I was wondering if you have a capacitor, will it eventually die becuase it only stores electrons. Also, the amount of farads it has,like the more it has the more power it will stores or the quicker it will give the power to the amp? I am thinking I will need one, I am running a 150RMS amp, and a 283RMS amplifiers also a red top altima battery. I do not want to kill my alternator so any advice will be appreciated, thanks.

Mooney

 

a cap won't save your alternator, just invest in the battery and you will be fine. no need for a cap with only 433 rms.

 

I know a cap won't save my battery but if the amplifiers take too much power from the battery then the alternator will be recharging the battery at the same time and it will put alot of stress on the alternator. Correct me if I'm wrong.

How much RMS would call for a cap?

P.S. Thanks for the quick reply.

Mooney

 

i wouldnt get one regardless of how much wattage im running. the alternator is going to be stressed regardless of having a cap or not, if you really felt the need for a cap i'd wait till around 2000+ watts, im running 790 rms and i dont use one

 

A capacitor is only really need for 1000w+ systems. It really just stiffens the current being fed to the amp for when those loooow bass hits come around. Just think of it as an extra battery. Except you can't crank your car with it...

I wouldn't even think about it if you are less than 500w. Waste of money and itll put even more strain on your alternator. Since it is connected in parallel with your battery, the alty is trying to charge it just as fast as the battery.

Just addin my .02 to the post

drew

 

It may keep your lights from dimming, however it probably won't make your amps work or sound any better.

CM.

 

Let's clarify something.

#1: A capacitor is simply a specialized battery. It charges and discharges exponetially faster than a conventional battery, even gel cells. It is designed to help the amp that's connected to it to see a constant amount of voltage. During higher demands for voltage, i.e. bass notes, the amp draws that additional current directly from the cap vs the car's regular battery. Since it can charge and discharge in milliseconds, it helps both the amp and sound.

#2: A capacitor will NOT do anything towards helping or impeding an alternator any more than adding an amp to a new car. It is simply an inline specialized battery.

#3: You don't have enough power to make a difference during those voltage transients to warrant a capacitor. The rule of thumb is somewhere between 500-1000 watts RMS before you would benefit from one.

 

It will help the dimming, true.

I will help your amp by not letting it starve for voltage when it needs it to produce the voltage heavy notes. If the amp starves it will begin to overheat, among other things. If the amp is not starved for voltage, it can work in it's intended range and then it's up to the design of the amp to take over and either sound good or not.

So technically, it does help both ways. Is it audible? Most of the time it's not. Where you'll notice it is when you are tuning it and don't have to go crazy on the adjustments (if using a good amp).

 

Listen to these guys. I have a little over 1000 watts RMS and have not had any problems without a capacitor.

 

a capacitor is nothing like a battery. although for the purpose of explanation i guess it can be. typically, a capacitor is at best a band aid fix for a different problem. i would never suggest a capacitor for anything but an all out competition setup (and then it should be in the 50-100 farad range) when you are only doing burps.

 

Not trying to start anything, but that's Bullsh*t!!! By DEFINITION, a capacitor in DC ACTS AS A BATTERY!!! I will send you a copy of the page in my electronics book if you don't believe me.

drew

 

all a cap does is stabilize voltage drops- voltage still drops w/ a cap , just not as dramatically- thus your alternator still suffers

Anyone running over 1000rms is pulling ~ 240 amps or more out of a 105/130pk amp alternator, so those single farads barely tickle the system- North of 3-5 farad is where they may actually do their purpose efficiently-

Xstatic Batcaps are the real deal.....discharge of a cap with the reserve capacity characteristics of a battery-reason why competitors use them, there are many street applications as well-
www.batcap.net

 

heres their brief description....

Quote:
What is a BATCAP©?
A conventional battery, as we all know has a positive and negative terminal. The chemical reaction within creates
a flow of electrons, causing an electronic device (in this case an amplifier) to work. The stiffening capacitor is similar
to a battery in that it stores a charge. The fundamental difference is it cannot create electrons. It can only store and
supply (discharge) them upon demand. The advantage with a capacitor is that it discharges in one twenty thousandth
of a second, unlike a battery that does in one second. The battery therefore cannot discharge fast enough to effectively
supply the amplifier and this is the reason for "power sags."

