battery question

lol...250 amp fuse... Must look reaaaal pretty... Anyways, in any case, your amp will never suck out 240 amps. In order for that to happen, I beleive, the gain needs to be up 100% and the volume 100%, and the beat needs to have a huge peak. It won't draw a constant 240 amps (unless your playing helicopter soundtracks at full volume, or something along those lines) I still feel, though, that you will need a H/O or dual alternator setup down the road, especially if you're competing.~wayland

haemphyst wrote: Please see the above notice I just typed. I think if YOU want to run 1600A through a #4, I don't want you ANYWHERE near my house or car wiring... A wire is NOT a transformer. A #4 cable is SAFE at no more than 150A, whether it is carrying 12 or 12000 volts. It is true, he needs bigger wire, considering the current capacity he is trying to apply, but the math remains the same. .. .. .. Speaking of somebody who really does not understand... An amplifier output is a high VOLTAGE output, this means you can use a smaller gauge wire, and still observe acceptable losses. When you raise the voltage, Ohm's law says you MUST lower the current, if you are maintaining the same amount of POWER. If you ONLY raised the voltage, without lowering the current you would be increasing the power... Something that cannot be done. This would be equivalent to negative losses. What I mean by this is (and let's assume a 100% efficient amplifier) If you have a 100A drain at 12v, this is 1200w, right? Well across 4 ohms, 12 volts is only 36 watts, a FAR cry from 1200... to get 1200 watts OUT, you must raise the voltage to 69 volts. If we were to raise the voltage to 69 volts, but KEEP the current at 100A, our (only) 100 percent efficient amplifier would be outputting 6900w into a 4 ohm load - it can't happen, it would be a 690% efficient amplifier... As Ohm's law says, the current MUST go down, if the voltage goes up. In this case, down to 17.4A, perfectly capable of being passed through a #12 speaker wire safely...

I used the same exact reasonoing that you just used to come to my conclusions. 4guage wire is rated at either 240v or 600v, I can't remember which. I'll just assume 240v. 240v is 20 times more then 12v. So, at 240v 240w = 1 amp. At 12v 12w = 1 amp. I might be getting a little bit confused here. Does the voltage at which the current is run not matter? I mean, can you still only draw the same number of amps at 12v as you can at 240v?

First off, to Poormanq45, current is current is current... it does not matter WHAT the voltage is, as long as you remain within the safe thermal operating limits of the insulation. The heat in a wire is DIRECTLY correlated to the amount of current being pulled through it. The voltage drop at that current is the heat lost in the wire. Example: If you are pulling 100 amps through a wire (forget the voltage referenced to ground or neutral - 12v, 240v, 600v), and your voltage drop is 1 volt (end to end drop), that wire is dissapating 100 watts. It does not matter whether it is 15000 volts or 15 volts. The voltage drop TIMES the CURRENT is all you are worried about. Wire is not rated in voltage. Insulation is. When you look at THHN wire at your local Home Depot, and you see 600v pasted all over that wire, all that is saying to you is that the insulation protecting the wire is rated at 600 volts. I think this is where your confusion is happening. Also, if you are thinking that a #4 is rated at 80A, you would be correct. The National Electrical Code states this is the maximum rated current interruping device for this size wire, BUT it also SHOULD tell you that it is ONLY for the current carryinig conductor in the circuit, IN CONDUIT. The neutral in North America and the ground are NOT considered current carrying conductors. 12 volts DOES not listen to the NEC. Secondly: Here is the answer to ace customs... Lets break this up alittle bit, shall we?

ace customs wrote: My setup right now it a four guage wite wire a 250 amp fuse on it going to a distribution block that goes to two Audiobahn D class 1200 rms amps.

First off, you ARE looking at causing a fire if anything ever happens to the insulation on that 4 gauge. A #4 should NEVER be fused higher than 150A. In fact, you are even overfused for a #2, which should be fused at 225A.

ace customs wrote: I have them bridged together creating 2400 rms at 2ohms. The orion 12 is dual 4 ohm with bridges to 2 ohm. It is in a ported box right now with the correct amount of air space and port size. I also have three 1 farad capacitors.

Yes the amplifiers can be bridged, but the speaker does not bridge, it is a load. If the voice coils are wired in parallel, you are presenting a 2 ohm load to the amplifiers, INTO which the amplifiers are bridged. You are probably correct in your statement of a two ohm load bridged. External bridging of an amplifier DOES NOT cause them to behave the same as internal bridging. Internal bridging inverts one channel, causing twice the voltage across the load, thus quadrupling the power. In MOST cases, an external bridge simply allows the outputs of BOTH amplifiers to be placed across the load in parallel, thus keeping the voltage and current the same into one half the load - thus DOUBLING the power. I cannot speak to the external bridging methods of the Audiobohms, as I have never used them.

ace customs wrote: I already have one more orion h2 12 that i am going to put in there with a dual ported box and two more d class audiobahn 1200 rms amps. I understand that my alternator will only put out so much power not sure on exact figure but i assume it is around 110 amps. Without adding a new alternator can this system be ran in this car with another battery or huge capacitor. Will the alternator be strong enough to keep the system charged.

