THE BIG 3

[Aaron Clinton 2,372]

i was thinking of a second battery but have no where to put one but maybe under one of my front seats? i was also thinking of a kinetik hc 600 or 800 because they arent very big and easier for me to hide, but im not sure

maybe look into a BATTCAP, I have not used them but they are small and can put out big current

[j_a_trevino 0]

i will check those out thanks!

[carguy6702 0]

got a question why do i need a fuse between batt. and alt.

[///M5 2,833]

got a question why do i need a fuse between batt. and alt.

Same reason you need a fuse anywhere, but of course they don't use one at the factory so if you are good with your wiring you can get away without it.

[carguy6702 0]

thanx

[crunch1 0]

if memory serves me correct when excited the free electron in copper travels along the outside surface of the wire, so there for, the more surface area the better transfer of electrons. Multi-stranded copper wire has a better surface area than solid wire. Strand count isnt just a term for how flexible the wire is. Keep this in mind when buying alternative wire not designed for optimum power transfer. Ex: wire designed for welders. Dont get me wrong im sure it will work just fine, but when your trying to squeeze out every ounce of voltage you can I would use a power cable designed for audio power transfer IMHO.

Now about the fuse in the alt line. For optimum power transfer a fuse is nothing more than a bottle neck. I know the fuse is a good idea for protecting the alt if a accidental grounding occurs, but your never going to achieve maximum continuity. IMHO

[DevilDriver 28]

if memory serves me correct when excited the free electron in copper travels along the outside surface of the wire, so there for, the more surface area the better transfer of electrons. Multi-stranded copper wire has a better surface area than solid wire. Strand count isnt just a term for how flexible the wire is. Keep this in mind when buying alternative wire not designed for optimum power transfer. Ex: wire designed for welders. Dont get me wrong im sure it will work just fine, but when your trying to squeeze out every ounce of voltage you can I would use a power cable designed for audio power transfer IMHO.

Now about the fuse in the alt line. For optimum power transfer a fuse is nothing more than a bottle neck. I know the fuse is a good idea for protecting the alt if a accidental grounding occurs, but your never going to achieve maximum continuity. IMHO

This is substantially more noticeable at high frequencies (the skin depth of copper at 60Hz is just over 8mm whereas at 10kHz it is just over 0.6mm iirc), with larger amounts of current, or with much lower gauge wires. In a vehicle, it is really unimportant, and the difference between welding wire and "audio power wire" is usually the jacket.

[crunch1 0]

nice one DD you got me thinking. I have already dismissed OFC as a purchasing factor, because the only benefit is at very high temperatures such as what happens in engine windings the OFC wire is less brittle so basically there is no difference in conductivity over regular annealed copper. I was just down to the skin factor of annealed copper and different sheathing. heh

[Tommythecat 0]

DevilDriver, the difference in welding wire and "car audio wire" is strand count. More strands = more flexibility. The cost of, say, Kicker Hyperflex could be worth it to someone if they need/want a flexible wire vs welding wire which is very stiff.

[DevilDriver 28]

DevilDriver, the difference in welding wire and "car audio wire" is strand count. More strands = more flexibility. The cost of, say, Kicker Hyperflex could be worth it to someone if they need/want a flexible wire vs welding wire which is very stiff.

The HyperFlex is a big difference; I agree with you there totally and love the stuff. I've held a lot of wire from other companies, though, that has virtually identical strand count as welding wire.

[JEREMIAH 0]

.......;lasdvoiajltnmsl;cjvmoifgaergjcfgeklg < that's me right now!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!11

[Mesto 0]

How come I can't view the attached pictures?!

[johnecon2001 82]

because whatever hosting service that hosted them probably deleted them.

[mazdaboom 0]

ive done the big three on my previous vehicles and now i have a diesel truck with two batteries is there anything extra that i am going to have to do with it? like is it gonna turn into the big six lol

[osixfrontier 0]

JSUT CURIOUS ON HOW BIG THE FUSES SHOULD BE FOR THE WIRES? 150 AMP?FOR THE STALK ALT IS GOOD OR SMALLER?

[fbi90909 0]

JSUT CURIOUS ON HOW BIG THE FUSES SHOULD BE FOR THE WIRES? 150 AMP?FOR THE STALK ALT IS GOOD OR SMALLER?

depends on what amperage output your alt does. if you put lets say for example a 100amp fuse in line when you have a stock 130amp alt, when the alt starts producing max voltage the fuse will pop.

but if you have lets say a 100amp fuse and an 80amp stock alt. then your good to go.

check what your stock alt is rated to do, than just go a bit above it.

[johnecon2001 82]

JSUT CURIOUS ON HOW BIG THE FUSES SHOULD BE FOR THE WIRES? 150 AMP?FOR THE STALK ALT IS GOOD OR SMALLER?

depends on what amperage output your alt does. if you put lets say for example a 100amp fuse in line when you have a stock 130amp alt, when the alt starts producing max voltage the fuse will pop.

but if you have lets say a 100amp fuse and an 80amp stock alt. then your good to go.

check what your stock alt is rated to do, than just go a bit above it.

That's not entirely accurate. If you have a 130a alt you should be using at least 4awg. When you run 4awg, you should fuse it to 150a. Of course, with the big three, the maximum wire siz you can afford should be used (most people use 1/0awg). You can fuse 1/0awg up to 350a.

