# Capacitor Question



## Bumpin (Feb 18, 2003)

Would it be wise and safe using a 3+ farad cap instead of 2 separate batteries?


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## dundee (May 11, 2002)

the keyword there is "instead". It depends on the problem you are trying to solve... give me more info.


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## Bumpin (Feb 18, 2003)

Dimming lights.


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## dundee (May 11, 2002)

A cap for sure. Use very short thick wire and connect it in parallel to the power inputs to your sub amp.


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## Matt93SE (Sep 17, 2003)

not just your sub amp, but run it to the distro block of the entire system. works better that way for the whole car, not just the sub amp.


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## Bumpin (Feb 18, 2003)

Well I use a circuit breaker, so I should run it...

Battery ---> Circuit Breaker --> 3 farad cap --> Distributor block --> Amps

That way right? This would be better than running a second battery and isolator?


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## dundee (May 11, 2002)

-- how many amps do you have for your subs?

-- the cap is what will solve your light dimming problems

-- the only thing a 2nd battery is going to give you is longer play time with the engine off


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## dundee (May 11, 2002)

how many amps total and give a few more details about the speakers they are driving


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## Bumpin (Feb 18, 2003)

2 amps total. One 2400 watt amp for subs and 1000 watt amp for high's. The amp for the subs is pushing 2 Crystal CMP x2 subs and the amp for the high's are going to be pushing Crystal comps and coaxials.


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## dundee (May 11, 2002)

As long as your amps and distro block are all next to each other and wiring is kept short and low gauge it will be would be fine to hook it in parallel before the distro block.

I dont think those power ratings are very accurate for those amps by the way. (Car audio stuff uses a lot of tricky in calculating P=IV). But if they are you'll need a high output alternator with to go with that cap.


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## sr20dem0n (Mar 19, 2003)

A second battery will do more than allow you to play longer with the car off. A pair of batteries will have a stronger skin charge than a single, whether it's as strong as a 3 farad cap I don't know, but compared to the current draw of those amps, the energy a 3 farad cap is capable of storing is laughable. It might help though....


Have you upgraded the big 3 yet? That will have more of an impact than any cap will, and it's only about $10.


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## dundee (May 11, 2002)

sr20dem0n, what do you mean by skin charge? do you mean current sink cappability?


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## Bumpin (Feb 18, 2003)

sr20dem0n said:


> A second battery will do more than allow you to play longer with the car off. A pair of batteries will have a stronger skin charge than a single, whether it's as strong as a 3 farad cap I don't know, but compared to the current draw of those amps, the energy a 3 farad cap is capable of storing is laughable. It might help though....
> 
> 
> Have you upgraded the big 3 yet? That will have more of an impact than any cap will, and it's only about $10.


I havn't upgraded anything yet because I don't want to waste money. If 2 batteries would be better i'm going to get 2 optimas, but if not, I am going to get a 3 farad cap. That's why i'm asking this question before I purchase anything.


And dundee, my amps are Orion and Us Acoustic, so the rating might not be accurate on the US, but i'm pretty sure its accurate on the Orion.


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## sr20dem0n (Mar 19, 2003)

dundee said:


> sr20dem0n, what do you mean by skin charge? do you mean current sink cappability?


When you hook a car battery up to a high voltage source (like the alternator), once it's full it will "overcharge" and actually sit at the alternator's voltage, even after you turn off the car. After you turn off the car the skin charge can last for hours before the battery voltage finally drops back to 12.5V. You can actually turn off the car and play the system with a voltmeter hooked up to the battery and watch the voltage slowly trickle back down to 12.5V where it sits until the battery is almost dead and it starts dropping lower. If you aren't listening to the music loud the battery could stay at 14V for a minute or so, or if you have it cranked up it may drop back to 12.5V after the first big draw. When the car is running and you have a big current draw, that will draw current from the battery's skin charge as well as the alternator, if the draw is big enough then the voltage will drop down to the battery's real voltage where it can take care of the rest. When you have 2 batteries, you have twice the energy stored in that skin charge, and it may do the trick. Same effect as a capacitor really, but I'm not sure if it can hold more or less energy than a capacitor can.


Either way, upgrade the big 3 before you do anything, you might not have any dimming problems afterwards and you might not even need a cap or a battery.


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## dundee (May 11, 2002)

Trust me the capacitor is going to solve the dimming light problem. If you really want I can explain all the electrical engineering concepts to prove this.

