Big 3 Upgrade + 250AMP HO Alternator

BoldAdventure

Original poster
Member
Jun 28, 2012
1,634
NOTE: I am not an electrical engineer, so don't take my information as such. I know a number of you are far more knowledgeable in this area than myself. This is just a write up on what I did, and not meant to be an explicit guide. I know that there are some videos on this. I posted this on ORTB, and thought I'd re-share here.

BACKGROUND:

I know alot of us members have quite a few electrical components running off factory wiring and our factory alternator. Hid's, Amps, Winches, Aftermarket HU's, Off Road Lights, Power inverters, Refrigerators, CB's, Ham Radios, Laptops, etc. Our vehicle’s stock electrical systems were designed for such---stock electrical. When you start adding things like audio equipment (amplifiers), aftermarket lights, etc, you are increasing the demand put on your electrical system.

Most of the time stock wiring is right around 8 awg (give or take). It’s simply not designed for the extra current draw required by aftermarket items. Let’s use a garden hose as an analogy to electrical wiring. If you have a long, thin garden hose, the flow of water through it will be much less than a short, thick hose. Compare a 100-ft, 5/8” diameter garden hose to a 1-ft long, 6” diameter section of water supply PVC pipe. The flow will be much greater through the shorter, thicker section (less pressure). The same goes for electrical systems. The larger and shorter your wiring, the less resistance to the flow of current.

Even if you do not have any issues with voltage drops, dimming headlights, or anything like that, the Big 3 is still highly recommended. Stock electrical systems can benefit from the Big 3. It’s probably the cheapest upgrade one can do for their electrical system. While it’s generally recommended to use 4 awg or larger wiring for upgrading the Big 3, I highly recommend using 1/0 from the start. It’s the best option and only costs slightly more. Better to do it right the first time around.

Also note; no conductor is 100% efficient, but larger AWG wire helps to overcome resistance and transfer greater amounts of amperes throughout the system with smaller losses in energy. This is why people generally do the "big 3". It's pretty common for audio guys with massive 1000 watt stereo systems do this sort of thing.

One more thing; I know this is a readily talked about topic, but your alternators primary purpose is not to charge your battery. It is made specifically to run all your electrical components such that your battery doesn't need to. Sure, your alternator charges the battery when current is available, but that is not its primary purpose. This is why when your alt. dies, your battery can only run the entire system for a very short time (its not a deep cell). The batteries main purpose is to help regulate spikes in voltage coming from the alt, and to crank the truck. And only when your alt. can't supply the system does your battery get used.

The factory Alternator is a 150 amp unit that is connected to the battery with a 6 gauge wire. I decided to replace mine with a 250 amp alternator and run 1/0 awg gauge wire to the battery.

alt_old_vs_new.jpg



WHAT IS THE "BIG 3" UPGRADE?

When someone refers to the Big 3 they are referring to upgrading the three main electrical wires in the vehicle’s system:
1. Battery (+) to alternator power wire
2. Battery (-) to ground (frame)
3. Engine block to ground (frame)

On our GMT360's there is actually a third ground which is Battery (-) to the fender. I also upgraded this ground just cause I was there doing it.


DOING THE "BIG 3" UPGRADE

Note: The following is the method I used and the materials I used. If you have a different tool or method feel free to use it---as long as it gets the job done safely.

copper_choice.jpg


I highly recommend welding cable for this! It is super flexible and you do not need any plastic covers. It is highly durable and over 99% copper. Please be aware any wire containing ALUMINUM is not a good choice. Although the aluminum clad wire is cheaper, it does not conduct nearly as good as copper. So choose your materials appropriately. I paid a lil premium for some fancier stuff in fun colors.

**I used 8ft of flexible 1/0 gauge high-strand wire and 8ft of 4 gauge high-strand wire. Now, I use this much because I bought blue and red wire. If you wanted, you could just get one color and you'd only actually need 5ft of each.

