# Capacitor Myth



## sniper5431

Could we have something in here explaining this issue?


----------



## boom_squid_2

what issue?


----------



## Oliver

capacitor | eHow Search



> What Is an Electrical Capacitor?
> 
> By *Paul Dohrman*, eHow Contributor
> 
> An electrical capacitor is a device on which a charge collects. The usual shape is two metallic plates parallel to each other but touching only two terminal ends of a circuit wire, not each other. Electrons flow from one plate through the electrical circuit and to the other plate, due to the electromotive force of a battery or other source of energy. The charges on each plate are equal and opposite in polarity. The plates are therefore attractive.
> 
> * Storage of Energy*
> 
> 1. Because the battery, or some other source of electromotive force, displaces electrons from one plate of the capacitor to another, energy is built up and stored in the capacitor. The circuit wires could be removed, and the charge difference between the plates would remain. The energy stored in the capacitor equals the energy required to keep the two plates apart, opposing their Coulomb attraction (an attraction due to their electrical charge). If the plates were not held in place, they would attract each other, make contact, and discharge.
> 
> * Discharge*
> 
> 2. A voltage can be discharged by placing a piece of metal between the two plates, making contact with both. The excess electrons of the negatively charged plate would then rush over to the other plate, thus removing the excess negative charge on one plate, and the excess positive charge on the other.
> 
> *Charge Accumulation*
> 
> 3. Charge accumulation is not absolute. That is, it does not stop until the capacitor is detached from the circuit. This is because getting the capacitor's voltage (due to the accumulation of charge) any proportion closer to the final voltage takes a finite amount of time. The voltage building up between the plates therefore has an asymptotic shape, when graphed against time.
> 
> In Alternating Currents
> 
> 4. When the power source supplies an alternating current, the capacitor alternates charge polarity along with the circuit. Electrons falling onto one plate are then pulled off and sent to the other plate, and so on, each time the power source switches polarity.
> 
> Use in Electronic Products
> 
> 5. Capacitors can be used for pulsed power, upon discharge of the charge on the capacitor plates. Pulsed power is useful when sudden bursts of energy are required, e.g. in a laser, or a linear accelerator.
> 
> Capacitors, after charging, can be used like a second battery, when the primary battery is being recharged. This is particularly important when vital memory is involved.
> 
> _ Capacitors can be used to smooth out fluctuations in power supply inside electronic equipment.
> 
> Capacitors are also used as noise filters, radio tuners, in amplifiers, and in numerous other devices._


----------



## ChrisB

A capacitor is NOT a substitute for an inadequate electrical system. It takes power (current) to make power (watts) and most of the smaller capacitors will drain faster than one can blink their eyes. 

The larger capacitors, 40 farads or more, have been alleged to help in some situations. Unfortunately, at that pricing point, one would be better off purchasing a second "new technology" fast discharge battery.


----------



## sniper5431

+1 ChrisB. Figured this would be a good subject for this section.

Rich


----------



## i_theo

Replacing cheaper capacitor with higher grade capacitor (the same value) not always perform better .. cause pasif designer already make research with the old one to make match design.


----------



## XC-C30

^^

n00b answer :laugh:


----------



## i_theo

XC-C30 said:


> ^^
> 
> n00b answer :laugh:


 .. Yes Sister .. lost my old user id.


----------



## FartinInTheTub

I use an Alumapro Carbon 15 farad and I will swear by it. i had light dimming issues and once added these symptoms went away completely. Not to mention that this does my power and ground distribution nicely. I do agree however that most caps are a bandaid. I used to have a Stinger 1 farad capacitor and it wasn't very effective.


----------



## Candisa

So you replaced a weak bandaid by a strong one?

If you "need" a 15Farad capacitor to prevent the lights from dimming, you *need* a better battery and alternator!


----------



## XC-C30

^^

Why I'm your #1 fan Honey Like your style!!


----------



## Oliver

One possible use >>>>



> Energy storage
> 
> A capacitor can store electric energy.
> In car audio systems, large capacitors store energy for the amplifier to use on demand. Also for a flash tube a capacitor is used to hold the high voltage.
> [edit] Pulsed power and weapons
> 
> Groups of large, specially constructed, low-inductance high-voltage capacitors (capacitor banks) are used to supply huge pulses of current for many pulsed power applications. These include electromagnetic forming, Marx generators, pulsed lasers (especially TEA lasers), pulse forming networks, radar, fusion research, and particle accelerators.
> 
> Large capacitor banks (reservoir) are used as energy sources for the exploding-bridgewire detonators or slapper detonators in nuclear weapons and other specialty weapons. Experimental work is under way using banks of capacitors as power sources for electromagnetic armour and electromagnetic railguns and coilguns.
> 
> Power conditioning
> A 10,000 microfarad capacitor in a TRM-800 amplifier
> 
> Reservoir capacitors are used in power supplies where they smooth the output of a full or half wave rectifier. They can also be used in charge pump circuits as the energy storage element in the generation of higher voltages than the input voltage.
> 
> Capacitors are connected in parallel with the power circuits of most electronic devices and larger systems (such as factories) to shunt away and conceal current fluctuations from the primary power source to provide a "clean" power supply for signal or control circuits. Audio equipment, for example, uses several capacitors in this way, to shunt away power line hum before it gets into the signal circuitry. The capacitors act as a local reserve for the DC power source, and bypass AC currents from the power supply. This is used in car audio applications, when a stiffening capacitor compensates for the inductance and resistance of the leads to the lead-acid car battery.


_I've looked for articles on capacitors used as energy draining devices , couldn't find any ._

*Can one of you enter one in WIKI ....*


----------



## FartinInTheTub

Candisa said:


> So you replaced a weak bandaid by a strong one?
> 
> If you "need" a 15Farad capacitor to prevent the lights from dimming, you *need* a better battery and alternator!


I have an Optima yellow top and stock BMW alternator. I'm an Industrial/Commercial electrician with 20+ years experience... I know how power is stored and discharged. The Alumapro isn't your average "bandaid". You say I "need" an extra battery and alternator? thats your opinion. My solution worked perfectly for me. Thanks for your opinion.