Both amps are not putting out that much power. A more realistic number can be obtained by summing how much RMS power is being sent to each speaker (remember to account for bridged channels, and the resistance (Ohms) each channel is driving). If you want I can help you if you give me the the exact model number of the amps and how they are wired to the speakers.


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## xbrandonx (Mar 27, 2004)

dundee said:


> Trust me the capacitor is going to solve the dimming light problem. If you really want I can explain all the electrical engineering concepts to prove this.
> 
> Both amps are not putting out that much power. A more realistic number can be obtained by summing how much RMS power is being sent to each speaker (remember to account for bridged channels, and the resistance (Ohms) each channel is driving). If you want I can help you if you give me the the exact model number of the amps and how they are wired to the speakers.


however a cap will cost more then just the $10 upgrading the big 3 grounds will.

and you don't want the cap in line with the amp going to your highs.

its more like this:

battery - Circuit Breaker - Distributor block - 3 farad cap - amp to subs
____________________________________ - amp to speakers


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## dundee (May 11, 2002)

sr20dem0n, ok I did a little searching around on this "skin charge" stuff you crazy guy...  I getting flash backs of my electro-magnetics class with good old Dr. Jordan. To put is a simply as I can what is happening is a charge (a bunch of electrons) is building on the plates inside the battery because the alt is outputting 14.4v and the other internals are at a lower potential of 12v. Image a mini capacitor inside your battery. This is why you get that "skin charge." Now this is NOT a suitable replacement for a capacitor that is designed for a fast response to large current draw like the electrolytic ones that car audio people use. See anything in this world can act like a capacitor if placed & insulated next something with a lower potential. The usefulness of such capacitor vary on a large scale. The key in this situation is related to time or otherwise known as transitient response. To solve to dimming light problem you would want a capacitor fast response time as close as possible to the amps. I hope that made sense.


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## xbrandonx (Mar 27, 2004)

dundee said:


> To solve to dimming light problem you would want a capacitor fast response time as close as possible to the amps. I hope that made sense.


he may not need to go as far as getting a capacitor though.

he may be able to take care of the problem for just a few bucks by upgrading the grounding system on his car.

Being that you car is 6 years old, I'm sure there is some corrision starting to build up on your grounds.


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## dundee (May 11, 2002)

Jeez.... now we're talking about resistance eh???? lol The big 3 grounds will basically lower the resistance between the alternator, battery and the chassis were all of the cars electrical components are grounded as well as the amps. So you guys are correct this will help the power to be distributed more effientially thoughout the car. It will help Bumpin's problem... I cant say if it will solve it though.


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## sr20dem0n (Mar 19, 2003)

dundee said:


> sr20dem0n, ok I did a little searching around on this "skin charge" stuff you crazy guy...  I getting flash backs of my electro-magnetics class with good old Dr. Jordan. To put is a simply as I can what is happening is a charge (a bunch of electrons) is building on the plates inside the battery because the alt is outputting 14.4v and the other internals are at a lower potential of 12v. Image a mini capacitor inside your battery. This is why you get that "skin charge." Now this is NOT a suitable replacement for a capacitor that is designed for a fast response to large current draw like the electrolytic ones that car audio people use. See anything in this world can act like a capacitor if placed & insulated next something with a lower potential. The usefulness of such capacitor vary on a large scale. The key in this situation is related to time or otherwise known as transitient response. To solve to dimming light problem you would want a capacitor fast response time as close as possible to the amps. I hope that made sense.



I'm an electrical engineer (er, will be in about 7 months). I was trying to explain it simply to you, didn't realize you knew electronics as well 


Capacitors aren't the end-all be-all solution to dimming. The large capacitors used for this kind of application have a very large ESR which hurts their performance. While this isn't as much of an issue with caps such as these, it's a huge issue with the carbon caps that a lot of people get (normally 20+ farad, though because they have such a huge ESR they're actually less effective than the smaller ones). This isn't the type of cap he's looking at I hope, but if it is he should definitely reconsider.

Anyway, it really depends on what the source of the dimming is. If he's got a strong alternator, good battery, and good wiring, then yes a capacitor can help the electrical system respond to transients faster. But with most electrical systems the weak link is the grounding, I can't stress enough how poor the stock grounds are. A lot of times the dimming problems people have are simply a result of their voltage being burned off in the car's wiring when the amps draw a large amount of current. What's the point in using 1/0awg back to your amp and from the amp to the chassis if you've got a dinky little 8awg that's 3 feet long and has terrible connections running from the chassis up to the battery? By upgrading the wiring, they fix the problem at its source. A cap could be used in this situation with decent results, but it would really just be an expensive bandaid covering up another (and cheaper to fix) problem.


