Official CarAudio.com Big 3 Thread

[jco1385 5,000+ posts]

i would just leave it the way it is. unless the stock wires are corroded/cracked/exposed or otherwise in NEED of being replaced i would leave them.

even if you want to pull the stock wires, 1 short run of 1/0 will be more than you'll ever need for your alt. or any of the big 3

got extra wire? send it to me... //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[loopkiller 10+ year member]

got extra wire? send it to me... //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

//content.invisioncic.com/y282845/emoticons/nono.gif.eca61d170185779e0921b0faa9704973.gif

 

[jco1385 5,000+ posts]

hey, i got somewhere you can... wait....

//content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[kotag]

how does the alt put out power w/o a complete circuit? a sure as hell cant think of a way that could possibly work
EDIT:

actually, if the alt case is metal, and the engine/alt bracket is metal... then the alt case = the engine (electrically). so engine to chassis = alt case to chassis (electrically)

You left me with the doubt about this so I went and remove my alt and turns out you're right.

There are two posts outside the alt, one is pos and goes to the bat and the other (which i thought it was neg) turns out to be the protection circuit. In the inside the alt is wired so the alt case (which is metal) does the ground for the alt in union with the engine block, brackets and bolts.

Just as you said before THANKS for the help //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[jco1385 5,000+ posts]

i knew that didnt sound right.

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[Proximity 10+ year member]

Are there any before/after type things with a multimeter you can do to see how helpful your efforts have been with the big 3?

 

[jco1385 5,000+ posts]

i don't have any. but some folks have done that. there are so many "big 3" threads started it'd probably take all day to find any of them though //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[kopimon 10+ year member]

Anyone have a mirror of this tutorial somewhere? The pictures don't work.

 

[dman4486 5,000+ posts]

whadaya mean pics don't work

http://www.caraudio.com/forum/showpost.php?p=5762107&postcount=571

 

[kopimon 10+ year member]

whadaya mean pics don't work
http://www.caraudio.com/forum/showpost.php?p=5762107&postcount=571

The ones in the first post didn't work. I didn't actually read this entire thread. Thanks for that link.

 

[McIntosh 10+ year member]

[quote name=johnecon2001;1681655Replacing/adding larger wire to these three critical spots can reduce or rid your electrical system of dimming and voltage drops. Overall' date=' giving your charging system a larger surface area to travel over, will stabilize power and relieve strain on the alternator and battery.

(continued in next post)[/quote]

While some of this is true (the first sentence), the rest is not. Splain to me how requiring more current out of both your battery and alternator will "relieve strain" on them. You're taxing them more, not "relieving strain". I wonder how many stock alternators fried prematurely because of this great "mod". This is how those stupid engineers designed it to work: The battery provides a large reservoir of power to start the engine (hence the larger cables to the starter and ground than from the alternator). Once the engine is running, the alternator can provide all necessary power plus more to recharge the battery, less at idle when the battery again assists. The alternator is not sized/designed to provide 100% duty cycle (ie its rated output all the time). They're not designed for powering "large" amplifiers, they're to keep your lights on and your battery charged for the life of your car. If you do the "big 3" without getting a larger alternator you're shooting yourself in the foot. Adding another battery only worsens the situation (unless you only want to use your stereo a percentage of the time and charge the batteries the rest of the time). It should be the "big 4" with a HO alternator added at the same time.

 

[kopimon 10+ year member]

While some of this is true (the first sentence), the rest is not. Splain to me how requiring more current out of both your battery and alternator will "relieve strain" on them. You're taxing them more, not "relieving strain". I wonder how many stock alternators fried prematurely because of this great "mod". This is how those stupid engineers designed it to work: The battery provides a large reservoir of power to start the engine (hence the larger cables to the starter and ground than from the alternator). Once the engine is running, the alternator can provide all necessary power plus more to recharge the battery, less at idle when the battery again assists. The alternator is not sized/designed to provide 100% duty cycle (ie its rated output all the time). They're not designed for powering "large" amplifiers, they're to keep your lights on and your battery charged for the life of your car. If you do the "big 3" without getting a larger alternator you're shooting yourself in the foot. Adding another battery only worsens the situation (unless you only want to use your stereo a percentage of the time and charge the batteries the rest of the time). It should be the "big 4" with a HO alternator added at the same time.

Alternators can provide much more power than you think. If you have a 4x75W RMS amplifier and a 1x400W RMS amplifier, that's 700W RMS. Let's assume the amps are only 80% efficient, so 560W RMS.

Average output voltage of an alternator is 13.8V, so 560/13.8=40.5A. Considering that music signals use 1/3rd the average power of a test tone, that brings you down to 40.5/3 = 13.52 amps.