----------



## Candisa

If you know how power is stored and discharged, you also know that a capacitor only catches up the peaks in the current-demand (but most amps already have capacitors inside to do this), but raises the constant current-demand.

The only difference is: without a capacitor, you're kicking your alternator and battery untill it finally dies and with a capacitor, you're letting it die a slow and painfull death.

I'm pretty sure your alternator will die one day (probably taking the battery with it) and I'd recommend you to get an upgraded one + a better battery (an Optima Yellow Top isn't exactly the finest quality, it's just well known...) and then try out the install without the 15F capacitor in between. 
I'm sure the lights won't dim anymore and as long as the battery is fine or you replace it in time, and you don't add power to the system, the upgraded alternator will last untill the carbon-brushes are worn out.

Isabelle


----------



## FartinInTheTub

Candisa said:


> If you know how power is stored and discharged, you also know that a capacitor only catches up the peaks in the current-demand (but most amps already have capacitors inside to do this), but raises the constant current-demand.
> 
> The only difference is: without a capacitor, you're kicking your alternator and battery untill it finally dies and with a capacitor, you're letting it die a slow and painfull death.
> 
> I'm pretty sure your alternator will die one day (probably taking the battery with it) and I'd recommend you to get an upgraded one + a better battery (an Optima Yellow Top isn't exactly the finest quality, it's just well known...) and then try out the install without the 15F capacitor in between.
> I'm sure the lights won't dim anymore and as long as the battery is fine or you replace it in time, and you don't add power to the system, the upgraded alternator will last untill the carbon-brushes are worn out.
> 
> Isabelle


Yes... I understand that a capacitor "catches up" the peaks. and yes it does raise the constant current demand. But if your new constant current demand is within acceptable/safe limits your alternator and battery will be fine. I've considered a second battery but the real estate taken up is not something I want to part with. I appreciate your advice, thank you


----------



## bose301s

FartinInTheTub said:


> I have an Optima yellow top and stock BMW alternator. I'm an Industrial/Commercial electrician with 20+ years experience... I know how power is stored and discharged. The Alumapro isn't your average "bandaid". You say I "need" an extra battery and alternator? thats your opinion. My solution worked perfectly for me. Thanks for your opinion.


Sorry, being an electrician does not mean you know all that much about electricity, it means you know how to wire things and not get yourself killed.


----------



## Sarthos

Electrician or electrical engineer? The fact you're an electrician doesn't mean you know that much about electricity, my uncle was a master electrician for 40 years, doesn't mean he could tell you everything about a car's electrical system.


----------



## FartinInTheTub

Sarthos said:


> Electrician or electrical engineer? The fact you're an electrician doesn't mean you know that much about electricity, my uncle was a master electrician for 40 years, doesn't mean he could tell you everything about a car's electrical system.


I am a UNION electrician and proud of it. trained in not only AC but DC.. as well as complex motor controls, relays, etc,... I know what i'm doing. i don't need to defend what I know to 24 and 25 year old kids. I was trying to be civil and polite to you by simply responding. try doing the same.

ps.. I also have a degree in electrical engineering from The university of California, Berkeley but I chose to work in the field since sitting behind a desk doing CAD drawings bores the **** out of me. I am also an Electrical contractor. thanks again for your opinions... I will consider them when doing my install.


----------



## bose301s

FartinInTheTub said:


> I am a UNION electrician and proud of it. trained in not only AC but DC.. as well as complex motor controls, relays, etc,... I know what i'm doing. i don't need to defend what I know to 24 and 25 year old kids. I was trying to be civil and polite to you by simply responding. try doing the same.
> 
> ps.. I also have a degree in electrical engineering from The university of California, Berkeley but I chose to work in the field since sitting behind a desk doing CAD drawings bores the **** out of me. I am also an Electrical contractor. thanks again for your opinions... I will consider them when doing my install.


Ok, then you do understand electricity pretty well then. I am an EE as well and had an internship at an electric utility for a summer and while the line crews knew what they were doing installing stuff and how not to get injured they really had no clue about electricity other than that.


----------



## FartinInTheTub

bose301s said:


> Ok, then you do understand electricity pretty well then. I am an EE as well and had an internship at an electric utility for a summer and while the line crews knew what they were doing installing stuff and how not to get injured they really had no clue about electricity other than that.


Working with an electrical utility is a very good start when getting into EE. that's great! I to interned with 3 different engineering firms while attending school at berkeley. I loved it but I truly love hands on work. Designing plans and doing Code Calcs are not my idea of fun. I like the dirty work. take care man!


----------



## bose301s

FartinInTheTub said:


> Working with an electrical utility is a very good start when getting into EE. that's great! I to interned with 3 different engineering firms while attending school at berkeley. I loved it but I truly love hands on work. Designing plans and doing Code Calcs are not my idea of fun. I like the dirty work. take care man!


I actually got into the semi conductor industry, lol. I am doing more of a materials related job, in school I took electronics and semiconductor classes and well as electronic materials classes vs. power classes. I work for Cree making LEDs, I like it, it's the kind of stuff I wanted to do.


----------



## FartinInTheTub

bose301s said:


> I actually got into the semi conductor industry, lol. I am doing more of a materials related job, in school I took electronics and semiconductor classes and well as electronic materials classes vs. power classes. I work for Cree making LEDs, I like it, it's the kind of stuff I wanted to do.


Wow! That's cool how you found your niche. LEDs are the future of lighting. You're picking the right field to be involved in. very impressive.


----------



## Oliver

FartinInTheTub, very impressive !!

My father-in-law was doing the programming of machines,{EPROMS}, at a company that made automotive firewalls and such , [ subcontractor], when he passed.

Worked for Edison Electric for years ,{ his home was a centennial }, sponsored by Edison.

He had numerous accomplishments and Titles in his time.

His barn was loaded with a variety of electrical parts leftover from his business.

He was District D-2 governor for The Lions Club.

He seemed to think of a capacitor as being beneficial in certain applications , based on his limited experience !


