What is exactly the big three

 

Bronze Member
Username: Saoxcore

Post Number: 42
Registered: Jul-06
and how does it help your car/system?
 

Gold Member
Username: Ctmike

Ct.

Post Number: 1219
Registered: Feb-06
from sounddomain.com forum:

As many of you know, upgrading the "Big 3" wires in your engine compartment can lower the overall resistance of your entire electrical system. The effects of the lower resistance are typically:

1) Reduced dimming and smaller voltage drops
2) More stable voltage and better current flow
3) Less strain on your vehicle's charging system

So for those of you looking for a cheap and easy way to upgrade your system and help out your electrical system without adding a high output alternator or an aftermarket battery, this is the modification for you. If you have heavy dimming or are getting large voltage drops during loud bass hits, but you don't have the money to spend on a high output alternator or a battery, upgrading your vehicle's "Big 3" will usually help to reduce and sometimes even eliminate the problems. So without further ado, the "Big 3" wires are:

1) Battery negative to chassis
2) Alternator to battery positive
3) Chassis to engine

Now, I suppose it would help if I explained what each of these wires does, and to do that I would like to paraphrase an explanation by IMTfox from a while ago: Think of your vehicle's charging system as two different circuits, one consisting of your amplifier and your battery, and the other consisting of your alternator and your battery. The current in your electrical system flows from your positive battery terminal to your amp, from your amp's ground to the chassis, and then from the chassis back to the negative battery terminal. But how does it get to the positive terminal in the first place? That's where the alternator comes in. Current in the second circuit flows from your alternator's positive post to the battery's positive terminal, then from the battery's negative terminal to the chassis, and from the chassis back to the block, which happens to be the grounding point for your alternator.

So, from your battery, you have the power wire going to the power terminal on your amplifier and then your amplifier is grounded to the chassis of the vehicle. From here the current needs a way to get back to the negative battery terminal, and that way is through the first of the "Big 3," the battery negative to chassis wire. Upgrading this wire will "upgrade" the circuit between your battery and your amp by giving the current a larger path to flow through to get back to the battery.

Now, think of your alternator as the battery and your battery as the amp. From the positive post on your alternator, you have the second of the "Big 3," the alternator to battery positive wire supplying "power" to your battery. From there the battery, just like your amp, is grounded to the chassis through the wire mentioned in the previous paragraph. Again, the current needs a way to get from the chassis back to the alternator's "negative terminal" and that way is through the last of the "Big 3," the chassis to engine wire. Since your alternator is most likely mounted to your engine block using a metal or conductive mounting bracket, you can simply add your new wire from the chassis to one of the mounting posts for the alternator. Upgrading these two wires will "upgrade" the circuit between your alternator and your battery, again giving the current a larger path to flow through.
 

Gold Member
Username: Illuminator

USA

Post Number: 3830
Registered: Apr-05
Some things need to be corrected in that post...I wish it wasn't so popular:

1) Reduced dimming and smaller voltage drops

Mostly if the existing wiring is too small, which isn't always the case.

2) More stable voltage and better current flow

More stable voltage is the same thing as smaller voltage drops as mentioned in #1, in addition, more current flow doesn't mean there will be more current available from the alternator.

3) Less strain on your vehicle's charging system

Again, only if the existing wiring is too small.

The 'big three' can easily take 1-2 hours and really isn't worth it unless you have obtained a HO alt of which it's practically necessary if you want to take advantage of the new HO alt (and not melt wiring).


quote:

The current in your electrical system flows from your positive battery terminal to your amp, from your amp's ground to the chassis, and then from the chassis back to the negative battery terminal.




ONLY if you are running your amp with the car off, if the car is on, it flows from your positive output on the alternator to the positive battery terminal (if that's where you have your amp wired) to the amp to the chassis to the engine block. Ultimately, your amp isn't wired to the battery, it's wired to the alternator. You could wire your amps and everything up directly to the alternator, the battery just happens to be more convenient. The battery is in circuit to be recharged is all, otherwise it wouldn't even be there(except to start the car certainly). It's a 'bonus' that the battery can provide power when the alt can't, but then you're killing your alt slowly if that's the case.
 

Bronze Member
Username: Saoxcore

Post Number: 43
Registered: Jul-06
hm.. how much money would it cost to do the big three?
 

Gold Member
Username: Illuminator

USA

Post Number: 3834
Registered: Apr-05
Not too much, actually. Probably 20-30min including 4ga wire and connectors. Make sure you have a method of securing the 4ga wire to the appropriate connectors.
 

Gold Member
Username: Ctmike

Ct.

Post Number: 1228
Registered: Feb-06
all you need is the cost of the wiring, you can shop around for some 0 gauge at stores that sell it by the foot. i know elemental designs have a big 3 wire kit for like $50. and if you can't do it yourself have someone else do it for free or get it done at a audio shop, they shouldn't charge to much.
 

Bronze Member
Username: Saoxcore

Post Number: 44
Registered: Jul-06
hm, okay. im just worried that after i put an alpine type r, and an alpine mrd m605, my car wont be able to handle it.
 

Gold Member
Username: Ctmike

Ct.

Post Number: 1229
Registered: Feb-06
just one m605? your car will handle it fine, unless your alt. is like 30a or so.
 

Bronze Member
Username: Saoxcore

Post Number: 47
Registered: Jul-06
okay, good. i just dont really know how good my engine is and stuff, and how much itll handle.
 

Gold Member
Username: Illuminator

USA

Post Number: 3837
Registered: Apr-05
Yeah, your car's charging system will have no problems with that amp. No reason to do the big three in my opinion.

As a sidenote...0 gauge isn't completely necessary for the big three, especially if you haven't upgraded your alt. The best thing to do is just add 4ga to your factory wiring. Stripping and crimping 0ga is a beast!!
 

Gold Member
Username: Ctmike

Ct.

Post Number: 1232
Registered: Feb-06
well you could look at your alt. to see how big it is, or if you have the money and to save yourself trouble in the future if you plan on upgrading your system, just get a ho alt. now. but like i said running 600w should be no problem at all.
 

Bronze Member
Username: Saoxcore

Post Number: 49
Registered: Jul-06
yeah. i was just a little worried cause in my dash it shows the battery only being half way powered, or whatever. and i dont know if thats low, or normal, or what. and i read thingsa bout people needing a new battery and what not.
 

Gold Member
Username: Illuminator

USA

Post Number: 3840
Registered: Apr-05
It's a monitor of the voltage coming from the alternator. Halfway means normal.

If your car was using power from the battery, the battery indicator light would come on and you would have an electrical problem on your hands...
 

Gold Member
Username: Ctmike

Ct.

Post Number: 1233
Registered: Feb-06
you should be fine with stock everything in your car, maybe upgrade your battery if you want, but 600wrms isn't that much. but if you want, you could upgrade everything, if you have the money, and not have to worry about it later if you want to upgrade your system.
 

Bronze Member
Username: Saoxcore

Post Number: 52
Registered: Jul-06
okay good. i have that worry out of my mind.
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