WAKE UP! Don't fall asleep just yet, we're getting to the exciting part!

The XSTATIC BATCAP© is simply a battery that can discharge just a s quickly as a capacitor. Therefore, you have a
constant supply of electrons that will discharge at lightning speed. This puts less strain on your stock alternator and battery.
It also recharges faster than a conventional battery since the internal resistance is low. How about the install? Well I'm sure
you can find a place to put this 2.5lb. baby and his 5lb. big brother. Don't let the size fool you though. These BATCAP's
can crank your car, and you can bet we put that to the test!

 

They hold the voltage more constant thus giving you more power. (I had a whole long thing typed up but i accidently hit the back button and lost it all)

 

Thanks for the help on the cap. All the information was awsome. I have a question for fuses. I am running a 283RMS amp, not sure of peak, its an Infinity 7520a. I think I am going to run a 60amp fuse, would that be enough or should I go with the 80ap? I can get a pack of 4 30, 40, 50 and 60amp fuses for $2.00, but not the 80amp fuses. I know 30amp won't be enough, or should I go 90amp fuses? Please help me out, thanks.

Mooney

 

Quick google yielded Infinity 7520a

Remember, with fuses, if you go too high, your amp or wires will probably burn up before the high rated fuse blows. Looks like 30A to me.

Have fun!

drew

 

it acts like a battery. that is significantly different than being a battery. if you have the electronics book, look up the differences; they are significant.

as for the fuses, you should be fine with a 40A fuse for that infinity amp.

 

As for the fuses, it comes with a 4 gauge wiring kit. It has an 80amp fuse, the one closest to the battery. Should I be okay with running that size fuse there?

Mooney

 

You're splitting hairs now.

If you call being able to PRODUCE it's own power as the ONLY definition for a battery, then technically you would be correct. Since that's not the ONLY definition or purpose of a battery, then you are not correct.

A cap is very much like a battery except it doesn't produce it's own juice and it doesn't store as much as a conventional battery. That's it. It does however charge and discharge in exponentially shorter times than a conventional battery therefore allowing the amp to see a more constant flow of power. It is a "one hit wonder". It does nothing else. It does have some residual effects as mentioned above, but 99% of it's whole entire existency is based on the premise that it will store a little amount of energy (measured in farads) and will discharge it as needed (when the music hits harder or shifts) thereby TRYING to keep the amp seeing 12V+ all the time even during hard music.

Explain how YOU think that a cap is NOTHING like a battery.

 

Hey, finally someone who has some intelligence!!!
This is one example of how this board gets so misinformed on things. All because of s like this one...

And JMooney5115 would you please read my post about the fuse size. Thank you.

I'm one of the FEW that doesn't post FALSE information. If I don't know about something, I won't post, simple as that. Something more people on this forum should try doing.

Also, JMooney5115, try doing some research by yourself. You MIGHT learn something! www.the12volt.com can get your feet wet with electronics. Also www.howstuffworks.com is great too for everything else!

Ok I'm coming down from my now.

drew

 

OK, but a Cap is still not a battery...there are similarites, though.

1..a battery will always have the same V out (assuming it is healthy), a cap will try and maintain any voltage applied to it 16V, 14.4V, etc.

2..a battery will naturally recover from being discharged...cap won't

Therefore, a battery is a true voltage and current source, a cap is more like a storage tank and will supply current (quite rapidly) to maintain the source voltage. Hence stiffening.

 

Again, you're splitting very minute hairs. YES, a cap is NOT a battery by definition, BUT it is much LIKE one in effect. I believe most of us have used the word LIKE rather than IS, therefore we should be given a little latitude. Remember, we are describing a capacitor in very simplistic terms so as to not confuse people. If we get down to brass tax, we could probably unsurface all kinds of info that would probably not give most people ANY info because of it's complexity. How would that help this discussion?

We're beating a dead horse now since it seems there's a lot of misconceptions about capacitors and I'm afraid people will start to get confused.

We should probably stick to answering direct questions rather than having ****ing contests about logistics. Agree?

 

My vote is for a sticky telling everyone that the 1F cap that the salesman at Best Buy is trying to sell you won't do **** for you and is better used as a paperweight.