----------



## stream

Candisa said:


> an Optima Yellow Top isn't exactly the finest quality, it's just well known..


More info please.


----------



## Candisa

FartinInTheTub said:


> i don't need to defend what I know to 24 and 25 year old kids. I was trying to be civil and polite to you by simply responding. try doing the same.


I hope this wasn't an answer to me, since I've tried to be civil and polite myself while giving my opinion about that 15F capacitorbank you're using...
But I'm 25 myself and if you don't mind, I'd rather be called a woman than a kid. 

I'm into (car-)audio since I was 15-16, did sound quality competitions in 2005 with great results, studied (literaly translated "Industrial Science", which includes quite some both AC as DC electricity and electronics... So I also know what I'm talking about. 

I have a happy relationship with my gf (probably next year: wife), own a mostly renovated house of our own, don't need to depend on mommy and daddy or anybody else if we need something... so I'd appreciate it if you wouldn't call all <25 year olds kids... 

Isabelle


----------



## Candisa

stream said:


> More info please.


It's just as simple as I said it: everybody knows Optima and I bet caraudio-dealers get a nice quote on them, so a lot of people use them and everybody thinks it's because they're the best...
Fact is an Optima Yellow Top becomes nothing more than chemical waste after you discharged it completely a few times, just like an ordinary liquid acid battery...

There are plenty of batteries on the market that are not only cheaper, but also withstand discharging completely better, discharge slower when not in use, have a lower internal resistance causing a better and faster maximum peak-current delivery...

We have here an Exide Maxxima Deep Cycle for example. Costs a bit less than a comparable Optima, but won't die after a couple complete discharges.
I've had this battery standing around for almost 3 years after the previous project, without any maintenance-charging, just standing there...
3 years later, I needed it, so I brought it to the guy that always fixes my car to hang it on his professional battery charger for a few days and asked him to do measurements and tests on it since it wasn't used for so long...
The result: it still performed better than the specs said!!!

Isabelle


----------



## FAUEE

Capacitors have some great uses.

Capacitors are NOT for letting you put in a "bigger system". Capacitors do not give you more energy. Capacitors will not give you more "watts". 

A Capacitor is great for allowing a 4 channel amp to have instant access to all the power it needs, and for cleaning up the power generated by your alternator. Capacitors are also nice for helping to negate light dimming from using your windows, etc. while listening to your music. A big capacitor can be a good thing, and when used as a SUPPLEMENT, its a valuable piece of equipment.

If your amp pulls 200A and your car only has a 110A alternator, a cap will not help you. In fact, it might make your problem worse. If your car has an ailing alternator, and you have recently started to get light dimming from it, a capacitor will not help you and will help kill your alternator faster.

As an aside, I'm an EE here too. Wish i could get a nice internship at a power utility, I'd love to get a job in a power plant. Nice stable and high paying work there.

I couldn't imagine going through EE school to just be an electrician. The money's just not in the same league, and it's a whole lot of time spent for no reason. I can understand wanting to be more hands on (I'm the same way), but man, I just don't think I could make that same decision. EE is 5 years pretty much country wide now, that's a lot of time to get into something that's not what you graduated in.


----------



## FartinInTheTub

FAUEE said:


> Capacitors have some great uses.
> 
> Capacitors are NOT for letting you put in a "bigger system". Capacitors do not give you more energy. Capacitors will not give you more "watts".
> 
> A Capacitor is great for allowing a 4 channel amp to have instant access to all the power it needs, and for cleaning up the power generated by your alternator. Capacitors are also nice for helping to negate light dimming from using your windows, etc. while listening to your music. A big capacitor can be a good thing, and when used as a SUPPLEMENT, its a valuable piece of equipment.
> 
> If your amp pulls 200A and your car only has a 110A alternator, a cap will not help you. In fact, it might make your problem worse. If your car has an ailing alternator, and you have recently started to get light dimming from it, a capacitor will not help you and will help kill your alternator faster.
> 
> As an aside, I'm an EE here too. Wish i could get a nice internship at a power utility, I'd love to get a job in a power plant. Nice stable and high paying work there.
> 
> I couldn't imagine going through EE school to just be an electrician. The money's just not in the same league, and it's a whole lot of time spent for no reason. I can understand wanting to be more hands on (I'm the same way), but man, I just don't think I could make that same decision. EE is 5 years pretty much country wide now, that's a lot of time to get into something that's not what you graduated in.



Actually the money is there if you are motivated. My Union Wireman make an average of $75k/yr. As a contractor/owner I pull in after overhead/expenses between 200k and 250k. I could NEVER make that working strictly as an EE. And with my degree and experience I don't have to hire EEs to design for me. It's a win win for me and I get to truly enjoy my work and get out in the dirt with my boys.

PS:

"Just an Electrician" isn't a very nice thing to say. The IBEW Union apprenticeship is 5 years of school and 8000 hrs of OJT just to qualify to take your Journeyman exam. I did the entire 5 years of apprenticeship as well as my time at Berkeley. IBEW Union wireman are some of the best trained Commercial/Industrial Electricians in the world. 300+ apply every yr just for the opportunity to enter the apprenticeship... maybe 20-25 a year are let in. So being "Just and electrician" is an understatement in my opinion.


----------



## FAUEE

FartinInTheTub said:


> Actually the money is there if you are motivated. My Union Wireman make an average of $75k/yr. As a contractor/owner I pull in after overhead/expenses between 200k and 250k. I could NEVER make that working strictly as an EE. And with my degree and experience I don't have to hire EEs to design for me. It's a win win for me and I get to truly enjoy my work and get out in the dirt with my boys.


Ah see that makes sense there, if you can combine being an EE and an electrician, there's definitely money there. Vertical monopolies are a beautiful thing.

A guy in my classes was a union electrician, but he got downsized with the economy the way it is. He's going to be an EE now, he gets all his school and living expenses paid for by unemployment insurance. Downside for him is he's "middle aged" now, so a lot of companies don't want to take him on as a new hire. I think his old company is likely to take him in as an EE though.