And his sub amp does 2400x1 @ 1ohm, which I do believe he's running it at. Yes that's RMS, you'll never find me quoting peak values. Not sure about the other amp, but normally the front stage amp doesn't affect the electrical system much, the amount of average power required to reach a good listening volume on mids/highs is pretty low.


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## Bumpin (Feb 18, 2003)

Actually it's 2400x1 @ 2ohm. It's the older Orion amp, the newer ones (2500D) do 1 ohm and can even handle .5 ohm.


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## dundee (May 11, 2002)

sr20dem0n, thats hilarious youre an EE. I was struggling trying to expand guasian surfaces so I used the mini capicator idea. The only thing I hate about my job (and I LOVE my job) is explaining EE concepts to the bossman. So I've gotten used to relating it to Engines, PCs or whatever. I work for a small startup and I'm the chief EE and only engineer, lol. I do robotic and automotion... which means I have to dive into many areas of EE and even ME. FPGAs, MCUs, DSPs, High Power Motor Drivers, Freaking annoying electrical noise problems, Motion Control Algrothims, Turning motors, calculating power and torque needed, yadda yadda, on and on... I love it! :thumbup: 

Anyway back to the problem, yeah give the grounds a once over and lower that resistance. That is very important and I totally agree.

This is in that civic I presume, eh? Well I wouldnt hold that against ya. I actually always thought the 99' si with the B16 was kinda cool. (keyword: kinda). Anyway in that case the stock alternator is good for 70,75 or 80 amps from what I found searching for replacements. So lets do the calculations:

MAX TOTAL power from the alternator would be AMPS x VOLTAGE. Lets think postive and use 80A and 14V. (80A)(14V) = 1120 Watts of power @ 14V DC. DC is the keyword there.

Now youre not just running a audio system here... you have to make that little B16 happy, run those damn headlights, foglights, brakelights, parking lights, ECU, Airbag, etc, etc. I dont know exactly how much all that takes but if the engineers at Honda are halfway intellegent they would have figured out how much power all the stock stuff draws and then selected a alternator with approx 25% more power than required. So with that assumtion I'd say you have about (1120w)(.25) = 280w for you audio system again at DC (remember that keyword).

So why then is your 2400w amp working when the alty can only spare 280w? DC power remember? Whats RMS power? Root Mean Squared. blah blah blah stuff you dont want to hear stuff I dont want to explain.  RMS Power is the same amount of power though a load as the average DC power through the same load. UH? RMS is used for measuring AC Power. For example nice and consisent 120v @ 60Hz out of the wall. That is a wave repeating at 60Hz all the time. Music does not play at the same frequency all the time. That would be boring. So the big bass hits are in time to music beat which does not stay consisent (not in EE terms!!).

We'll get back to that. You're getting spikes of power during those bass hits that are making your headlights dim in time to the music. Why? Thats when the alternator cannot supply anymore power. So the amp is asking for more power where does it get it from to finish off the bass hit (which probably will be less forcefull)? Ahh.. the battery. But the battery is 12v. The alternator's output voltage will drop because it is outside of its rated power range until it reaches 12v. When it reaches 12v (It will dip slightly below this first) the battery will be at a higher or equal potential to the alty and supply extra current to the amp and the rest of the car. So thats why your headlights dim, the voltage to them is lower (~12v) during the bass hit.

How do we fix this... First the thing I did not point out. Make sure the pathways for your electrical connections have as low a resistance as possible. Low gauge, short length, solid rust free conectors. This includes the stock power wiring "the big 3". Extra resistance will cause power to be lost in the form of heat not bass. 

Next, remember that whole RMS & DC power crap. ok well your little alty can only spare 280 watts of DC power. but those bass hits arent exactly DC or are they nice a consisent small hits (RMS), huh? think of the capacitor as a temporary "battery" only to be used during that big bass hits and in the inbetween time it charges really fast up to 14v when the alty has spare power. by placing that capacitor inline with the sub amp. the alternator "sees" an amp that is asking for power levels that are averged or smoothed out (almost DC) over time. so it can run that large amp without hopefully dimming the headlights.