 

My lights do not dim with my capacitor.

 

What is Electricity?

 

I have a quick questions about caps. Are all brands pretty much the same or are certain ones better to get than others?

 

you don't need a cap in this case...

even i don't use a cap and ive got an 1800d amp on my 15" xxx

 

good god guys calm down.... this thread didn't need to go this long.

A cap stores power.

It the amps are drawing more power than supplies yeah your headlights will dim and the alternator will have be strained....... get a capacitor to help out with those large surges of power. That in turn takes a load off the alternator.

Simple as that guys. Caps don't have to cost a bunch of money. Check on ebay there are a ton for cheap. You don't need a digintal read out or anything like that so don't worry about those.

 

yo brother, it's people like yourself that cause boards like this to be full of useless, incorrect information. a cap is nothing like a battery. a battery produces electricity through chemical reactions. a capacitor stores electrons in an electric field. what electronics book are you reading from? lol...apparently my electronics engineering book "microelectronic circuits" is not up to par lol. are you an engineering student or a technician student? from your rambling, you seem to be a technician student. you should sit back and take notes from me and MaximaDan. a cap can only maintain the voltage if the alternator can keep it at a steady level, which it usualy can't. as soon as your amp takes current from your cap, you know that your electrical system is lacking. ideally you would have a large enough alternator so that all the cap would do is stabilize AC ripple current.

 

Yo yo patna!!! (I'm following your eloquent lead here) You may wanna check your facts before you spout off at the mouth and make yourself look silly.

I'm far from a "student". I'm probably old enough to be your father, patna. I've been buying, competing, and installing stereo equipment while you were still attached to the cord. So before you go trying to insult someone you don't know anything about, you may wanna put to use some of mom and dad's school money to do a little research. You sound like a very knowledgeable magazine racer. You can keep your nose stuck in your "engineering book" and I'll just keep giving out my "useless" facts on this board which I've been a contributing member of way before you ever thought about having a Maxima. Again, do some research before you start crap with people you don't know.

With that said, Let me point out the mistakes in your "facts" you read out of context in your precious book.

#1: Mr. I read it from my pretty new book so I now know it all.....since you know so much.....where does the a car's battery generate it's "electrons" from? What "chemical reaction"? Quick, go find that in your books index and come back to "enlighten" all of us morons. Are you referring to the acids reaction to the lead plates inside? What about batteries that DON'T have ACID or PLATES? Do THOSE NOT produce "electrons"? Haven't gotten to that chapter in your class yet? Maybe you should ask your professor to help you out there.

#2: Describe an "electric field"? Show me where that is on a stereo's capacitor? Can't? That's probably because a stereo capacitor uses a semi solid media to store it's charge until it discharges. Electric fields are usually created around things like magnets. Even by your own definition, a capacitor CREATES no electricity by itself, right? So how can capacitors create a "magnetic field"? Capacitors have no magnet like qualities. I suppose you're gonna argue that too now, huh?

#3: ME rambling? What the heck do you call this?: "a cap can only maintain the voltage if the alternator can keep it at a steady level, which it usualy can't. as soon as your amp takes current from your cap, you know that your electrical system is lacking."......Say whaaaa????? You don't even know what YOU said there and YOU wrote it. Explain what in the world you're trying to say here. Maybe when you get a little further along in your "engineering" studies you'll get a chance to use an oscilloscope. When you do you can see for yourself that the alternators output is totally different than that coming out of a stiffening capacitor. So, "steady level" has nothing to do in the description of an alternator. BTW, what is "lacking"?

#4: As someone else, including Dan agreed with this, pointed out.....this is not rocket science. YOU may wanna make it out to be, but it really isn't. It's actually rather simple. YOU and a couple of others wanna split microscopic hairs about what it IS and what it ISN'T, all the while ignoring the fact that all of us are using words such as "LIKE" rather than "IS". Get it yet? NO? Let me break it down into simpler terms, since I know you (unlike me) haven't got your 4yr degree quite yet, a capacitor is LIKE (look up the word LIKE in one of your English books and see if it's anything close to the word IS...) a battery in that it stores energy until you need it LIKE a battery. It is also LIKE a battery in that its designed to be charged and discharged numerous times, known as "cycles" (go ahead look it up in your "engineering" book). A capacitor helps the car's electrical system by absorbing some of the initial demand, otherwise picked up by the battery and the alternator, during demanding amp voltage draws. So in essence, the capacitor, since it's installed in-line with the battery, serves as a type of initial BATTERY from which the amp draws power when it needs it.....hmmmm, kinda like the actual definition of the car's battery......hmmmm, I wonder why people would describe them as being LIKE a battery then, huh?