No. Period. You are asking for trouble and/or early electrical system failure, if you insist on taxing this electrical system much further than you already are. If ALL you ever had was 2400 watts (shyah, right) of digital power, you will already be pulling as much as 2400/.8=3000 watts IN, divided by 14.4 volts is 208 amps. You are so far beyond your current capabilities as it is, I can't even begin to imagine the issues you will be seeing. Later on in your post, you mention no wanting to void your warranty? It'll be voided by electical system failure for sure...

ace customs wrote: It will only be played very loudly for demos and comps. I am going to upgrade to 0 guage whether it will truely give off that much power or not. It sounds like to me everyone has a different opinion on how much watts 4 guage will hold. I am planing on using a 1 input 4 ouput distribution block. 0 guage in and 4 guage out after the connection to the second battery in the trunk. It sounds like I need an HO alternator anyways even with my current system. I dont have problems with power drainage though like on previous cars. The lights dont dim when the bass hits.

Probably not... Your amps are getting NOWHERE NEAR the current required to produce all of the power they are "capable" of, simply due to the resistance in your power cable from the battery to the system...

ace customs wrote: Does anyone know where I can get an HO alternator for my car.

I have had good luck with www.4alterstart.com, but apparently, some others have not had QUITE the good luck I have had... Perhaps there are others willing to have an input.

ace customs wrote: You are right about caps only being good for a couple of thumps. The first three or four thumps are the loudest then the power slowly decreases. I notices that haemphyst said that I dont need another alternator and then sedate says that I do. It makes sense to me to get one, but I still have like 2 years of waranty and like 30000miles so I didnt want to add an alternator if I dont have to.

I have re-read the posts I have made, and I cannot see anywhere I said you did not need a larger alternator. The reason you are experiencin what you are experiencing is because you simply DO NOT HAVE ENOUGH ALTERNATOR... End of story. You MUST buy a larger alternator right now, let alone doubling the damand you are thinking about placing on you existing electrical system. I have said this before, and I will probably end up saying it again - caps are NOT completely useless, but they DO NOT DO ANYTHING TO FIX A LOW CURRETN/LOW VOLTAGE CONDITION. This is what you have right now.

ace customs wrote: It would be easy to just pop an extra battery out of the trunk. You all sound like you know what you are talking about but you all have different ways of backing up your opinions. Oh and it sounds like to me senate that even if I have an HO alternator it wont produce enough amps to power this system. Because yeah your right it is 240 amps for just the too amps thats 480 for four. I know it wont realistically be that much but even if it was 300 amps there isnt an HO alternator big enough to produce this much power. Sound do I need to split the current amps one on each sub and leave out the other two amps all together.

You WILL need a big alternator, possibly a dual alternator setup for a system like this. You are absolutely correct in saying there is no (single) alternator available to provide this kind of current. If you think I am wrong, or that anybody else is more right, please check out a 12volt.com VERY often quoted website here: www.bcae1.com, and do some research for yourself. There are people here that know more than I do, but on all of the information I have posted, I feel EXTREMELY correct... thirdly:

wayland1985 wrote: lol...250 amp fuse... Must look reaaaal pretty...

I bet it does, but you are off base... Read on.

wayland1985 wrote: Anyways, in any case, your amp will never suck out 240 amps. In order for that to happen, I beleive, the gain needs to be up 100% and the volume 100%, and the beat needs to have a huge peak. It won't draw a constant 240 amps (unless your playing helicopter soundtracks at full volume, or something along those lines)

Whether it pulls 250A or not, that IS NOT what the primary fuse is there for... The primary fuse is to protect the primary wire, and you NEVER fuse it for more than the wire is rated for. Please see this chart, if you do not understand this...It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

cool thanks for the advice. I am sure of the bridging of the amps. I ran the sub in parallel and it has a 2 ohm load. Sorry if the wording isnt right, but I know how to bridge amps and I know how to run subs in certain ohms. I just dont know a lot about high power systems. We dont sell alot of them and this is the biggest system or most powerful system I have every installed as you can probably tell. The reason I had a 250amp fuse was because I was going to upgrade to 0 guage if I only kept the one sub with the two amp setup. I dont ever turn the system up right now because of the lack of power. I have 0 guage from the battery to the fuse holder and from there to the trunk is 4 guage which is about to be changed. Does anyone know where I can get a Jaguar x type HO alternator. There are no parts for this car. I recently dropped the car with H&R springs and there is not a camber kit available for my car. (that makes alot of sense). So I am afraid there isnt a company that makes these. I may have to have my rebuilt. Now the final question. If I get a new alternator and extra battery will this give enough power to a least run the two digital amps and one more A/B high current amp that is the same size, or should I just leave that out and stick with trying to get the most power out of the two digital amps with the one twelve.Ace Customs

ace customs wrote: The reason I had a 250amp fuse was because I was going to upgrade to 0 guage if I only kept the one sub with the two amp setup. I dont ever turn the system up right now because of the lack of power. I have 0 guage from the battery to the fuse holder and from there to the trunk is 4 guage which is about to be changed.