There is a limit to this solution. A very large amp will ask for so much power from the cap that is will drain that, then start asking the alternator, max that out, then start asking the battery all in one bass hit!!! What to do now? You guessed it bigger alternator. OK thats is enough for now.... I gotta eat something


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## captain_shrapnel (Sep 10, 2004)

If this ws mentioned, I apologize...
When calculating the power draw from your amp do not forget amp efficiency. The modern D class amps can achieve close to 90% efficiency, but I would bet you have an AB class amp. The efficiency of these amps are around 50-60%, so go ahead and double the input requirements for current. 2400 watts out, @ 50% efficiency is 4800 watts in. Divide by 12 volts (keeping the math simple here)= ~400 amps. Start looking at welding cable for a better price on 2/0 gauge.


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## sr20dem0n (Mar 19, 2003)

dundee said:


> sr20dem0n, thats hilarious youre an EE. I was struggling trying to expand guasian surfaces so I used the mini capicator idea. The only thing I hate about my job (and I LOVE my job) is explaining EE concepts to the bossman. So I've gotten used to relating it to Engines, PCs or whatever.



hehe, I can't exactly relate since I'm still in school, and since I'm an engineer pretty much everyone I talk to is as well (no time to mingle with those people who actually have lives), so they know what I'm saying. Every once in a while though a friend from back home will ask me what a hp/lp filter is and what it does, what the "phase" dial means, what is "frequency response", what does 18dB/oct mean, what's a dB, what's an RTA and why did I waste $400 on one.....etc. I gave up trying to actually explain things because 5-10 minutes later they would be staring at me like I was speaking swahili and I'd have to resort to the usual "that doesn't matter", "set it at 80", or "are you sure you want to know?" kind of response.


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## dundee (May 11, 2002)

captain_shrapnel, you are correct sir! Thats way those damn things get so hot, especially the cheap ones. Lets review my notes from Power Electronics with Dr. Ngo ... Just Kidding I'm eating.. :givebeer:


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## dundee (May 11, 2002)

sr20dem0n,

I'm still in school as well but only 2 classes a semester right now because I work full time as well. I go to University of Florida. How about you?


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## jenns240 (May 17, 2004)

dundee said:


> Trust me the capacitor is going to solve the dimming light problem...


a 3 farad cap didnt solve my dimming light problem, and now that im going to be running 3 amps (probably next spring because i dont have the funds to finish my setup) i think im probably going to go with an HO alternator hopefully without needing a second battery. i needed 2 4ga wires for 1 amp, so im also going to upgrade to 0ga. unless someone has another suggestion???


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## sr20dem0n (Mar 19, 2003)

dundee said:


> sr20dem0n,
> 
> I'm still in school as well but only 2 classes a semester right now because I work full time as well. I go to University of Florida. How about you?



Trinity University in San Antonio, TX

17-18 hours every sem just to get out in 4 years....sucks, but it should be worth it


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## captain_shrapnel (Sep 10, 2004)

dundee said:


> captain_shrapnel, you are correct sir! Thats way those damn things get so hot, especially the cheap ones. Lets review my notes from Power Electronics with Dr. Ngo ... Just Kidding I'm eating.. :givebeer:


Yeah, I don't have my EE yet (4th semester of school), but I have been a sound engineer since I was ~15. That should count for something :cheers:


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## Bumpin (Feb 18, 2003)

captain_shrapnel said:


> If this ws mentioned, I apologize...
> When calculating the power draw from your amp do not forget amp efficiency. The modern D class amps can achieve close to 90% efficiency, but I would bet you have an AB class amp. The efficiency of these amps are around 50-60%, so go ahead and double the input requirements for current. 2400 watts out, @ 50% efficiency is 4800 watts in. Divide by 12 volts (keeping the math simple here)= ~400 amps. Start looking at welding cable for a better price on 2/0 gauge.


No it's a class D amp. I'm not THAT lost when it comes to systems. I just needed a little advice on this power supply question.




jenns240 said:


> a 3 farad cap didnt solve my dimming light problem, and now that im going to be running 3 amps (probably next spring because i dont have the funds to finish my setup) i think im probably going to go with an HO alternator hopefully without needing a second battery. i needed 2 4ga wires for 1 amp, so im also going to upgrade to 0ga. unless someone has another suggestion???


Yeah my amp takes 2 4ga power and grounds as well. Did you change your 3 ground connections for less resistance like these guys are saying? Because if you did and you used a 3 farad cap and it still didn't help, then I know to go with something else.


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## sr20dem0n (Mar 19, 2003)

Just so you know Bumpin, I had some pretty bad dimming issues before, I upgraded the big 3 and it fixed everything. I'm still running on the stock alt and stock batt and have no dimming problems. My system now is over twice as big (2200rms total) and I still have no problems, but then again I also listen to my music quieter than I used to.


