Technical Rebel Wire Harness diagrams and wiring info

I have a charge wire kit from Vintage Auto Garage that came with 10ga wire and 125a inline fuse that I plan to use.

 

Do what you want. You asked if it would be safe. In my opinion, a 10 ga that long will be undersized and could overheat. Perhaps I am reading more length into your deal than is there. I use an 8ga on mine for a shorter run.

Ben

 

You could also run it down the left side of the engine and then around and down the back with the start wire and connect it to the stud with the battery cable. No need to run it way back to the battery. Size of the wire would be determined by the output of your alternator. Step up to 8 gauge if your alternator is 80 amp or greater. 10 gauge is good otherwise. Safer than running it in and out thru the fire wall and along with other parts of the harness. Shorter run of this wire would also be better.

 

Routing it this way will shorten total length to roughly 6 ft. Sounds like a good idea. What about location of the inline 125 amp fuse. Should it be close to one end of the wire or anywhere that’s easy to access?

 

All that fuse will do is protect that one wire, IF there is a short.
I consider it unnecessary.
But if you want to use it, I suggest it should be near the alternator.

 

Isn't that big fuse intended to go in the main battery feed to the fuse panel. Usually located close to where it is connected to the battery terminal on the starter solenoid or starter relay depending on the engine.

 

no the Rebel kit came with a fusible link for main feed. Charge wire kit came from vintage auto garage with a fuse.

 

Ok, so now I have read all kinds of recommendations from posts here, on other online sources like American Autowire and Google searches on what folks do and why. I am so confused on what to do for my charge wire other than I need to upgrade from 10 ga to 6 or 8 ga for my 90 amp alternator. The charge wire measures about 40” from alternator to bat post on firewall mounted solenoid.

Some folks don’t use any wire protection, some use fusible link, some use a fuse, some use circuit breaker and some use multiple fuses.

 

Think about what is involved and what COULD happen.
12 volt battery on one end. It has a lot of amps stored in it hopefully at all times.
Alternator that when engaged will provide a lot of amps. It can fail WOT and overwhelm the wiring but this is very rare.
The wiring between the two. It is sized to handle normal and peak loads.
So long as the system works as designed and is sized and installed properly, there should be no problems.
If the wiring is somehow shorted to ground, the battery will discharge enough to melt the wiring and fire.
If the engine is running and the alt spinning during this, it will melt the wiring and fire.
Best bet is to prevent shorting. Route the wire safely and protected.
The safety features will only work if they are between the short and the component providing power.
With engine off, the battery holds power. So protection should be at the battery.
With system charging, both ends have power. So protection should be at both ends.
But now you have introduced 2 new components and 4 more connection failure points.

 

Us an external charge wire as you are planning.

Upgrade to 8 ga to suit your alternator output, and put the fuse on the battery end.

If you are worried about an internal failure of your alternator add a fusible link on that end.

Most important part is make your wire crimps properly, mechanical connections tight and secure, and harness runs routed and anchored to prevent damage.

 

Wire sizing math and charts are easily available here and elsewhere. To my mind, I want to run a circuit once and have peace of mind that even after years of use, I don't have to inspect for issues.
This doesn't mean I'd run double ought for every circuit. However, the cost and weight penalties of running an 8 gauge versus 10 gauge is insignificant provided both are on hand. Research max output, wire length and figure out what is recommended.
Here's one from NAPA for auto use. Many online are for stationary, home or other uses.
https://knowhow.napaonline.com/automotive-wiring-guide/
Right near the top, it has 0-5 feet and going over to 80-100 amps it says 4 gauge. This is probably overkill, since the charging system is only max output under extreme situations for short periods. The chart does not mention constant rating, but considering the number which is much higher than others, it probably is.
However, since you are only making one harness (no big cost issue) and want it to never be a concern and you are running it near hot exhaust (affects circuit and insulation) why not?
Roadkill shows 6 gauge
https://m.roadkillcustoms.com/alternator-wire-gauge-chart/
Speedway says under 5 feet, 6 gauge. Over 5 feet, 4 gauge.
https://www.speedwaymotors.com/the-...0107?msockid=03c14b7ae4cf6470288f5d30e56765e3

However, this site has a couple links down the page.
https://www.autorewire.com/
The chart shows 100 amps as a 12 gauge wire,
https://www.autorewire.com/image/amps-wire-gauge-size-chart_436020.jpg
That seems very small compared to other recommendations!
but the basic rod circuit shows a 10 gauge wire in the generator output circuit.
https://3.bp.blogspot.com/_-z9Chr5k...AAAG0/9HuW_Dh2EwM/s1600/BasicHotRodWiring.jpg
The GM alt link is dead, but many others mention a 10 gauge output wire.

So I understand the confusion. But it's your car, your choice. I'd go overkill.

 

thank you for all the links. Browsed them all. I am going with 6 ga wire and the 125a fuse.