First thing I did was remove the factory wiring and determine what I was going to replace by examining the way the factory wiring is connected.

oem_postive.jpg


oem_negative.jpg


I decided against currently replacing the wire to the starter, just because I didn't have a terminal appropriate for it.

Some might wonder about this decision, but I decided to run 1/0 gauge wire from the alternator to the positive side of the battery and 1/0 gauge wire for the negative side of the battery as the main ground to frame.

For my battery terminals on the 1/0 gauge wire I used copper connectors rather than ring terminals.

wiring_job.jpg


Which btw, if you do not have a crimper a big hammer and a chisel work just as well. If you want extra peace of mind, I cut up solder and insert it into the bottom, then place the wire in, and hit it with the acetylene torch, this solders the connection. Then I crimp it, hit it with the torch again and heat shrink it. That won't come apart.

manual_crimp.jpg


neg_wiring.jpg


After crimping all my wires, I made sure to hook my main positive lead to the back of my alternator and installed the alternator.

new_alt_installed.jpg


After getting the alternator installed I ran all the ground wires to the factory locations. I made sure to clean and prep the surface with a wire brush and sandpaper for good ground contact. First up was the Battery Neg (-) to the frame, which is 1/0 gauge wire.

grounded.jpg


From the frame ground I ran 4 gauge wire to the engine block ground.
engineblockground.jpg


After that I connected the negative cables to the battery and proceeded to connect the positive to the battery. It's hard to see, but I also replace the battery positive wire to the main fuse block with 4 gauge wire.
post_to_alt.jpg


That's about it. :thumleft:

Aside: BTW, if you want my opinion, a nice AGM style battery goes along with this setup well. I just recently replaced my old one with this K-Mart unit:

new_battery.jpg
 

kickass audio

Member
Aug 25, 2012
955
NICE choice in wire, SHCA is top notch. I have a lot of tsunami, rockford fosgate and knukonceptz wire in my truck, all 1/0. The SHCA 1/0 is more like 2/0 wire. Very under rated wire gauge and high quality.

What brand alternator do you have? That pulley is poor for a high output alt like that tbh. The larger the pulley the worse output you get at low rpm's so you are straining the alt at idle and low speed. I have a tiny pulley on mine and have a Mechman 270a alternator on mine.

Nevermind the black belt residue on the alt casing, I was using the junk belts from autozone that slip real bad and went to a gates belt and have had 0 slipping.

View attachment 32484

I kept the factory wiring in the truck but added my big-3 wires up on top of it. I used the bolt that attaches the mount for the engine just above the alternator as my engine ground, I drilled a hole on the under side of my frame rail below the battery to use as my frame ground and went straight to the alt for my alt upgrade. What's the output stud look like on your alt? Tbh, not trying to talk smack or anything but most companies out there keep the tiny little stud the factory alt has but upgrade the diodes and they always burn out.

edit: aren't you the guy who trolled me and said you run wet cell in your truck instead of the AGM in another thread? :hissyfit: hahaha.
 

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BoldAdventure

Original poster
Member
Jun 28, 2012
1,634
It's not SHCA wire. I just bought some of their connectors, which came with heat shrink.

The alternator is from here: http://www.dbelectrical.com/p-9753-...50-amp-42l-trailblazer-02-03-04-05-envoy.aspx

Thanks for your input.

I don't run any stereo equipment. This is phase 0 right now for me. I plan on adding a second battery shortly, and then I am probably going to adjust some of this to be a little more solid.
 
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kickass audio

Member
Aug 25, 2012
955
I know I didn't read the whole thing. :tongue: You should have plenty of electrical right now to back it up unless you have a light bar or winch or something you should have a really good electrical setup the way it is now. How much fun was it to get that alt out of there? Mine was a real pain for the bottom bolt with that AC line right in the way.
 