----------



## Oliver

FAUEE said:


> Capacitors have some great uses.
> *
> "Capacitors are NOT for letting you put in a "bigger system"*. _Capacitors do not give you more energy. Capacitors will not give you more "watts". _
> 
> A Capacitor is great for allowing a 4 channel amp to have instant access to all the power it needs, and for cleaning up the power generated by your alternator. Capacitors are also nice for helping to negate light dimming from using your windows, etc. while listening to your music. A big capacitor can be a good thing, and when *used as a SUPPLEMENT, its a valuable piece of equipment.*
> 
> If your amp pulls 200A and your car only has a 110A alternator, a cap will not help you. In fact, it might make your problem worse. If your car has an ailing alternator, and you have recently started to get light dimming from it, a capacitor will not help you and will help kill your alternator faster.
> 
> As an aside, I'm an EE here too. Wish i could get a nice internship at a power utility, I'd love to get a job in a power plant. Nice stable and high paying work there.
> 
> I couldn't imagine going through EE school to just be an electrician. The money's just not in the same league, and it's a whole lot of time spent for no reason. I can understand wanting to be more hands on (I'm the same way), but man, I just don't think I could make that same decision. EE is 5 years pretty much country wide now, that's a lot of time to get into something that's not what you graduated in.


*Thank You FAUEE !*

*"Capacitor Myth Busted"
*


----------



## FartinInTheTub

Yes! Nice explination Oliver!


----------



## sonikaccord

How about a 3000 farad capacitor??
Maxwell 3000 Farad Ultracapacitor Supercapacitor, Solar - eBay (item 370416238952 end time Jan-30-11 17:19:37 PST)
6 of these in series


----------



## FAUEE

sonikaccord said:


> How about a 3000 farad capacitor??
> Maxwell 3000 Farad Ultracapacitor Supercapacitor, Solar - eBay (item 370416238952 end time Jan-30-11 17:19:37 PST)
> 6 of these in series


I'm gonna replace my battery with these. 

Actually, I'm poking fun now, but honestly 15 years ago people would have poked fun at people wanting to use LEDs for lighting. Nobody's laughing now, it's actually cutting edge and a very real future technology.


----------



## danssoslow

Someone explain to me how a capacitor increases the load on a circuit. How does a capacitor use energy? I've always thought of them as an electrical accumulator, only a storage device.


----------



## sonikaccord

danssoslow said:


> Someone explain to me how a capacitor increases the load on a circuit. How does a capacitor use energy? I've always thought of them as an electrical accumulator, only a storage device.


It doesn't theoretically.

It doesn't pass DC current.
If you analyze it with AC current, it affects the impedence of the circuit but doesn't use energy, just stores it.


----------



## danssoslow

If it doesn't use energy, then how does it raise the current demand?


----------



## sonikaccord

danssoslow said:


> If it doesn't use energy, then how does it raise the current demand?


It can't by itself. 

When a capacitor is discharged, it basically just waits until the demand goes down and then it recharges itself when everything is equalized. It resists changes in voltage.


----------



## danssoslow

Now see, that's what I figure. Others don't seem to believe that is so.


----------



## Sarthos

You know, I've always thought this is weird. Why do they have 1 farad capacitors that are about the size of that thing or smaller, that thing which claims 3000 farads at that size, but most 1 farad capacitors in cars are the size for a thermos? Just because people think the bigger they are the better they must be?


----------



## bose301s

FAUEE said:


> I'm gonna replace my battery with these.
> 
> Actually, I'm poking fun now, but honestly 15 years ago people would have poked fun at people wanting to use LEDs for lighting. Nobody's laughing now, it's actually cutting edge and a very real future technology.


Yes, LEDs have a very bright future


----------



## sonikaccord

Sarthos said:


> You know, I've always thought this is weird. Why do they have 1 farad capacitors that are about the size of that thing or smaller, that thing which claims 3000 farads at that size, but most 1 farad capacitors in cars are the size for a thermos? Just because people think the bigger they are the better they must be?


It's a double layer capacitor. It's a new ish type of capacitor that packs in more capacitance per area. They call them, supercapacitors (real creative  )

The big 1 farad caps are a bunch of hot air
YouTube - Inside a 2 Farad Car Audio Capacitor--Gucci Mane--Hasta La Vista-- 

Yes, size sells.


----------



## Sarthos

lol. I was actually thinking they would have a tiny 1 farad capacitor inside of it, like the little 1 farad capacitors one might see in a physics class, then just a bunch of padding. I wish I could tell what that stuff is, it looks like just some foam insulation mostly.


----------



## ride2wheels

Oliver said:


> *Thank You FAUEE !*
> 
> *"Capacitor Myth Busted"
> *


I have been debating this question. Thank you for helping in my decision.


----------



## ChrisB

On a positive note about capacitors... In 1997, I had a 1996 Thunderbird with an impossible to solve noise issue. I tried everything I could think of and three different shops tried all sorts of things, but nothing worked. I called a buddy of mine who was out in California in the service and he told me to try a capacitor because it helped a noise issue in his truck. I installed a 1/2 farad capacitor and it filtered out the power line generated noise that no one else could solve.


----------



## Candisa

Caps are indeed great for that. That's exactly why they are used in power supplies: smoothing the power signal.
A capacitor reacts a lot faster than a battery and especially older amps can't handle a seriously soiled power signal on their own, so adding a cap right in front of the amp(s) is the best way to clean the power signal up before it enters the amp.

The only reason why a cap also helps light-dimming issues is because it keeps the voltage as stable as possible, not only when the power coming from the battery/alternator is soiled, but also when an amp pulls the voltage down by asking more current than the load-system can handle.
The problem is a capacitor is actually too fast to do this. It will catch up the peak in the current demand, but it will recharge to 99.999% (a capacitor is never 100% full) as fast as it can, causing probably an even higher current-demand on the load-system and eventually drain itself and the battery, and kill the alternator when you play dynamic music at high volume level for a long time.
A bigger capacitor will only stretch this process.

An extra battery will also try to keep the voltage stable and catch up peaks in the current demand, but will recharge slower, causing less drain on the load-system.
Yes, this will eventually drain the load-system and maybe even kill it too if the extra battery has to catch up every single peak all the time, but that's why you have to start with a strong enough alternator and power wiring!