That's fine... I, too am a fan of forward thinking, but not at the expense of safety. GET THE 250A FUSE OUT OF THERE!!! That, or change the wire out NOW... You are worried about voiding your warranty, I am worried about you BURNING YOUR CAR TO THE GROUND! To hell with the warranty.

ace customs wrote: Does anyone know where I can get a Jaguar x type HO alternator. [EDITED FOR SPACE] I may have to have my rebuilt. Now the final question. If I get a new alternator and extra battery will this give enough power to a least run the two digital amps and one more A/B high current amp that is the same size, or should I just leave that out and stick with trying to get the most power out of the two digital amps with the one twelve.

I gave you a place - www.4alterstart.com Have you listened to anything anybody has said? Really all that is going to happen, is you are going to have to cram as big an alternator as you can under the hood, THEN build your system UP TO A SAFE OPERATING RANGE, BASED ON THAT ALTERNATOR. If you are going to a dual alternator setup, same thing applies, based on the amount of current the alternators can provide, in total. If you INSIST on building your system FIRST, than you will have to locate an alternator that will run your system with at LEAST 50A MORE CURRENT CAPABILITY, for all of your accessories. Batteries and caps mean nothing, ALL of your power ultimately comes from your alternator. START THERE! Let me say it again - START WITH YOUR ALTERNATOR, but you need to do the math first!!!It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Thanks for the explaination. I now understand it, but I'm having a problem with something still. WHy is it that on a 120v circuit you can transmit ~9600watts through a 4guage wire, but when put in a car on a 12v circuit it can only transmit ~960watts? I'm just not understanding that. Is a watt not equal a watt?

Yes I listen and I checked the site. They do not offer one for an x type, unless they can rebuild my current one.Ace Customs

Ace: First off, in case you can't tell, haemphyst and I are the only ones who have posted to this thread that have any idea what we're talking about. Take my word for it, your system will thank you. Everything we said is in absolute total agreement. 1)We both think you need a HO alternator and you are probably going to have to get one manufactured or rewound for you. This is *not* going to be cheap for a car like yours. Still, I couldn't imagine it costing more than a single one of those amps. Oh wait, Audiobahn.. Okay two of those amps. 2)If you ONLY want the system to be able to play for a *few seconds* at a strech, at demo's and comp's and what not, you could get by with a pair (or even 3) of deep cycles in parallel. Go back and read what haemphyst said about this, you can wire them directly to each other, or through a relay as I suggested. 2 or 3 Yellow tops in parallel *will*, at least for a few moments, run all that crap. 3)Good! Upgrade the wiring and haemphyst is right about being wayyy overfused. 4)Back the Alternator Question - If you can even double the output of your alternator.. to say a round 200-amps, this alternator tied to a pair of deep cycles and some capacitance will be able to keep the two amps you have happy. I bet even another A/B. If you stick with your stock alt, I'd again, go with a pair of deep cycles in parallel and cross your fingers. If you only need a few moments here and there, you ought be okay with that kinda of reserve capacity. Then again having your subs cut out your while you try to demo a car has *got* to be embarassing.. Doubling your current though? 5 amps? Again, with the LARGEST alternator you can buy and then you need to mate that to LARGEST rack of deep cycles you can buy. Just doing some quick math it looks like your peak draw will be in the 500+ amp range. 5)My Recommendation: Leave out the extra amps. haemphyst said it best "No. Period." Get your HO alternator and see if you can get the rest of that warranty pro-rated off the car loan or whatever. Trying to worry about the freakin factory warranty and shoeing in a system that draws like 500 amps are DEFINATELY MUTUALLY EXCLUSIVE goals. After you get your HO Alt, add a pair of Optima Yellows in parallel, + to +, - to -, each + post fused within 18 inches of the battery. Go ahead and wire up your caps while your at it. Go ahead and add your A/B amp. 6)My Recommendation if you just CANNOT get an HO Alt: Drop the 2nd 1200D, add that A/B (you wearn't going to run ur highs off the <gasp> .. deck?) and, again, two yellows and a cap. You ought be able to run that 12 off a single amp and 1200 watts will motivate *anything* 2000 watts RMS or no. Keep us posted Ace. "I'm finished!" - Daniel Plainview

Poormanq45 wrote: Thanks for the explaination. I now understand it, but I'm having a problem with something still. WHy is it that on a 120v circuit you can transmit ~9600watts through a 4guage wire, but when put in a car on a 12v circuit it can only transmit ~960watts? I'm just not understanding that. Is a watt not equal a watt?

Because of the CURRENT. The wire, in this case a number 4, can safely carry 150A, again, whether the voltage is 12 or 120 volts. (Distance DOES come into play here, also, but lets just say it's a 20 foot cable). Lets just say we are using the NEC (#4 wire, circit breaker protected at 80A - forget the voltage) for all of our safe current carrying capabilities... If you are pulling 80A at 120 volts, this is 9600 watts, but the SAME 80A safe current carrying capacity at 12 volts is 960 watts. The watts (amount of power carried) is smaller in the lower voltage circuit BECAUSE of the lower voltage. V*A=W. Simple as that... Is that better now?It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."