I'm usually not a jerk like this, but I'll make an exception when someone tries to disrespectfully talk down to me like I'm some kind of newbie. I'll be happy to post pictures of MY install and list of equipment as a "resume" to clearly show you what I allegedly don't know. Wanna compare stereo equipment? You should think about things like that before you jump in and start insulting me or anyone else. I don't mind someone disagreeing with me, but if you start disrespecting me I can certainly dish it right back out. If you want to continue this childish playground game with me, I invite you to PM me all you want. Right now, we're serving no purpose to those that want to learn something new or make up their mind if to use a capacitor in their car. You wanna pull your book out and talk over people's heads in an attempt to sound intelligent, go for it. It only serves to confuse people and give them incorrect info. Everyone that has first hand knowledge about capacitors have already chimed in and said the initial poster doesn't really need one. All this other BS is both far off topic and unnecessary.

I'm certain this thread has now pretty much served it's purpose and should be locked.

 

Here is very simplistic and easy to understand terms describing a capacitor (thanks to whomever put up the "how it works" link). See if you can find the similarities between what some of us have been saying:

"In a way, a capacitor is like a battery. Although they work in completely different ways, capacitors and batteries both store electrical energy. If you have read How Batteries Work, then you know that a battery has two terminals. Inside the battery, chemical reactions produce electrons on one terminal and absorb electrons at the other terminal." .....

"A capacitor is a much simpler device, and it cannot produce new electrons -- it only stores them.".....

"Like a battery, a capacitor has two terminals. Inside the capacitor, the terminals connect to two metal plates separated by a dielectric. The dielectric can be air, paper, plastic or anything else that does not conduct electricity and keeps the plates from touching each other...."

"Once it's charged, the capacitor has the same voltage as the battery..."

"Like a Water Tower
One way to visualize the action of a capacitor is to imagine it as a water tower hooked to a pipe. A water tower "stores" water pressure -- when the water system pumps produce more water than a town needs, the excess is stored in the water tower. Then, at times of high demand, the excess water flows out of the tower to keep the pressure up. A capacitor stores electrons in the same way, and can then release them later."


Funny how if it's nothing LIKE a battery, why is it that everytime you look up any information about a capacitor the word battery pops up everywhere in the description?????? Again, LIKE is far from IS. That to me is splitting hairs since we are trying to describe something to someone in simple terms so they can begin to understand what it is. Why not describe it using something that most people can relate to and already understand? hmmm, kinda like a BATTERY?

 

I don't mean to me a ****, but I kinda take that personal. I was Mechinal engineer for 2 years at Bama and honestly couldn't pass Thermo II or Dynamics. I'm a pretty small guy that had a hell of a lot more hands on knoledge than any engineer in my classes. Don't hate people because you think they can't calculate as good as you because you're an "engineer". You probably havne't even graduated yet. yeah I know being an engineering student gives you something to be cocky about, but just relax man. OOOOOH wow you're in EE Circuits and can finally read the difference between a capacitor and batter.

Hooking up a stereo isn't rocket science so don't make people feel stupid.

 

Guys we're hear to help people out.

 

wildmanal and jamiecbr900, the above post was the one that offended me. This guy comes on here and bashes a "newbie" because he states that a cap is not a battery...they aren't. If they are than please tell me what size batteries you need to build a low pass filter.

I understand using a battery as a comparison, but that is it. They are not equal.

 

Okay children, a cap is nothing like a battery. But that is irrelevent to the topic. For the amount of power that the amps can draw - in the car that we all drive a cap is not needed. Less than 1000 watts I shouldn't think that a maxima owner would need a cap unless the amps are really cheap and or loosely regulated. If that is the case a cap may be useful to prevent lights from dimming, but likely won't make a difference in the sound of the music. A more useful solution would be a better amp. Does this means caps don't have a useful purpose, nope! They are great, used properly.