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Daniel644

Member
Feb 27, 2015
563
I'm confused, why did you drop to 4 gauge on those 2 other grounds, why not just keep the 1/0 going all the way thru the system? also, did you happen to note the lengths of the individual runs?
 

dmanns67

Member
Apr 3, 2013
32,979
Ohio
Daniel644 said:
I'm confused, why did you drop to 4 gauge on those 2 other grounds, why not just keep the 1/0 going all the way thru the system? also, did you happen to note the lengths of the individual runs?
I doubt you get an answer, he is not very active on here. Last I heard he was parting out his TB and/or sold it. Try shooting him a PM.

May03LT has a badass audio setup. He might be able to answer some of your questions. Only in a thread though, so that everyone can benefit from his knowledge :yes:
 
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Daniel644

Member
Feb 27, 2015
563
dmanns67 said:
I doubt you get an answer, he is not very active on here. Last I heard he was parting out his TB and/or sold it. Try shooting him a PM.

May03LT has a badass audio setup. He might be able to answer some of your questions. Only in a thread though, so that everyone can benefit from his knowledge :yes:
Well anyone is open to answering either question not just the OP, it just seamed like this thread was the place to ask so as to keep all of this type of info together in one place instead of starting a new thread thats related, since this is the first result when you search "big 3 upgrade site:gmtnation.com" on google.
 

Mounce

Member
Mar 29, 2014
13,667
Tuscaloosa, AL
Well, you were directly asking the OP questions about why he dropped to 4 gauge though and no one else will know his exact reason but him.. And no one put down your post so there's no reason to defend your reasoning.

Like Dmanns said, pm him and he might answer, I can't remember the last time he posted up so it's been a while. And in the meantime, if you need help, start a thread.
 
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x0duke0x

Member
Feb 17, 2014
108
Daniel644 said:
I'm confused, why did you drop to 4 gauge on those 2 other grounds, why not just keep the 1/0 going all the way thru the system? also, did you happen to note the lengths of the individual runs?
It shouldnt be too long, I think the 4guage wire was ran was due to the load not being that demanding for those two runs. So cost savings would have been in order. If you need a more technical answer, I wouls say puah 1/0 all the way around. For me I would do 1/0 all the way around, but I am going to try out PCM of NC wire lot first. Just to give everyone a good thread. Right not my 2 JL amps are killing my alternator. I Mean my sub makes my battery needle dance it's insane. I Of course bought a new alternator 250amp ho. But I'll save that for another day.
 

Daniel644

Member
Feb 27, 2015
563
Mounce said:
Well, you were directly asking the OP questions about why he dropped to 4 gauge though and no one else will know his exact reason but him.. And no one put down your post so there's no reason to defend your reasoning.

Like Dmanns said, pm him and he might answer, I can't remember the last time he posted up so it's been a while. And in the meantime, if you need help, start a thread.
PM sent, if the info is accurate it looks like he was logged in as recently as last week.

x0duke0x said:
It shouldnt be too long, I think the 4guage wire was ran was due to the load not being that demanding for those two runs. So cost savings would have been in order. If you need a more technical answer, I wouls say puah 1/0 all the way around. For me I would do 1/0 all the way around, but I am going to try out PCM of NC wire lot first. Just to give everyone a good thread. Right not my 2 JL amps are killing my alternator. I Mean my sub makes my battery needle dance it's insane. I Of course bought a new alternator 250amp ho. But I'll save that for another day.
I was looking thru some stuff and noticed I still had about 5 feet of my 1/0 welding wire left over, was just trying to get an idea on the lengths from anyone else who may have done this before, if there was some good reason for the 4 gauge I have plenty of scrap pieces (several feet or more in length) that I could use so as to save the cost of buying more wire, just need to get more ring terminals.
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
Considering this is a zombie thread...
Daniel644 said:
Well anyone is open to answering either question not just the OP, it just seamed like this thread was the place to ask so as to keep all of this type of info together in one place instead of starting a new thread thats related, since this is the first result when you search "big 3 upgrade site:gmtnation.com" on google.
The OP recently sold his TB due a change of plans in life... For a good thing

Daniel644 said:
PM sent, if the info is accurate it looks like he was logged in as recently as last week.