[cx-7heaven 7]

Ok guys, maybe you can help me. I have an '07 mazda cx-7. It has a "pd drive" alternator setup. What it does is go through the computer, and the comp decides where and how much amperage to send out. What would happen if I go from the alt positive directly to the batt positive, in effect bypassing the computer? BTW the info on the pd drive is straight from the owner of ohio generator.

Thanks for any help

Edited November 30, 2007 by cx-7heaven

[cx-7heaven 7]

Devildriver, you know anything about this?

[fbi90909 0]

Ok guys, maybe you can help me. I have an '07 mazda cx-7. It has a "pd drive" alternator setup. What it does is go through the computer, and the comp decides where and how much amperage to send out. What would happen if I go from the alt positive directly to the batt positive, in effect bypassing the computer? BTW the info on the pd drive is straight from the owner of ohio generator.

Thanks for any help

i have a feeling that what you have on your car is similar to what my car does. my car has an ELD(electronic load detector) in conjucntion with an ECU(electronic control unit). well what is is the ELD is a little unit that sits in my fuse box, and when it detects a pull of a turned on unit inside the car that uses up a decent amount of voltage it sends a signal to the ECU which that tells the car to run the alt to produce extra voltage for the detected load.

for example. power windows has a fuse in my fuse box. normally my voltage sits around 12.3-12.4. if i do something with the window of putting them down or up it detects a laod of needed voltage and would cause my alternator to kick in for the needed voltage, but as soon as i let go of the button and the ELD doesn't see any needed load it just tells the ECU to stop the alt.

but to the point. you could run the big 3 direct to the batt. when the PD drive in the car kicks the alt in to produce the needed voltage for w/e you are running in the car it will feed that unit + feed the battery at the same time. basically bypassing the PD drive. only problem is you will most likely not get full alternator output as your PD drive was probrably set in the car so the car runs as effecient as possible, and to save on gas.

just so you knwo i'm not 100% about your car, but the PD drive you state sounds something similar to what my car does. it just doesn't direct voltage.

though, it's still ok to run Alt to Batt.

[InfinitePeace 0]

I posted this on another forum and just wanted to repost it here to add to this discussion.

I bought a 180a from Ohio General and they told me more than once, upgrade to the largest size of cable that you can for everything more or less EXCEPT the Alt to Batt Pos. They told me, which I confirmed multiple times, on a short run, 4awg (at least for upwards of 200a) is plenty and ideal; they don't recommend larger than that in that location because the size of the post on the alternator is too small to bind to the larger wire; ergo because of the size difference, the post on the alt heats up too much and can overheat it. That was their recommendation and I'm going to have the shop that is doing it for me talk to them and confirm with a detailed description of my specific engine.

The other interesting thing they said was do NOT fuse that wire. I confirmed this as well, DO NOT fuse this wire because if for some reason it does indeed blow, the alternator will no longer see the battery and think that it's dead, so it will kick into high gear and stay that way until it burns up because it will never see that battery again until you've changed that fuse, thus leaving you with a dead battery and a burnt out alternator.

[jonbearsmt 919]

ive done the big three on my previous vehicles and now i have a diesel truck with two batteries is there anything extra that i am going to have to do with it? like is it gonna turn into the big six lol

yup big six... and most pick up diesel trucks have very low cranking amps. usualy 400 or so each... so you will need to get some larger ones.

[timmc2006 0]

The Big 3 Are:

1. negative battery wire to ground - just replace the negative batt. terminal and wire and ground it to the factory location

2. engine block to ground - replace the ground wire from the engine block to the chasie with a bigger wire (maybe 4 guage)

3. alternator to batt - add a fused wire from the postive post on you alternator (the one comming from the battery) to the postive terminal on your battery. DO NOT exchange wires just add a extra one. make sure it fused the same size as your factory fuse.

hope thats helps

Note on #2- Some cars have a batt-engine block connection stead of chassis to engine block...

Some cars have a batt-engine block connection stead of chassis to engine block... what does this mean cause i cant find a ground coming from my engine but there is a ground from my negative side of my battery to the body then to the motor mount why is it like that?? any idea would be great and if it would help it is a 02 nissan sentra

[fuzzyping 0]

I'm trying to determine what my next step should be. My 2002 4Runner has a Sundown Audio SAX-100.4 on the front components, and had a Sundown Audio SAZ-1500D on the subwoofer. However, it appears my wiring is insufficient as I burnt the 1500D a while back (running sub-less for months now). I'm not sure what steps I should take to avoid this in the future. I have the stock battery and alternator, with 4-gauge to blocks and 8-gauge to each amp. In hindsight, this is terribly inadequate, but we only learn from our mistakes.

What steps should I take next? Should I add a dedicated run from the main battery to the 1500D? If so, which gauge? Should I do the "BIG-3" or install a 2nd battery in the back? I presume it's some combination of these, but I'm clueless. Any help would be greatly appreciated.

Thanks,

-fp

[Aaron Clinton 2,372]

Jason, I think I mentioned it before, instead of pulling the existing wire out, leave it for the 100.4. Then run 1/0 for the 1500D, and ground it in the rear. But yeah, do the big 3 and get more out of what you have, then go from there.