 

oh i feel bad now. im a newbie. =( sorry man, i do know quite a bit about this kinda stuff. been working on cars for about 10 years now, doing electronics for about 6 of those. and have studied the theory behind all this, so you can say that you know this and that, but really it is you spewing false information.

 

Alright I guess I'm just an idiot... Kill me now please...

 

The one that should've offended anyone was the one where Mr. "Student" comes in all high and mighty thinking that because he read it in his shiny new book at school he now knows everything.

I didn't post the post you reference above either. I never said I had an issue with you at all. You didn't disrespect me although you disagreed with me. I don't have a problem with that. Young bucks who spout off at the mouth w/o even knowing who they're talking to is a different story. Again, that wasn't you though.

I was trying to explain to the original poster, who is obviously confused as to what a capacitor does, in simple terms so he could begin to understand. If someone else has a better other than "like a battery", then go for it. So far the only other explanations given have been far to technical to help someone with limited exposure. That's just MY opinion though. Yall can take that with a grain of salt.

 

1) My parents do not pay for my education.

2) ALL BATTERIES produce electricity from chemical reactions, it does not have to be from a lead/acid chemical reaction.

3)I assume you never took a calculus level physics course in electricity and magnetism. The charge on a capacitor is stored in an electric field. Whenever there is a voltage present between 2 conductors, an electric field is formed. Capcitors do not create a magnetic field, where the hell did you come up with that? Inductors store energy in a magnetic field. What you need is a course in Maxwell's equations my friend. You are totally lost here.

4) I have an oscilloscope. a 30MHz one to be exact. I have no idea what i am talking about? Is that because you don't understand a word of what i said? lol. if the voltage on the capacitor drops below a certain level say 13.8 volts, it is because the electrical system is being taxed beyond its capabilities. DUH!

5) your quote: So in essence, the capacitor, since it's installed in-line with the battery, serves as a type of initial BATTERY from which the amp draws power when it needs it.....hmmmm, kinda like the actual definition of the car's battery......hmmmm, I wonder why people would describe them as being LIKE a battery then, huh?

A capacitor is not in-line with a battery chief, it's parallel to it, If a cap was in-line with a battery, no current would flow through it. A cap cannot be like a battery if it has none of the characterisitcs of a battery (maybe it has one similar characterisitcs, but that's all)

6) obviously your 4 year degree is not in electrical engineering since you don't even know the basic physics behind a capcitor.



Dielectrics, insulating materials placed between the plates of a capacitor, cause the electric field inside the capacitor to be reduced for the same amount of charge on the plates. This is because the molecules of the dielectric material get polarized in the field, and they align themselves in a way that sets up another field inside the dielectric opposite to the field from the capacitor plates. The dielectric constant is the ratio of the electric field without the dielectric to the field with the dielectric.


SO GUY, JUST BECAUSE YOU DON'T UNDERSTAND CAPACITORS DOESN'T MEAN YOU CAN BELITTLE ME AND TELL ME MY INFORMATION IS WRONG. YOU NEED TO TAKE SOME PHYSICS CLASSES TO LEARN ABOUT FIELDS (BOTH ELECTRIC AND MAGNETIC). I WILL NOT SIT HERE AND EXPLAIN ELECTRICITY AND MAGNETISM TO YOU.

AND BIG ****IN DEAL YOU INSTALL STEREO EQUIPMENT, PLENTY OF 14 YEAR OLDS CAN DO THAT AS WELL. THAT DOESN'T MEAN YOU UNDERSTAND THE PHYSICS BEHIND WHAT YOU ARE INSTALLING.



one other thing. why is it that people always bash engineers because they know the theory? you people wouldn't have car stereos and amps if it weren't for us. the technicians wouldn't have jobs if we werent around. yea we do a lot of design on paper and on computers, but WE are the ones who test the designs before they are ever mass produced. i'm sick of all the bull****. when an engineer corrects you, JUST ****IN LISTEN instead of trying to defend yourself and digging a deeper hole for urself.

The reason why i was negative about all of it is because people like you (with incorrect info), are always so proud of ur answers even when you are wrong. **** THE BULL****.

 

theres a lot of engineers on these forums. i am also. aerospace though.