So:
- A capacitor is great for reducing distortion on the power signal, but NOT for dimming lights, whatever the size of it (smaller capacitors are even better in doing what they're designed for!!!), and now even the most critical people know and understand why!
- The only solution for dimming lights is upgrading power wires, alternator and battery-bank. It isn't called the BIG 3 for nothing!

/thread

Now can somebody make a permanent sticky of this that won't get lost when somebody messes with the forums again?

Isabelle


----------



## danssoslow

Candisa said:


> but it will recharge as fast as it can, causing probably an even higher current-demand on the load-system and eventually drain itself and the battery, and kill the alternator when you play dynamic music at high volume level for a long time.


This is where I have doubts. I do believe a capacitor will only replenish itself as fast as the circuit will allow it to. Just like an accumulator, it can only take what is available. Since it uses no power of its own (except for maybe a little dissipated in the form of heat), it will not consume any energy; therefore not putting any extra load on a circuit.


----------



## bose301s

danssoslow said:


> This is where I have doubts. I do believe a capacitor will only replenish itself as fast as the circuit will allow it to. Just like an accumulator, it can only take what is available. Since it uses no power of its own (except for maybe a little dissipated in the form of heat), it will not consume any energy; therefore not putting any extra load on a circuit.


Incorrect, a capacitor is definitely a fairly lossy device, leave a charged car capacitor sitting for even a minute and the voltage on it will have dropped significantly. This means that to stay at a constant voltage the capacitor will always have a parasitic draw. Also, after a voltage sag the capacitor will try and recharge itself once the voltage is above the voltage the cap dropped to. Everyone should read teh capacitor article on Wikipedia, it is helpful.


----------



## sonikaccord

bose301s said:


> Incorrect, a capacitor is definitely a fairly lossy device, leave a charged car capacitor sitting for even a minute and the voltage on it will have dropped significantly. This means that to stay at a constant voltage the capacitor will always have a parasitic draw. Also, after a voltage sag the capacitor will try and recharge itself once the voltage is above the voltage the cap dropped to. Everyone should read teh capacitor article on Wikipedia, it is helpful.


ESR? There is leakage current that causes it to discharge on it's own but I see no reason why it shouldn't hold a charge for longer than a minute at it's charged voltage. Plus if the voltage is constant in a dc scenario, it acts as infinite resistance and the amp is pulling straight from the alt or battery voltage. 

I agree, the capacitor will always try to match it's charging voltage.

Caps are passive(dumb), how can they cause an extra strain on the electrical system? They can't discharge below the lowest source voltage when it sags which is the same as drawing straight from the battery.


----------



## bose301s

sonikaccord said:


> ESR? There is leakage current that causes it to discharge on it's own but I see no reason why it shouldn't hold a charge for longer than a minute at it's charged voltage. Plus if the voltage is constant in a dc scenario, it acts as infinite resistance and the amp is pulling straight from the alt or battery voltage.
> 
> I agree, the capacitor will always try to match it's charging voltage.
> 
> Caps are passive(dumb), how can they cause an extra strain on the electrical system? They can't discharge below the lowest source voltage when it sags which is the same as drawing straight from the battery.


This is true, but they also need to charge back up after the drop pulling more from the system. I actually had a crappy Scosche .5 farad cap from Wal Mart that I was messing with in a lab at school, it was not from my car or anything, it was from a project we did, but I would charge it up to ~18V just for fun then let it sit, it discharged suprisingly fast just sitting there. Maybe higher quality capacitor are better for this but thats all I had.


----------



## sonikaccord

bose301s said:


> This is true, but they also need to charge back up after the drop pulling more from the system. I actually had a crappy Scosche .5 farad cap from Wal Mart that I was messing with in a lab at school, it was not from my car or anything, it was from a project we did, but I would charge it up to ~18V just for fun then let it sit, it discharged suprisingly fast just sitting there. Maybe higher quality capacitor are better for this but thats all I had.


Sounds like an interesting experiment. 
How many cases does a capacitor work in? I've seen all this talk about caps don't work but none about a capacitor fixed this.


----------



## FAUEE

Caps work depending on what you want to fix. You can't use a screwdriver to use a nail, and you can't use a hammer to put in a screw. Different tools for different jobs.

The problem with a cap is not only that its fairly lossy, it also will charge and discharge more. Think of it this way, say you have no cap and your amp pulls enough power to drop you down to 12V from 14.4V, Your lights will dim but after the bass hit its over. If you have a cap, you may only drop to 12.2V or something, but then after the hit the electrical system must recharge the cap up to 14.4V, causing extra strain. Now imagine you're doing this on a weakened alternator that is already too small to power your system. The extra strain of having to charge and recharge the cap, as well as power everything will cause your alternator to die a premature death.

Capacitors can be made in different ways, many of the "super caps" are constructed in a different way than your normal caps. The normal caps you see are basically scaled up versions of the ones you would find inside your amps, they're considered to be better for signal transmission, and easier and cheaper to make. Things like the BatCap and the Soundsstream and other big caps are constructed in a different way that allows them to hold more energy.


----------



## sniper5431

Excellent job all! This explanation of a highly debated subject is perfect for this section. It is also why this forum is so valuable to all. 

Thanks everyone who contributed.

Rich


----------



## ride2wheels

I love the information you guys put out. Its been very helpful


----------



## HCCA

> Think of it this way, say you have no cap and your amp pulls enough power to drop you down to 12V from 14.4V, Your lights will dim but after the bass hit its over. If you have a cap, you may only drop to 12.2V or something, but then after the hit the electrical system must recharge the cap up to 14.4V, causing extra strain.


See, this is what I've always had a problem with. Strain?!?! 