My numbers were off the top of my head, but it's enough to make my point. While your car is running it uses about 40% of the alternator's available output current (more when you have the AC on), so any modern car should be able to handle a basic system with no problem.

Adding a larger wire doesn't make the alternator put out its max current all the time. It just provides a less-resistive path for the electricity to flow, meaning more and cleaner power gets to the amps (and the rest of the car).

 

[jco1385 5,000+ posts]

While some of this is true (the first sentence), the rest is not. Splain to me how requiring more current out of both your battery and alternator will "relieve strain" on them. You're taxing them more, not "relieving strain". I wonder how many stock alternators fried prematurely because of this great "mod". This is how those stupid engineers designed it to work: The battery provides a large reservoir of power to start the engine (hence the larger cables to the starter and ground than from the alternator). Once the engine is running, the alternator can provide all necessary power plus more to recharge the battery, less at idle when the battery again assists. The alternator is not sized/designed to provide 100% duty cycle (ie its rated output all the time). They're not designed for powering "large" amplifiers, they're to keep your lights on and your battery charged for the life of your car. If you do the "big 3" without getting a larger alternator you're shooting yourself in the foot. Adding another battery only worsens the situation (unless you only want to use your stereo a percentage of the time and charge the batteries the rest of the time). It should be the "big 4" with a HO alternator added at the same time.

you are not needed in this thread. we got this //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[smoka 10+ year member]

Splain to me how requiring more current out of both your battery and alternator will "relieve strain" on them. You're taxing them more, not "relieving strain".

Explain to me how installing a larger wire (big 3) causes "more current out of both your battery and alternator"?

Installing larger wire does NOT cause you to pull more current. //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif The current stays the same, but the larger wire has less resistance which means you don't have as much of a voltage drop.

To say that an alt would ever run at 100% continuously is just stupid.

Anybody who gets that much power to max out their alt continuously (my guess would have to be over 2kwrms and listens to test tones all day //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif) usually upgrades their alt anyway.

But for the average enthusiast, the big 3 is a cheap and easy way to avoid unnecessary voltage drop due to undersized wires.

 

[McIntosh 10+ year member]

Alternators can provide much more power than you think. If you have a 4x75W RMS amplifier and a 1x400W RMS amplifier, that's 700W RMS. Let's assume the amps are only 80% efficient, so 560W RMS.
Average output voltage of an alternator is 13.8V, so 560/13.8=40.5A. Considering that music signals use 1/3rd the average power of a test tone, that brings you down to 40.5/3 = 13.52 amps.

My numbers were off the top of my head, but it's enough to make my point. While your car is running it uses about 40% of the alternator's available output current (more when you have the AC on), so any modern car should be able to handle a basic system with no problem.

Adding a larger wire doesn't make the alternator put out its max current all the time. It just provides a less-resistive path for the electricity to flow, meaning more and cleaner power gets to the amps (and the rest of the car).

Your math is a bit flawed. An amp draws more power than it outputs, not less. Using your numbers you'd divide 700 by .8, not multiply (and 80% is being pretty generous). I'm also unsure where your 40% load for the alternator came from as there a lot of variable loads larger than an A/C compressor clutch. Start your car on a cold winter night, turn on headlights, rear defroster, heater blower, stereo AND charge the battery. Its gonna be pretty maxed out. At the other extreme starting your car on a warm summer day and turning the A/C and stereo on will be much less than 40%. My point certainly wasn't that increasing the wire size from the alternator to the battery would cause it to output 100% capacity, rather that the wire size is correct for the alternator's 100% capacity. If you install a HO alternator, you certainly will gain by increasing the wire size. Your definition of "basic system" is also an unknown. I'll try to reword my intent: Increasing the wire size from the alternator will not increase it's output by any meaningful amount. Increasing the battery wires' size WILL, but you'll be discharging your battery all the time if you don't get a HO alternator. If you just turn it up occaisionally (then turn it down for a longer time to actually let the alternator charge the battery) I guess you're "gaining" something (impressing people at stoplights?). Installing amps that draw too high a percentage of the alternator's output will ensure three things: Your alternator will fail prematurely, your battery will never be fully charged (and will fail prematurely) and your voltage will be reduced at the point of utilization (unless you only crank it at stoplights). As to how much stereo power over stock is an acceptable load? More variables, of course. The bean counters don't allow too much "over-engineering" nowadays. Weight (MPG), production cost (and subsequent consumer cost), etc have been cut to bare bones for economic reasons. Its profit driven, they're not going to give you too much more than you actually need. A turnip only holds so much blood.