect the circuit. Powermaster mentions using too small a wire in the charging circuit causes a voltage drop. This 12 gage fusible link chokes the circuit down.

The good thing, is that my 50A alternator is on the low end of the scale for the 8 gage lead, so at least i have room to grow alternator wise if i need to.

Thanks in advance.
Matt
 
They are talking about voltage drop due to small gauge wire on a long run. 12 gauge is correct for the link.
 
Thank you, i was concerned about that.

Nice thing is the 8 gage will allow me a heck of an upgrade in alternators should i ever need it.
 
You could also run a fuse. A lot of alternator upgraded wiring kits from painless etc. come with a inline fuse and holder.

Napa sells a fuse holder #BK7821143 that you could get a 60 amp fuse for. Much safer than a fusible link.

Ron Francis wiring Does not recommend fusible links and can be a source of fire.

Modern cars have all gone to fuses for protection.
 

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blown71duster said:
You could also run a fuse. A lot of alternator upgraded wiring kits from painless etc. come with a inline fuse and holder.

Napa sells a fuse holder #BK7821143 that you could get a 60 amp fuse for. Much safer than a fusible link.

Ron Francis wiring Does not recommend fusible links and can be a source of fire.

Modern cars have all gone to fuses for protection.
Click to expand...

X2 on using a fuse instead of a fusible link. The factory used links because they were cheap. By the mid 1980's they finally came around and started using fuses. Fusible links are kind of maybe they will or maybe they won't devices.

I would bet a #12 gauge link would not melt on a 50 amp alternator output unless the alternator totally shorted to ground and the battery was being dumped back through it. Chrysler used a #16 gauge link on 45 amp alternator circuits and even they didn't always melt in time to save the wiring.
 
KitCarlson said:
Nice picture.
Click to expand...

I should have added that was a picture taken off a article about wiring tips and their quote with that picture was :

"Prevent Fires

Many racers and enthusiasts are still in the habit of installing a fusible link, as those are what had previously been provided by the OEM’s for years. Old habits die hard in the performance industry, and fusible links are no longer an accepted way to wire a performance vehicle. “Have you ever seen one of these things light off? There’s a reason why they are not used any more. Consider a Maxi Fuse,” he says.

As seen here, a fusible link is a poor choice when wiring a vehicle. RFW’s Scott Bowers suggests Maxi fuses instead to handle larger current loads."



That was enough for me to use fuses to protect everything , I would not personally use a fusible link .









.
 

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Ok, i'm all ears. What should the recommendation be for a maxifuse in this alternator circuit? Is there some sort of chart online i can use to calculate this.

If i am to remove the stock fusible link out of the body harness. It is a 16 GA link attached to a 12 GA red going back to the battery. I would assume Maxifuse here as well? This is the batt hot that feeds the body harness. I dewired my ammeter and tied the 2 leads together.
 
moparmat2000 said:
Ok, i'm all ears. What should the recommendation be for a maxifuse in this alternator circuit? Is there some sort of chart online i can use to calculate this.

If i am to remove the stock fusible link out of the body harness. It is a 16 GA link attached to a 12 GA red going back to the battery. I would assume Maxifuse here as well? This is the batt hot that feeds the body harness. I dewired my ammeter and tied the 2 leads together.
Click to expand...

If you have a 50 amp alternator , I would use a 60 amp MEGA fuse to protect .Your 8 gauge wiring will support a 60 amp circuit.

I am personally re-wiring a mopar project car and I am using a marine style sub-panel to protect the fuse panels (two), extra relays , and the feed into the ignition switch. A separate 175 amp mega fuse with 4 gauge wiring to the alternator ( It is a 165 amp alternator for Hemi engine) .I am also using relays everywhere I can to take the load off the ignition switch and Head light switch.

Every project is going to be different, I would take an amperage reading with everything running and see how many amps are going through the wire you want to protect.
You want the fuse to be a little higher than that , but not fusing more than the wire gauge can handle.
A pro-touring car with EFI, power windows, A/C , sound system, electrical fans, high output headlamps etc. is going to need a lot more than the factory ever needed.

It's like house wiring you run a 15 amp circuit breaker with 14 gauge wire , if you are going to run more amps in that circuit you will step up to 12 gauge and 20 amp breaker and so forth.

If you are pulling more amps than a 12 gauge wire can handle , then you need to feed the higher draw circuits with a separate relay to lower the amperage to an acceptable level.
 

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You could use one of these. 6 gauge wire and 60 amp capable. Easy to step from 8 to 6 for the short run of the fuse holder

I have a few of these and some 40, 50 or 60 amp maxi fuses.
 

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I have a 75amp alternator ...do they make a 85amp fuse and holder or what would u recommend ...they show I should use a 10 gauge wire from the alt. to battery. Also where would be the best place to put the fuse holder.
 
I used a fuse on the alternator output in both A's. It is in the fuse/relay box from a Jeep I installed. It is at least 60 A (forgot). Using a 12 awg as a fusible link seems kind of silly when in series w/ an 8 awg. Direct off the BATT+ feed, I put a large fuse (180 A?) that looks like post #9. I have an in-line Battery Brain, so was easy to bolt to its terminal. I wrapped all exposed copper w/ silicone tape. The starter wire comes direct off the battery and is unfused. I have seen some Jap cars that have high-amp fuses inside the BATT+ post connector, so even their starter is fused.
 
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