A cap's purpose, since it's inception for car stereo use in the '90's was that it was to be used to cover the bass hit that draws power in "peaks". A cap was NEVER for the purpose of replacing a battery. In Autosound 2000 tech briefs, it was explained that the real, and ONLY purpose was to cover for the bass notes that were a larger demand than the alt/batt could cover(for a brief micro-second). Thus improving dynamics. Now, the REALLLLY important part. A cap will not help you IF you have a 200 amp draw, on a 110 amp alt. It just won't. *AND, it was NEVER meant to!* A cap's purpose (introduced, for CA use, by David Navone), was that it was to cover the bass hits on a system that might draw 120 amps on the bass hit, but draw 90 amps throughout the rest of the musical passage (given the same 110 amp alt)!!!!!!! 

So, if I have a 230 amp HO alt, and 250 amp draw on a bass hit, *but* draw 200 amps the rest of the time. IT CAN HELP (if the cap is of sufficient size for the task)!!! If I have a consistent 280 amp draw on the same charging system, with peaks of 300 a cap WILL NOT HELP!!!!! For a cap to work, it has to have time to recharge for the next bass hit. If the load is forever more than the alt can deliver, it will not charge the cap....*nor a battery, for that matter!!!!!!!!!!! Hence, you will only draw the voltage available from the battery....until it's dead. * Let's drive this point home!!!! If the recommendation by some is to add more batteries, you STILL NEED TIME to charge them, as well!!!!! Can someone tell me HOW you can charge a battery, for God's sake, with the same charging system, that is insufficient to charge a cap?!?!?!!? Gee, let me guess, you can charge the dead batteries on your drive home with the system turned off?!? Or, put them on the charger, overnight, after you've completely drained them?? Because that's what WILL happen when you play ANY, I repeat, ANY system that draws more power than the alt povides, for an extended period of time! 

Steve Mead Designs, uses multiple alternator systems, as a common practice. If your system needs 400 amps of current at peak demand, you SHOULD supply it with the alternator(s) sufficient to carry the load. Running multiple amps demanding 400 amps of current with a 175 amp alt (even accounting for Big 3, multiple batts, whatever...) is STILL not the answer!!! Caps, or not!! 

So, more batteries, instead of a cap, is no answer either....IF, *IF* your answer is that more batteries (instead of cap) is the answer to insufficiant alernator output.


----------



## FAUEE

HCCA said:


> See, this is what I've always had a problem with. Strain?!?!


I agree with the rest of the stuff for the most part, though I would say your numbers might be a bit optimistic. I don't think a normal sized cap will give you the equivalence of 30A larger alternator. It'd have to be one of those "supercaps" of over 10F.

I guess strain isn't the best word though. Modern alternators have the voltage regulator and try to adjust for the current load placed on it. When you place a large load on it for a brief instant, it might not be able to ramp up. But when you are trying to recharge your capacitor in addition to that large load spike, you will overwork your alternator. If the alternator is already on its last legs, it will speed up the process of destruction.

Battery systems without an upgraded alternator are meant to be isolated from the rest of the electrical system and be recharged by alternate means IMO.


----------



## sonikaccord

That's the only reason I see caps being used...

To fill in the delay when alternator realizes it needs to up the output.

The amps power supply has caps that serve the same purpose: To supply power for demanding transients for short periods of time(milliseconds). When you add an external cap, you're really just extending the supply capacitance, right? Either way they both have to be filled so does that mean your amp's caps is straining your electrical too? Or here's a better question, How does an amp's power supply handle transients??

As far as the multiple batteries...I was thinking about that a bit. If the batteries "rest" at 12V give or take some volts, how can adding more 12V batteries stop dimming if your alt can't supply the current? It would be the same as replacing your starting battery with a super extra large battery. Both ways will sag if the alt sags... A cap, however, will rest at charging voltage, 14.4V plus or minus of course and how long it can maintain that voltage depends on the capacitance.


----------



## FAUEE

sonikaccord said:


> That's the only reason I see caps being used...
> 
> To fill in the delay when alternator realizes it needs to up the output.
> 
> The amps power supply has caps that serve the same purpose: To supply power for demanding transients for short periods of time(milliseconds). When you add an external cap, you're really just extending the supply capacitance, right? Either way they both have to be filled so does that mean your amp's caps is straining your electrical too? Or here's a better question, How does an amp's power supply handle transients??
> 
> As far as the multiple batteries...I was thinking about that a bit. If the batteries "rest" at 12V give or take some volts, how can adding more 12V batteries stop dimming if your alt can't supply the current? It would be the same as replacing your starting battery with a super extra large battery. Both ways will sag if the alt sags... A cap, however, will rest at charging voltage, 14.4V plus or minus of course and how long it can maintain that voltage depends on the capacitance.


The caps will be charged to 14.4V, but will likely drop down to 12V pretty quickly. They have an internal voltage loss anyways, plus there's a little bit of electricity used by your car even when its off (in newer cars it might not be that little too). So it will attempt to keep the voltage at 14.4V and discharge down to your battery's resting voltage fairly quickly.

Charging a battery is pretty heavy duty work. Charging a bank of them is a royal pain in the ass. Especially when the alternator is also expected to provide you power to run your system normally.


----------



## Wheres The Butta

I know this is sort of O/T but just wanted to point it out... LEDs are not the "future of lighting," that is just hype. They will play a useful part in lighting schemes, but by no means will they replace all other lighting - it's not possible nor is it desirable. 

I work in the lighting industry.


----------



## HCCA

sonikaccord said:


> That's the only reason I see caps being used...
> 
> To fill in the delay when alternator realizes it needs to up the output.
> 
> The amps power supply has caps that serve the same purpose: To supply power for demanding transients for short periods of time(milliseconds). When you add an external cap, you're really just extending the supply capacitance, right? Either way they both have to be filled so does that mean your amp's caps is straining your electrical too? Or here's a better question, How does an amp's power supply handle transients??
> 
> As far as the multiple batteries...I was thinking about that a bit. If the batteries "rest" at 12V give or take some volts, how can adding more 12V batteries stop dimming if your alt can't supply the current? It would be the same as replacing your starting battery with a super extra large battery. Both ways will sag if the alt sags... A cap, however, will rest at charging voltage, 14.4V plus or minus of course and how long it can maintain that voltage depends on the capacitance.


