3g alternator with battery relocation question

DeathProof88

DeathProof88

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Dec 11, 2015
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#1
Hey guys, I've just installed the 3g alternator in my '88. The battery is in the trunk. The bracket is cut and the connectors are done. My only hang up here is trying to find an 8 gauge fusable link to connect to the alternator. I ran a 4 guage wire from the alternator area to the trunk. A 175 amp fuse is mounted to the battery box and then it will connect to the kill switch. The previous owner had a 6 gauge wire with two 12g (teal 3.5mm) fusable links connected to the alternator. I like the idea of having both ends protected as close as possible to the sources since power can flow from either end if the wire is cut. Should I double up on 10 or 12 gauge fusable links? I know there are inline fuse holders but they are bulky, I'll go this route only if I have to.
 

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#2
I don't think you'll find any fusible links under 10G. I think that's the heaviest gauge i've ever seen.

Technically two fusible links (or fuses) in parallel is not good wiring practice and should be avoided. In theory you would assume it would double the ampacity, but in practice it will result in unpredictable behavior.

175A is also too high of a fuse for 4G wire with battery in the trunk. Really you would want something more like 100A. While 4G wire is good for the 130A alt and battery in the engine bay, the increased distance of trunk mount will cause voltage drop and higher ampacity so really you want 2G or 1/0 wire for trunk mounted setups, especially if the wire is subpar quality.
 
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#3
Well that was expensive, I spent like 45 bucks on 4g thhn to upgrade the previous owners 6 gauge job. I'm sure it worked fine for him for years but I'll lose sleep over it haha. Re running a 2g will be a little work but I'll do it. Are you fusing both ends of your wire? I feel like it's necessary. And I liked the fusable link at the alternator connection do to the flexibility. Bending a 2g thhn is gonna be tough.
 
#4
I don’t have a trunk mount battery so my setup will differ

I used welding cable for my run with a single fuse on the alt wire. Really the fuse is for protection against reverse polarity battery hookups.

THHN is gonna be a pain to bend, which is why I use welding cable. However not sure the cost of 2g or 1/0 welding cable. Remember, THHN insulation won’t resist UV so if any is exposed to sun you’ll want to wrap it.
 
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#9
DeathProof88 said:
Welding cable insulation won't resist fuel and oil tho.
Click to expand...

EPDM insulation on welding cable is resistant. It’s on par with battery cable.

Marine battery cable is also an option as it has a much higher strand count.


Really you have a few options here and pros and coins to all. You’ll have to pick based on your planned routing and such.
 
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#12
Holy hell. If you can drag welding cable through the mud, rocks, and water on a pipeline job for weeks on end welding pipe, fittings, and flanges then it will hold up to a walk in the park like being on your car.

I have been running welding cable on my cars for over 20 years and never have a problem. Choose a path that is tight to the underside of the body and support it correctly with insulated clamps.
 
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#14
AeroCoupe said:
Holy hell. If you can drag welding cable through the mud, rocks, and water on a pipeline job for weeks on end welding pipe, fittings, and flanges then it will hold up to a walk in the park like being on your car.

I have been running welding cable on my cars for over 20 years and never have a problem. Choose a path that is tight to the underside of the body and support it correctly with insulated clamps.
Click to expand...
Are you a welder? I am, tomorrow follow your ground cable from end to end and tell me there's no holes or cuts in it lol. But sitting in a car is a different story, thanks for your input, I didn't consider that until you guys posted about it. The same argument could be had about me just leaving the previous owners 6 guage setup in the car. He had a 3g alternator and trunk mount battery for years with issue. I think a little too much so I'm going to replace the 4 guage thhn wire that I just ran in it with 2 guage and mount a 175 a maxi fuse on the pass fender and battery box. If I could buy epdm welding cable near by then I would use that. Thanks guys.
 
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#15
No sir but I’ve watched many a rig on site welding up pipeline and they seem to make some pretty welds from start to finish on hundreds of miles of pipe.

The strand count is outstanding and lug selection is great. I crimp the ends and then double heat shrink them. So the first piece of heat shrink is short and covers the gap between the lug and the wire insulation. Second piece is longer and completely covers both ends of the first piece.

Order my cable from here:


Order logs and heat shrink from here:

CrimpSupply.com | In Stock and Available to Ship Today

A crimpable connectors, tools, cable ties, packard metri pack, weather pack, terminals, truck lighting, shrink tubing and terminal company.
crimpsupply.com crimpsupply.com

I use a Deka hammer crimper and have made hundreds of crimps with it. The hydraulic crimpers (have one of those as well) make a prettier crimp but they are more expensive. You can probably find a comparable one cheaper but I can vouch for this one.

 
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