Big 3 Too Small?

[phatphuck]

Just decided to upgrade my engine bay wiring with the big 3 and also do starter and main fuse block power wire as well.

I went with a high quality 4ga. wire and a 250A ANL fuse for the alternator as I plan to upgrade that sometime soon too.

However, I'm looking around and starting to think I went too small with a 4ga.

FYI I do not plan to run a ton of accessories or high draw components in the truck just beef up oem power and grounds.

Whats the thoughts on this?

 

[TheAutumnWind]

That should be more than fine. I went completely overkill with 0 gauge just because.

Is your 4 ga 100% ofc? If so np. If its cca I'd throw it ou .

 

[TheAutumnWind]

What's your plan for the alt? I went with an ad244 (nbs alt). Pretty easy swap. Way way more hot idle amps. Available cheap at 145 to 160a versions. More than enough power.

 

[phatphuck]

That should be more than fine. I went completely overkill with 0 gauge just because.

Is your 4 ga 100% ofc? If so np. If its cca I'd throw it ou .

Ok. I thought surely 4ga would be enough. I mean the oem stuff is mostly 6-10 under the hood from what I can tell

What's your plan for the alt? I went with an ad244 (nbs alt). Pretty easy swap. Way way more hot idle amps. Available cheap at 145 to 160a versions. More than enough power.

Well, I have the vortec 7.4 BBC so not exactly sure what my options are honestly. But was thinking somewhere in the 200A range to cover anything I may need going forward. Mostly projector retrofits, a small amp and sub, additional lighting etc.

 

[RawbDidIt]

4ga is plenty for now. I too went overboard with 1/0ga for alternator to battery, negative to fender, and negative to alternator, but I'm running 1400W of sound and plan on running 2 10" light bars and corner lights in the future. I went 4ga to the fuse block because it's plenty, and it fit perfectly in the channel across the top of the radiator fan shroud. As stated, no copper clad aluminum, stranded solid copper or don't bother.

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[kennythewelder]

When I did mine, I went with #2 ga welding lead. I was going to use #4 ga welding lead. Through the years, the physical size of the wire has changed. The salesman at the welding supply said its because there are more strands of wire in the smaller OD of the new welding lead, compared to the old larger OD welding lead. So when I bought my connectors from a local custom truck shop, I asked them what they thought about my choice. The ask what size amp I had. I said a 680 watt. But I do have electric fans. They said that a #4 ga wire would be big enough, bit like I said, I went with a #2 ga. The only down side that I see, is that at night, with everything on ( including the AC) the volts at idle do drop to around 10. But as soon as I take off, I get 14 volts. I did the big 3 just before I did my fan swap. About IDK 1 1/2 years ago. So far, so good. Keep in mind, that doing a big 3 adds wire to the OE system, and doesnt remove any wire, so any upgrade in wire size over OE, will be an improvement. Also the truck shop, did say that all of there big 3 up grades are done with 0 ga wire, but most of the time it is to support a very large amp, or amps. One other thing, I also added 2 more grounds. So on my truck, I have a fused wire going from my alt, to the pos battery connection, a ground from my alt case to my neg battery, a ground from my bat to the frame, ground from bat to engine block, and bat ground to truck cab. After doing the up grade, my wipers speed up. Guess I needed to improve the cab ground after all.

 

[BNielsen]

Ok. I thought surely 4ga would be enough. I mean the oem stuff is mostly 6-10 under the hood from what I can tell



Well, I have the vortec 7.4 BBC so not exactly sure what my options are honestly. But was thinking somewhere in the 200A range to cover anything I may need going forward. Mostly projector retrofits, a small amp and sub, additional lighting etc.

@5vortec7 makes an incredible Big 3 kit, I'm excited to install mine; I think he used 0/1 gauge wire for most of the grounds and power.
You can do the AD244 on the 454, you'll need to change from the CS144 square plug to the CS130/AD244 oval plug. It would be wise to run a voltage sensing wire to the fuse/relay center so the alternator can read what voltage it needs to push.
You should be able to get by without it, the alternator should default to running 14.5 volts.

 

[phatphuck]

When I did mine, I went with #2 ga welding lead. I was going to use #4 ga welding lead. Through the years, the physical size of the wire has changed. The salesman at the welding supply said its because there are more strands of wire in the smaller OD of the new welding lead, compared to the old larger OD welding lead. So when I bought my connectors from a local custom trick shop, I asked them what the thought about my choice. The ask what size amp I had. I said a 680 watt. But I do have electric fans. They said that a #4 ga wire would be big enough, bit like I said, I went with a #2 ga. The only down side that I see, is that at night, with everything on ( including the AC) the volts at idle do drop to around 10. But as soon as I tale off, I get 14 volts. I did the big 3 just before I did my fan swap. About IDK 1 1/2 years ago. So far, so good. Keep in mind, that doing a big 3 adds wire to the OE system, and doesnt remove any wire, so any upgrade in wire size over OE, will be an improvement. Also the trick shop, did say that all of there big 3 up grades are done with 0 ga wire, but most of the time it os to support a very large amp, or amps. One other thing, I also added 2 more grounds. So on my truck, I have a fused wire going from my alt, to the pos battery connection, a ground from my alt case to my neg battery, a ground from my bat to the frame, ground from bat to engine block, and bat ground to truck cab. After doing the up grade, my wipers speed up. Guess I needed to improve the cab ground after all.

Where was your alt ground? Whats the extra benefit of adding it?

 

[RawbDidIt]

Where was your alt ground? Whats the extra benefit of adding it?

You can mount an alternator ground to the bottom bolt on the alternator mount easily. Same benefit as any other ground: provides a more direct route between negatively charged components of the electrical system.

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[5vortec7]

Here’s the kit I make...
View media item 32277
And here’s a link to my thread...
https://www.gmt400.com/threads/big-3-and-dual-battery-kits.41818/

let me know if you have any questions