Why do you need the BIG 3 on stock electrical?

[Roland 10+ year member]

You seem to think that a car doesnt use any of the energy created by the alt using normal functions. Considering stock alts are under powered in 70% of applications, its safe to assume if you put an aftermarket audio system in that draws 50-60amps like you say, then you are already way above what your alt can handle and thus your big 3 is under sized as well.

No not at all. The few cars and vans i have measured only pulled 20-25 amps running without lights... the other 25-35 amps is for your audio system at normal listening volumes YMMV (just speaking in general : )

 

[whitedragon551 5,000+ posts]

No not at all. The few cars and vans i have measured only pulled 20-25 amps running without lights... the other 25-35 amps is for your audio system at normal listening volumes YMMV (just speaking in general : )

God forbid you need AC, heat, your cooling fan kicks in, you open the sunroof, or need windshield wipers.

 

[big scott]

in the case of my s10 blazer.

when i got it it came with a 79amp alt.

all was stock. when i turned on my heater, wipers and had my lights on i had bad voltage drop.

i hat to turn off something and it was noramly my wipers.

well i replaced my stock grounds ( body to engine- body to frame ) it got a lot better.

so i replaced my alt wire with some 8ga and did 8ga from battery to starter.

that cured my voltage drop.

it just shows that stock wires on a stock truck are not the best.

so just putting same size or 1 size bigger i eliminated my voltage drop.

i could have all my stuff on at a red light and did not worry about the truck stalling.

so even on a stock car you can make it better by using even 1 size bigger.

and now that i have all this stiff i have used all 1/0 on everything, including my starter.

he just would not listen. and its ashame . i was never that bad when i was 17 .

i was blueprinting engines at 17.. i listened to others .

 

[Boomin_tahoe 5,000+ posts]

in the case of my s10 blazer.when i got it it came with a 79amp alt.

all was stock. when i turned on my heater, wipers and had my lights on i had bad voltage drop.

i hat to turn off something and it was noramly my wipers.

well i replaced my stock grounds ( body to engine- body to frame ) it got a lot better.

so i replaced my alt wire with some 8ga and did 8ga from battery to starter.

that cured my voltage drop.

it just shows that stock wires on a stock truck are not the best.

so just putting same size or 1 size bigger i eliminated my voltage drop.

i could have all my stuff on at a red light and did not worry about the truck stalling.

so even on a stock car you can make it better by using even 1 size bigger.

and now that i have all this stiff i have used all 1/0 on everything, including my starter.

he just would not listen. and its ashame . i was never that bad when i was 17 .

i was blueprinting engines at 17.. i listened to others .

When I had my s10 blazer, I got a Ea alt, did the big 3, 2 gauge wiring, and Optima battery. Was plenty of upgraded electrical and I didn't even run much for a stereo system but always better for overkill than not enough. I didn't wanna have to worry about going back to change something. I'm a do it right the 1st time type of guy.

 

[Roland 10+ year member]

God forbid you need AC, heat, your cooling fan kicks in, you open the sunroof, or need windshield wipers.

I've measured my vans electrical with everything ruining and audio at max volume... but I'm not sure what your point is.

We were ONLY talking about the alternator to battery power cable. It doesn't matter even if the demand was over the alternator's it's rated power, the alternator will only put out what it can, in the OP's example 100 amps. Like pointed out already, upgrading that one cable from 8ga to 4 ga can only give you an extra 0.22 volts maximum on a 5 foot cable. Not really a big deal in this example.

 

[The_Quiet_One 10+ year member]

I've measured my vans electrical with everything ruining and audio at max volume... but I'm not sure what your point is. We were ONLY talking about the alternator to battery power cable. It doesn't matter even if the demand was over the alternator's it's rated power, the alternator will only put out what it can, in the OP's example 100 amps. Like pointed out already, upgrading that one cable from 8ga to 4 ga can only give you an extra 0.22 volts maximum on a 5 foot cable. Not really a big deal in this example.

What temp are you getting that .22 max voltage gain? You have to be careful throwing out hard numbers like that. There's several variables that play into what voltage drop you actually see ie temp, wire characteristics, the other components of the charging system etc.... A car's electrical system is not a static system in laboratory settings. You can't easily quantify how the system will react in a daily, dynamic environment.

 

[Roland 10+ year member]

What temp are you getting that .22 max voltage gain? A car's electrical system is not a static system in laboratory settings. You can't easily quantify how the system will react in a daily, dynamic environment.

(Quote)

"would some actual numbers have helped?

