Official CarAudio.com Big 3 Thread

[LeofromtheH 10+ year member]

that wire looks like spagetti. i bet it's super easy to work with. i had a somewhat hard time twisting and turning the welding supply wire to where i wanted it. here's some pics

fuse on other side of those zipties

dirty hands ftl

 

[iwanturmags 10+ year member]

Ok so Battery ground to chassis.

Alt Pos to Battery pos.

Engine block Neg to Chass.

Is that it in lamens?

 

[da12b 10+ year member]

yep, you got it.

 

[iwanturmags 10+ year member]

I read 8 of the 13 pages and did not find an answer to: my alternator is only 105 amps, does have a low power alternator negatve the effect of The Big 3? I mean it doesn't seem like it would but better safe then sorry.

 

[PollyCranopolis 10+ year member]

I wouldnt call that low power. Many people run off 60 amp alts all day long, and still do the big 3. I have a 70 amp in my civic.

 

[theothermike 10+ year member]

informed from a guy with much more intellect then me that i need 2 fuse holders on the alt to batt run. 1 near alt, 1 near batt. that way where ever the short is coming from, im safe.

question is why wouldnt 1 work? in middle, or more towards battery?

Mike-

 

[johnecon2001 5,000+ posts]

He would be correct in a dual battery situation where power is running both ways (to and from each battery). In this case though, power is flowing away from the alternator towards the battery. Thus only one fuse, in the middle is required.

And don't let some of these hippies tell you you don't need a fuse. EVERY car already has a fuse on the existing alternator wire in the fuse box. Its marked "alternator".

 

[phenryiv1 10+ year member]

I read most of this thread, but after a few pages of the same things over and over again, I gave up.

I am SURE that somewhere in this thread, at least one of these questions are already answered, but "Search" just led me back to the thread as a whole...

1, Will upgrading my battery terminals help with this effort?

2, Are there any other grounding points that I might want/need?

3, If I have a 3-4 foot run of 1/0 from batt to alternator, what amperage of fuse do I need?

Thanks!

 

[Team Hammer 10+ year member]

I read most of this thread, but after a few pages of the same things over and over again, I gave up.
I am SURE that somewhere in this thread, at least one of these questions are already answered, but "Search" just led me back to the thread as a whole...

1, Will upgrading my battery terminals help with this effort?

2, Are there any other grounding points that I might want/need?

3, If I have a 3-4 foot run of 1/0 from batt to alternator, what amperage of fuse do I need?

Thanks!

Adding Battery Terminals That Can except 1/0 and #4 makes it easier to wire.

Battery Neg is the best choice then Frame or Engine.

1/0 can be 250amp or 300amp.

Also fuse the battery to Dist block run. Install the fuse as close to Battery as you can.

 

[tebo7 10+ year member]

I have 2 Rockford 12" Stage 3 in my Honda Accord.

When i turn the volume up the lights don't dimm.

Does The big 3 will help to get more power to the amp?

do i need to do the big 3 ?

 

[phenryiv1 10+ year member]

Adding Battery Terminals That Can except 1/0 and #4 makes it easier to wire.
Battery Neg is the best choice then Frame or Engine.

1/0 can be 250amp or 300amp.

Also fuse the battery to Dist block run. Install the fuse as close to Battery as you can.

Thanks. I think that I found batt terminals that hava a single 1/0, a single 4, and (2) 8 ga. holes. That will be perfect for my application.

What do you mean the batt to d-block run? My 4-gauge run will go to a single 4 channel amp, and of course it will be fused at both ends. Is there another d-block that I should be using?

 

[hotbodkev]

I have 2 Rockford 12" Stage 3 in my Honda Accord.When i turn the volume up the lights don't dimm.

Does The big 3 will help to get more power to the amp?

do i need to do the big 3 ?

doing the big 3 wil not hurt it will only help you. do it.

 

[da12b 10+ year member]

I have 2 Rockford 12" Stage 3 in my Honda Accord.When i turn the volume up the lights don't dimm.

Does The big 3 will help to get more power to the amp?

do i need to do the big 3 ?

If you want more power, get a bigger amp. The "big 3", to my understanding, will decrease the internal resistence, therefore making the voltage drop less. If you upgraded the "big 3" and the battery, and your lights still dims, you might want to consider getting a H.O. alternator.

 

[Team Hammer 10+ year member]

Thanks. I think that I found batt terminals that hava a single 1/0, a single 4, and (2) 8 ga. holes. That will be perfect for my application.
What do you mean the batt to d-block run? My 4-gauge run will go to a single 4 channel amp, and of course it will be fused at both ends. Is there another d-block that I should be using?

Install a fuse from battery, Then the Dist Block should be a fusable type. I use ANL that takes Two 1/0 in and Two #4 outs. Mine are Pos/Neg built-in to the block.

The way it works is You have Two Pos inputs and Two Neg Inputs 1/0 or #4 with a barrel Reducer, All in the same block. I use this type to break the wire size down for branching off.

 

[phenryiv1 10+ year member]

Alright, I have an arguement that I need you guys to help me settle.

After reading ALL 13 pages, it says in here numerous times to fuse to the wire, not to the alternator. Fair enough- I did that. I posted my pics and my writeup on a forum specific to my vehicle. In one of the pics, you can see my 200A fuse for the batt--->alternator wire. That sent people into a tizzy. Their argument:

Is that a 200A fuse there? WTH would you need a 200A fuse. As good as no fuse. I use a 100A fuse w/ no problems whatsoever...

I responded that I had read on here and on sounddomain to fuse to the wire and not to the alternator. His response:

That makes no sense. If your alternator goes to hell and spikes 150A say good buy to the electical componets of your car.

Then, a second guy chimed in:

Just want to say that he (First Sentra Guy) is right here. In my recent accident I had a wire going from alt+ to bat+ and something shorted out in my electrical system and set the engine on fire (right on the alternator). I can't help but think this might have been because of this extra wire (which was not fused) and a 200A fuse is gonna do about the same.

So it got me thinking- WHY do we fuse to the wire and not to a rating just above the rated output capacity of the alternator? Since in theory, anything ABOVE the rated output from the Alt SHOULD blow your factory fuse, you have effectively sidestepped that safety device (the factory fuse) and now we have exposed the OEM electrical components to a spike or surge that it is not designed to take.

I want to think that the advice that I get on a car audio forum is more accurate than that on a general automotive forums, as it applies to 12V matters, but I wanted to see if anyone here could give me some supporting info on WHY we fuse to the wire, regardless of the factory wiring and electronics capacities.