There are many many more people who have had the same experience with the big 3 on the various audio forums I'm on. For all of them, the big 3 either helped or completely fixed their dimming problems. For $10-15 you can't go wrong, it sure beats the hell out of any other electrical system upgrades as far as effectiveness for the dollar goes.


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## Bumpin (Feb 18, 2003)

Okay cool. I know i'm going to sound like an idiot for this question, but where are the Big 3 located? I'd rather change and fix those before anything else. And do I just change the connection, or the whole wire?


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## sr20dem0n (Mar 19, 2003)

alt + to batt +, batt - to chassis, engine block to chassis

Just find the stock cable in these locations and add your own next to them, don't remove the stock cable, more wire [in parallel] is never a bad thing. I would use 4awg for the alt and engine block connections (your alt can't supply more than ~80 amps so there's no point in going larger, unless you get a HO alt), and up to 0awg for the batt to chassis (it can supply hundreds of amps if it needs to, using larger wire here won't hurt if you have it available).


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## Bumpin (Feb 18, 2003)

Cool. Thanks for all your help guys. I learned ALOT in this thread. LoL


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## dundee (May 11, 2002)

Also when you do this ground the engine block & battery at the same point on the chassis. This will elliminate any possible "ground loop" problems.


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## dundee (May 11, 2002)

jenns240 said:


> a 3 farad cap didnt solve my dimming light problem, and now that im going to be running 3 amps (probably next spring because i dont have the funds to finish my setup) i think im probably going to go with an HO alternator hopefully without needing a second battery. i needed 2 4ga wires for 1 amp, so im also going to upgrade to 0ga. unless someone has another suggestion???


I reviewed your cardomain site. You have A LOT of extra electronics. If you have not done the "big 3" these guys talk about, do so. Other than that you can try messing with larger capacitors or placing another in parallel. Although with that amount of electronics you definately pushing the limits of the stock alternator. At some point you'll probably be looking into a high output alternator.

To answer your question about a single 0 gauge vs. dual 4 gauge lets do some math. The amount of current wire can carry is proprotional to the cross sectional area.

The radius of 0 gauge is 4.126mm. Area is PI*(4.126)^2 = 53.488 mm^2
The radius of 4 gauge is 2.595mm. Area is PI*(2.595)^2 = 21.149 mm^2

But your asking for dual 4ga so multiply by two. 21.149*2 = 42.298 mm^2

your answer is the single 0ga can carry more current than the dual 4ga.


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## jenns240 (May 17, 2004)

dundee said:


> I reviewed your cardomain site. You have A LOT of extra electronics. If you have not done the "big 3" these guys talk about, do so. Other than that you can try messing with larger capacitors or placing another in parallel. Although with that amount of electronics you definately pushing the limits of the stock alternator. At some point you'll probably be looking into a high output alternator.
> 
> To answer your question about a single 0 gauge vs. dual 4 gauge lets do some math. The amount of current wire can carry is proprotional to the cross sectional area.
> 
> ...


i havent upgraded the big 3 yet, the only reason i went with the cap first was because it was free and i heard it would help my dimming light problem and now that im going to be running the 3 amps im going to do the big 3 and get an HO alt. how many amps do you think the new alt should be like 100 or 160? max im looking to spend on an alt is around $270. 

when i decided to go with the optima yellow top it was because i went through 3 batts in 1 month, they were completely drained and wouldnt hold a charge worth a damn. i literally couldnt leave the radio playing for 10 seconds before my car wouldnt be able to start again. do you think with the HO alt that ill need a second battery? 

and since i needed 2 4ga wires for 1 amp do i now need 2 0ga wires for both my bigger amps? i think a single 4ga will be fine for my small amp which is around 300watts RMS (for my components).

i was thinking about getting a cap as well but it will only be for the shiny factor. just to have something that looks nice to sit in the middle of my box.

sorry for all the questions i just want to do it right the first time and get a rough estimate as to what im going to be spedning and not spend money on something i dont need right now and end up spending more to fix it later.


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## sr20dem0n (Mar 19, 2003)

When you have 2 cables in parallel, the resulting size/resistance is roughly equivalent to that of a single cable 3 sizes larger. So 2 4awg is about the same as a single 1awg. Since 0awg is bigger than 1awg, it will carry more current with a smaller voltage drop than a pair of 4awg can. And no you don't need 2 0awg, you would just want a distrobution block similar to this one:
http://www.darvex.com/miva/merchant.mvc?Screen=PROD&Product_Code=SF4MDPT&Product_Count=1

That one has 4 outputs, if you were certain that you weren't going to add any amps in the future then you could go with something like this instead:
http://www.darvex.com/miva/merchant.mvc?Screen=PROD&Product_Code=SF2MDPT&Product_Count=1


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## dundee (May 11, 2002)

Give me the model numbers of the you currently have and the one you are adding.