I was looking thru some stuff and noticed I still had about 5 feet of my 1/0 welding wire left over, was just trying to get an idea on the lengths from anyone else who may have done this before, if there was some good reason for the 4 gauge I have plenty of scrap pieces (several feet or more in length) that I could use so as to save the cost of buying more wire, just need to get more ring terminals.
You may get an answer and you may not since he has not been active here for quite some time. He checks in every now and then but He is on the road living a dream and may not get on very often. He frequents another forum more than he does here.
 
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Daniel644

Member
Feb 27, 2015
563
djthumper said:
Considering this is a zombie thread...
The OP recently sold his TB due a change of plans in life... For a good thing

You may get an answer and you may not since he has not been active here for quite some time. He checks in every now and then but He is on the road living a dream and may not get on very often. He frequents another forum more than he does here.
Understood, If I get a reply I get one if not I'll figure it out (atleast the lengths anyway) when the weather clears up and I can add that info here so if someone else searches on the subject like I did they can find it here (unless there is a better write-up I have missed in my searches). I've just always assumed it's better to bump an old thread then to start a new one discussing the exact same thing, at least thats what other forums I'm on prefer you do, was I wrong to do it this way?
 

Mounce

Member
Mar 29, 2014
13,667
Tuscaloosa, AL
Again, no one said anything negative about your post so there's no reason to be defending yourself about bumping an old thread....
 

x0duke0x

Member
Feb 17, 2014
108
So I want to grab a alternator, does anyone have anything to say about the DB Electrical? Here are the specs:
600RPM @ 125 AMPS
1200RPM @ 250AMPs
ASIN: B008R2DVMM

I was looking at this guy, it's a pretty nice price, or do I go with the Mechman Alternator G-8497250?
Mechman is around $350+
DB Electrical is around $220..
I know with this price I should just go with the Mechman, but I wanted some reviews. Thanks!
 

Daniel644

Member
Feb 27, 2015
563
x0duke0x said:
So I want to grab a alternator, does anyone have anything to say about the DB Electrical? Here are the specs:
600RPM @ 125 AMPS
1200RPM @ 250AMPs
ASIN: B008R2DVMM

I was looking at this guy, it's a pretty nice price, or do I go with the Mechman Alternator G-8497250?
Mechman is around $350+
DB Electrical is around $220..
I know with this price I should just go with the Mechman, but I wanted some reviews. Thanks!
I wish I could find a spec on the Mechman at idle to show you where the bug difference (other then build quality) is at, the thing I've noticed about ALL DB electrical alts regardless of application is there idle output is HALF of there max and the sad truth is that number is not much above a stock 145 amp units idle output of about 100 amps, what it boils down to is that alt likely wouldn't solve any voltage drop issues you get when your stuck at a red light or parked in a parking lot.
 

mrrsm

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Oct 22, 2015
7,598
Tampa Bay Area
This is a Decent Thread Resurrection worth mentioning because of what Jimmy from "1Road" covered in this linked Video around Six Years Ago (and so, it was fairly contemporary with the OP's Thread) explaining WHY "The Copper Wire Coin of The Realm" in Automotive Use can be found by making Ground and Bonding Wires-Straps out of #2 Gauge (THICK) Fine Strand Copper Welding Wire.

The Secret of course is hidden under the insulation as cabling made up from MANY Finer Strands of Copper Wire which lowers the Resistance of the Electron Flow in the bundle and provides Much Better Flexibility than simply getting a REALLY THICK SOLID COPPER length of Wiring which can be Too Stiff and thus, Work Harden sooner and Break Apart over time from the normal Gyrations of Engine and Body Roll Motions inducing Cable Flexing:

 

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