145amp alternator to starter wire gauge?

[beaterku]

Quick question. I was laying out the routing of my truck and engine harness last night and a question popped in to my head. Currently, I have an AAW harness on my truck. With the 350, it had a 10ga wire that ran from the alternator lug to the starter. I was going to use this same setup and then I started questioning the gauge of this wire. I think 10 ga is too small for the 145 amp alternator. What is everyone running? I'd like to keep this wire on the starter lug to keep wires off of the batter. It could be done in a relatively short run under the throttle body and down to the frame rail and over to the starter. Maybe 5' total. I was thinking 8 ga. Thoughts?

EDIT: I did some more digging and Painless offers this kit rated for 190amp: https://www.summitracing.com/parts/prf-30700

Maybe something like that is the ticket.

I'm also going to contact AAW and get their input. Edit again, AAW recommends 6ga for the 145. Sounds like I’ve answered my own question haha

[sprint_9]

I used 6 gauge on mine as well. Make sure you size your fuseable link or fuse appropriately.

If your in the market for top quality components check out https://ceautoelectricsupply.com/ I have been super happy with everything Ive bought, really nice wire.

[davepl]

Depends on the run length. To be right, to carry 150 actual amps at 14V, you need more like 2 gauge or ideally 0.

It doesn't matter if you don't need 145A and never ask the alternator to put ou 145A, but if you get it producing over 100A, you'll want at LEAST gauge 4, then 2 at 125, and 0 at 150.

And that's for fairly short runs! Mine is about 4', but if you're is short, maybe thinner is OK?

[Dead Parrot]

Better to have too large a wire and wonder if you could have used a smaller one then have one too small and be explaining to your insurance company that your truck is a burned out hunk of scrap.

For a guide, check what Chevy used on newer trucks where 140A alts are standard.

[SunSoaked]

I recently put a bad**s 150 amp high-end alternator on my 85. Replaced much of the underhood wiring and used a remote starter solenoid. Initially, I had a 2 guage wire. Then I realized I had no protection on the alternator. Did some research and ended up changing it to 6 guage and installed a maxifuse at the alternator. Currently running a 60 amp fuse with spares in the glovebox. That got me thinking...when will I ever pull 100+ amps? Never. If I add up the load of every single electrical component on my truck, it might add up to 30-40 amps.

[rpmerf]

A couple thoughts...

On the stock setup, where the alternator / generator & regulator tie into the 2nd junction, the cab and the battery are on parallel circuits. The alternator will feed all the electronics in the cab without having to go through the battery. The only current going to the battery is what is needed to maintain it. It sounds like with the setup you describe it will go alternator -> starter -> battery -> junction to cab.

I agree that you will likely never see more than ~30 amp load unless you have a *****in stereo, fuel injection, high wattage lights, electric fans, etc. The wiring on my truck is mostly stock. I have a 90 amp, with 8 gauge between the junctions and to the alternator. I have a 30 amp fuse between the battery and first junction. Only time it popped was when my voltage regulator went bad.

Always use a fuse for the size wire you have.

I believe my 97 Suburban comes from the factory with the 145 amp alternator. I wonder what size wire it uses, what length, where it is tied in to.

[beaterku]

Thanks everyone. I talked to American Autowire and a buddy who works for Painless and they both said 6ga with a 200amp Maxi fuse. I went ahead and ordered a kit.

In my truck, the way AAW sets it up, the starter post is the juntion point. The alternator connects to the start with a fuseable link. The lead coming from the bulkhead/fuse panel connects to the starter with a fuseable link. The battery connects to the starter. I'm just going to remove the AAW 10ga wire going from the alternator and replace it with a 6ga and a fuse.

I went out and checked out my dad's 2013 Tahoe and it has a wire that is at least 6ga with a 175amp fuse. The wire has no markings so I can't confirm accurate gauge.

[1971Stepside]

This thread got me thinking about my set up since beaterku and I are about the same spots on the motor.

I just set the stock battery cable/alternator wire set up back on the motor but it clearly wont' reach the battery on the other side of the radiator support. Please explain to me the best way to wire the battery and the alternator.

Do I just run the wire like beaterku is running from the alt to the starter and then the pos battery to the starter. Neg goes to frame? Do I need anything else? Thanks and sorry to hijack...

[beaterku]

Originally Posted by 1971Stepside

This thread got me thinking about my set up since beaterku and I are about the same spots on the motor.

I just set the stock battery cable/alternator wire set up back on the motor but it clearly wont' reach the battery on the other side of the radiator support. Please explain to me the best way to wire the battery and the alternator.

Do I just run the wire like beaterku is running from the alt to the starter and then the pos battery to the starter. Neg goes to frame? Do I need anything else? Thanks and sorry to hijack...

I don't think there is one correct way to do it. I am only using the starter as the junction because that is the way AAW set up their harness. I see no problem using the battery as the junction point. In fact, the 6ga alt wiring kit AAW sells says you can use either the starter or the battery. I like the start for ease of hiding the wires.

[sprint_9]

Originally Posted by 1971Stepside

Do I just run the wire like beaterku is running from the alt to the starter and then the pos battery to the starter. Neg goes to frame? Do I need anything else? Thanks and sorry to hijack...

For the most part I did mine like this as well. I ran from the battery to the starter, from there it branches off to the engine harness, chassis harness, and alternator.

When you say "Neg goes to the frame" are you referring to the battery negative? The battery should ground to the engine block, then to the frame and body/cab.

[1971Stepside]

Yes, I was referring to the battery negative. I've seen it grounded to the frame or the engine block. I can go to engine block...just need to find a spot to that. Thanks!

[mongocanfly]

I've seen the grounds from battery in both places ...frame and engine....with the LS everything needs to be grounded to death anyway so I dont think it's a big deal where you go with it....but I prefer mine battery to engine....that's the way the factory did it...mine came on the driver's side below the manifold on the block...I usually do mine to the head...