BINGO!! You got it right! The dip in the brightness of the headligts is the voltage dropping from 14.4, to 12.4 (or thereabouts). When you insert the cap into the circuit, the cap floats at the alts voltage potential. When a bass note causes the lights to dim, it is because there is a power demand, exceeding the alts immediate capability. As stated in AS 2000 tech briefs, you should use _at least_ 1 farad of capacitance for each 1000 watts of amplifier power. Hence, the reason sooooo many think that they do nothing. Sure add a 1 farad cap to a 3000 watt system, and you might not see any improvement. 

I'm planning to add a Stinger SPC 5050 Hybrid cap, to my system. Carbon caps had as much internal resistance as a battery, so not much help there. Electrolytic caps are best, but they could get expensive, and take a lot of fasteners, wiring, and room to get just a few of them in parallel. But, the Stinger Hybrid uses a carbon cap, for large amounts of storage (@ 14.4V), and a large electrolytic cap, in parallel. One 1/0 wire pos; one 1/0 neg. Still very effective, but keeping the cost down. It's said to be enough capacitance for 10K watts. 

On another note, I've heard guys say that caps are voodoo, myth, hype, etc. That they do absolutly nothing. However, they also admit that they will keep your headlights from dimming. So, how is it again, that they do "nothing"? If they stabilize voltage enough that headlights don't dim, they are keeping the system voltage @ 14.4V, right? Don't know abou the rest of you, but my amps owner's manual shows a wide variance in output wattage for 14.4V vs, 12.5V. And, if the 1, 2, 4, 10 farads of capacitance "do nothing" to stabilze system voltage, then those teeny weenie 10K-100k farads of capacitance inside the amp sure can't make a difference! Right?? 
As David Navone put it, you can never have too much capacitance. 

For the commonet that caps have internal resistance? ....and, batteries don't???!?


----------



## dales

good read. lots of debate. i will say this, id rather use a battery(s) and alternator , aswell as wiring that have been upgraded to sustain the electrical draw.


----------



## my6x9s

i own a pair of stinger 25 farad and they accept 1/0awg so i have 50 farad for 3200w
things i noticed from use i originally went from battery bank to cap then to next cap then amp. i personally did no notice any difference at all 
rewired to current set up, wired the caps straight to the battery bank and ran a run straight off the buss bars straight to the amp thats where i noticed the nite vs day difference the snap back / kick to the gut bass hugely different in a good way like it had a extra1/3 more push behind it ... this is my opinion but since im swaping out my system this spring i will retest my thoughts and theory with a termlab we just got one to use so i will let you all know the findings i would right now but shes all tor down for the rebuild... vary good read all


----------



## Mickydoos

FAUEE said:


> you can't use a hammer to put in a screw..


Yes you can! It's why its called an Irish screwdriver


----------



## Oliver

Mickydoos when were you in Eire ?




> By kissing the Blarney Stone at Blarney Castle, it is claimed that one can receive the "Gift of the Gab" (eloquence, or* skill at flattery *or persuasion)


----------



## asawendo

FAUEE said:


> Caps work depending on what you want to fix. You can't use a screwdriver to use a nail, and you can't use a hammer to put in a screw. Different tools for different jobs.
> 
> The problem with a cap is not only that its fairly lossy, it also will charge and discharge more. Think of it this way, say you have no cap and your amp pulls enough power to drop you down to 12V from 14.4V, Your lights will dim but after the bass hit its over. If you have a cap, you may only drop to 12.2V or something, but then after the hit the electrical system must recharge the cap up to 14.4V, causing extra strain. Now imagine you're doing this on a weakened alternator that is already too small to power your system. The extra strain of having to charge and recharge the cap, as well as power everything will cause your alternator to die a premature death.
> 
> Capacitors can be made in different ways, many of the "super caps" are
> constructed in a different way than your normal caps. The normal caps you see are basically scaled up versions of the ones you would find inside your amps, they're considered to be better for signal transmission, and easier and cheaper to make. Things like the BatCap and the Soundsstream and other big caps are
> constructed in a different way that allows them to hold more energy.


Yep this is the situation when your sound system over the limit of your alternator output can give. Bigger caps only worsen the situation. CMIIW.

Best Regards

Wendo


----------



## starboy869

caps should be the last in line for upgrade.\

Upgraded Alt and Battery first and then a low ESR cap. Not a stupid 1fd one either.


----------



## narvarr

HCCA said:


> If the recommendation by some is to add more batteries, you STILL NEED TIME to charge them, as well!!!!! Can someone tell me HOW you can charge a battery, for God's sake, with the same charging system, that is insufficient to charge a cap?!?!?!!? Gee, let me guess, you can charge the dead batteries on your drive home with the system turned off?!? Or, put them on the charger, overnight, after you've completely drained them?? Because that's what WILL happen when you play ANY, I repeat, ANY system that draws more power than the alt povides, for an extended period of time!


While this is true that a battery needs to be recharged, it does not have as big of a draw as a cap due to the fact that it makes it's own energy. Current draw on a system using a cap is going to be higher than a system using multiple batteries. Yes, it is best to upgrade your charging system, but with the price of compact low ESR batteries being where they are, I can't see huge cap being logical.

Sent from my X10i using Tapatalk


----------



## Sarthos

> While this is true that a battery needs to be recharged, it does not have as big of a draw as a cap due to the fact that it makes it's own energy. Current draw on a system using a cap is going to be higher than a system using multiple batteries. Yes, it is best to upgrade your charging system, but with the price of compact low ESR batteries being where they are, I can't see huge cap being logical.


A battery makes its own energy? Please enlighten me on this one, seeing how that sounds to me like we must have achieved that perpetual motion thingy. Batteries store energy but don't make any.


----------



## narvarr

Last time I checked, the chemical reaction between the lead plates and the acid in the battery is what produces energy. 
Check this link "How batteries work"
Sent from my X10i using Tapatalk


----------



## starboy869

if that was the case then there wouldn't be a thing called a battery charger or having an alt in a car.

Batteries only store energy, and doesn't create.


----------



## narvarr

starboy869 said:


> if that was the case then there wouldn't be a thing called a battery charger or having an alt in a car.
> 
> Batteries only store energy, and doesn't create.