100A through 5' 8 ga = .315v drop

100A through 5' 8 ga stacked with 4 awg = appx .085v" (Unquote)

.315 -.085 =.23v

I doesn't matter that the system is dynamic This is the maximum voltage gain you can gain because your system Can't pull more than 100amps. Your gain from that upgrade will be much less than 0.23v because you will be pulling dynamic power between 50 - 100 amps but never more.

 

[The_Quiet_One 10+ year member]

No. I disagree. The smaller wire can heat up more quickly under heavy load and increase resistance and therefore voltage difference between gauges. What's the amount of heat dissipated in 4 GA with 100 amps and 8 GA with 100 amps. Voltage drop across wire isn't a static number across every scenario.

Oh well the information from several different opinions is here for any future readers. Let them make up their mind. Regardless I think the conclusion should be unless you're broke as hell it can only help to do the big 3, although the extent of that gain will vary. Next fun thread should be "Does doubling power or cone area result in an increase of 3 dBs"

 

[Roland 10+ year member]

No. I disagree. Not sure were we disagree but that's ok

The smaller wire can heat up more quickly under heavy load and increase resistance and therefore voltage difference between gauges.

Agreed

What's the amount of heat dissipated in 4 GA with 100 amps and 8 GA with 100 amps.

The 8 will put out more heat and have more resistance

Voltage drop across wire isn't a static number across every scenario.

Agreed, but when the power is static the voltage drop is static also. So we look at what is the highest power a wire can possible see and we can do the math and determine the wires maximum voltage drop which were the numbers i quoted came from

Oh well the information from several different opinions is here for any future readers. Let them make up their mind. Regardless I think the conclusion should be unless you're broke as hell it can only help to do the big 3, although the extent of that gain will vary. Next fun thread should be "Does doubling power or cone area result in an increase of 3 dBs"

Yep cone area sounds good, i think this horse is dead. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Edit, The battery handles all (Dynamic) power demands above the alternator's max output, so larger gauge wire form the battery gives the real benefits to the amp.

 

[tymoto21 10+ year member]

For ops reference in my car I gained .2v (at amp terminals) charging at idle by running 2+,2- 1/0 runs to my amp. And sustained .4v gain while under load.

Drawing around 2kw from a 90a alt and one old battery I stayed .4v higher by adding a couple wires.

Just to clarify that is the difference between dropping to 11.7v or 12.1v

I would much rather have the 12.1

And this was my real world experience

 

[-unknown-]

I would like to apologize to anybody I offended or insulted. Thank you all for helping me, I hope you accept my apology. I would like to add I learned a lot in a very short amount of time reading on the12volt and bcae1. Although I do agree with roland on this subject, it was still very immature of me to act the way I did. With that said, I will let this thread and all of our differences subside.

 

[xr650jkallen]

I don't know all the technical formulas off the top of my head. What I do know is that when I upgraded the stock alternator wire that was maybe a heavy 10ga fusible link to a 2ga welding cable everything on my truck seemed smoother. The transmission shifter smoother, the windows were faster and I'm pretty sure it wasn't placebo effect. People that ride with me that didn't know that I had done anything, we're making comment about how much smoother it was. I figure anything that can make the alternators job easier can't hurt anything.

 

[evilmonstertruk Premium Member]

The big 3 def made a difference. But it wasn't till I got my AGM that I noticed the biggest difference.

Sent from my Nexus 6 using Tapatalk

 

[hispls 5,000+ posts]

Late to the party here, but I believe that car manufacturers use the absolute bare minimum they can get away with when choosing what size wire to use.

Assuming you're paying 15$ for shipping and at least 1.20 per foot of #8 wire, what's the difference in cost to overkill and use #1 /0? 15$? All in, you're looking at under 50$ to just do it in all OFC and be done with it. This is an upgrade you can remove and use for every vehicle you ever own.

I can say from experience that you can get away with doing a lot on stock electrical system, but why half arse things and risk poor performance or even electrical fire from exceeding ampacity of your stock cable?

 

[big scott]

Late to the party here, but I believe that car manufacturers use the absolute bare minimum they can get away with when choosing what size wire to use.
Assuming you're paying 15$ for shipping and at least 1.20 per foot of #8 wire, what's the difference in cost to overkill and use #1 /0? 15$? All in, you're looking at under 50$ to just do it in all OFC and be done with it. This is an upgrade you can remove and use for every vehicle you ever own.

I can say from experience that you can get away with doing a lot on stock electrical system, but why half arse things and risk poor performance or even electrical fire from exceeding ampacity of your stock cable?

agree 100%

why risk it.