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## jenns240 (May 17, 2004)

dundee said:


> Give me the model numbers of the you currently have and the one you are adding.


as of now i have 2 crossifre vr2000d amps and a vr602


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## jenns240 (May 17, 2004)

sr20dem0n said:


> When you have 2 cables in parallel, the resulting size/resistance is roughly equivalent to that of a single cable 3 sizes larger. So 2 4awg is about the same as a single 1awg. Since 0awg is bigger than 1awg, it will carry more current with a smaller voltage drop than a pair of 4awg can. And no you don't need 2 0awg, you would just want a distrobution block similar to this one:
> http://www.darvex.com/miva/merchant.mvc?Screen=PROD&Product_Code=SF4MDPT&Product_Count=1
> 
> That one has 4 outputs, if you were certain that you weren't going to add any amps in the future then you could go with something like this instead:
> http://www.darvex.com/miva/merchant.mvc?Screen=PROD&Product_Code=SF2MDPT&Product_Count=1


i forgot about using a distro block. i have 3 laying around but i might buy a new one because im not sure about how many outputs they each have. im going to have to dig them out of my basement to check.


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## sr20dem0n (Mar 19, 2003)

If you're splitting a 0awg to 4awg then make sure you use a fused distro (either that or make sure your main fuse by the batt is smaller than ~120 amps). If one of those 4awg grounds out for some reason, it has to blow the huge fuse in the 0awg before power will be cut. If the fuse in the 0awg is so big that it's not able to do that you could have some major problems on your hands.


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## jenns240 (May 17, 2004)

sr20dem0n said:


> If you're splitting a 0awg to 4awg then make sure you use a fused distro (either that or make sure your main fuse by the batt is smaller than ~120 amps). If one of those 4awg grounds out for some reason, it has to blow the huge fuse in the 0awg before power will be cut. If the fuse in the 0awg is so big that it's not able to do that you could have some major problems on your hands.


ill check that out once i find them. ill look for them when i get out of class tonight.

thanks for all the help.

Jenn


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## dundee (May 11, 2002)

sr20dem0n said:


> When you have 2 cables in parallel, the resulting size/resistance is roughly equivalent to that of a single cable 3 sizes larger. So 2 4awg is about the same as a single 1awg. Since 0awg is bigger than 1awg, it will carry more current with a smaller voltage drop than a pair of 4awg can.


I like your style man... I checked your math too  (42.298/PI)^(1/2) = 3.669mm. The radius of a 1ga is 3.674mm. Nice!


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## dundee (May 11, 2002)

jenns240,

The 0awg as your main power then use your old 4awg to run to the distro block. I would place a large capacitor on the input of each of those mono block amps. You can get HO alternators for a reasonable price from ebay.... 180amp ga16 alternator for ~$250 IRC. You definately want to use a smaller fuse at first on the connection with the battery.... if it blows under normal use you can get a slightly bigger one.... and so on...


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## Bumpin (Feb 18, 2003)

sr20dem0n said:


> When you have 2 cables in parallel, the resulting size/resistance is roughly equivalent to that of a single cable 3 sizes larger. So 2 4awg is about the same as a single 1awg. Since 0awg is bigger than 1awg, it will carry more current with a smaller voltage drop than a pair of 4awg can. And no you don't need 2 0awg, you would just want a distrobution block similar to this one:
> http://www.darvex.com/miva/merchant.mvc?Screen=PROD&Product_Code=SF4MDPT&Product_Count=1
> 
> That one has 4 outputs, if you were certain that you weren't going to add any amps in the future then you could go with something like this instead:
> http://www.darvex.com/miva/merchant.mvc?Screen=PROD&Product_Code=SF2MDPT&Product_Count=1



That first distro block you posted, the one with the 4 outs, that will make 1 0awg into 4 4awg right? I'm about to order it and I want to make sure.


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## sr20dem0n (Mar 19, 2003)

yes, it can do a maximum of 2 4awg and 1 0awg in, and 4 4awg out. If you only want to use the 0awg input that's fine, then you'll have a single 0awg to 4 4awg distro.


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