Did you click the link? Car batteries do make energy, otherwise it would be called a capacitor. Just like anything else they do have a limit as to how long it lasts. Unlike a cap, they create energy as they are used until all electrons are depleted. Caps store energy only, batteries create energy...but still have limits.


----------



## narvarr

Ok, for all of those who think batteries just store energy and don't create energy...how did they get the charge in a battery before batteries were rechargable?

Sent from my X10i using Tapatalk


----------



## tornaido_3927

^^ A battery does NOT create energy.. It converts chemical energy to electrical energy. Some may view that as it being created, that however is _wrong_.


----------



## narvarr

tornaido_3927 said:


> ^^ A battery does NOT create energy.. It converts chemical energy to electrical energy. Some may view that as it being created, that however is _wrong_.


Correct, thank you for the help. That being said, a battery is going to have a less parasitic draw on a system than a capacitor due to that fact.

Sent from my X10i using Tapatalk


----------



## TrickyRicky

bose301s said:


> Sorry, being an electrician does not mean you know all that much about electricity, it means you know how to wire things and not get yourself killed.


So true.


----------



## starboy869

The law of conservation of energy is an empirical law of physics. It states that the total amount of energy in an isolated system remains constant over time (is said to be conserved over time). *A consequence of this law is that energy can neither be created or destroyed: it can only be transformed from one state to another.* The only thing that can happen to energy in a closed system is that it can change form: for instance chemical energy can become kinetic energy.

http://en.wikipedia.org/wiki/Conservation_of_energy

I did see the link. youtube... haha I rather read my sicence book. 

'Create isn't the word they should've used' more like convert or something.


----------



## narvarr

starboy869 said:


> The law of conservation of energy is an empirical law of physics. It states that the total amount of energy in an isolated system remains constant over time (is said to be conserved over time). *A consequence of this law is that energy can neither be created or destroyed: it can only be transformed from one state to another.* The only thing that can happen to energy in a closed system is that it can change form: for instance chemical energy can become kinetic energy.
> 
> Conservation of energy - Wikipedia, the free encyclopedia
> 
> I did see the link. youtube... haha I rather read my sicence book.
> 
> 'Create isn't the word they should've used' more like convert or something.


I was not trying to get THAT technical with it and go down to the molecular level with this...all I was stating is that a battery does more than just "store energy". Wasn't trying to be funny or anything with the clip either, just trying to prove a point. BTW, that Youtube clip originally came from here: The Science channel


----------



## Sarthos

Except here's the thing. You were wrong both in the literal meaning of it creating energy (which defies the laws of physics) and it adding energy to a system without charging it (which also requires that it defies the laws of physics) A rechargeable battery converts chemical energy to electricity and also converts electricity into chemical energy. When it charges it draws off the capacitor. You don't rely on those electrons to add to your system like a AA battery.


----------



## narvarr

Sarthos said:


> Except here's the thing. You were wrong both in the literal meaning of it creating energy (which defies the laws of physics) and it adding energy to a system without charging it (which also requires that it defies the laws of physics) A rechargeable battery converts chemical energy to electricity and also converts electricity into chemical energy. When it charges it draws off the capacitor. You don't rely on those electrons to add to your system like a AA battery.


I did not say that it didn't need to be charged ANYWHERE in my previous posts. In fact I said the opposite. I realize that there is a chemical reaction that causes this and stated so in my previous posting. But since you are more concerned with winning the argument on a technical level rather than looking at the bigger picture...YOU ARE RIGHT, I AM WRONG. Happy now?

Unsubscribed


----------



## Sarthos

Sorry, just trying to avoid giving someone who comes in here and reads this the idea that you can just add battery after battery and the batteries will provide energy without a proper charging system. Something that many, many people go ahead and try. Ever see someone with half a dozen batteries twenty caps, a stock alternator, and wonder why they have problems?


----------



## sonikaccord

narvarr said:


> I was not trying to get THAT technical with it and go down to the molecular level with this...all I was stating is that a battery does more than just "store energy". Wasn't trying to be funny or anything with the clip either, just trying to prove a point. BTW, that Youtube clip originally came from here: The Science channel


Dang...I thought he found an infinitely self charging battery.

I get what he's saying...
A battery is "creating" the energy that has already been "given" to it, but when it runs out of this "given" energy it can't "create" anymore.

hmmm, sounds like storing energy to me. My question is what more does a battery do than store energy? Do you know what physically happens to a battery as it charges/discharges?


----------



## Sarthos

It boils battery acid, leaks out hydrogen gas, etc. 

Hmm, before dry cell batteries, weren't capacitors used in part due to the fact they can be mounted upside down and sideways and inside cars and everything you can't do with a battery?


----------



## sonikaccord

I don't think so...mainly cause of the capacity (lol pun) is higher for a battery.


----------



## starboy869

Candisa said:


> Caps are indeed great for that. That's exactly why they are used in power supplies: smoothing the power signal.
> A capacitor reacts a lot faster than a battery and especially older amps can't handle a seriously soiled power signal on their own, so adding a cap right in front of the amp(s) is the best way to clean the power signal up before it enters the amp.
> 
> The only reason why a cap also helps light-dimming issues is because it keeps the voltage as stable as possible, not only when the power coming from the battery/alternator is soiled, but also when an amp pulls the voltage down by asking more current than the load-system can handle.
> The problem is a capacitor is actually too fast to do this. It will catch up the peak in the current demand, but it will recharge to 99.999% (a capacitor is never 100% full) as fast as it can, causing probably an even higher current-demand on the load-system and eventually drain itself and the battery, and kill the alternator when you play dynamic music at high volume level for a long time.
> A bigger capacitor will only stretch this process.
> 
> An extra battery will also try to keep the voltage stable and catch up peaks in the current demand, but will recharge slower, causing less drain on the load-system.
> Yes, this will eventually drain the load-system and maybe even kill it too if the extra battery has to catch up every single peak all the time, but that's why you have to start with a strong enough alternator and power wiring!
> 
> 
> So:
> - A capacitor is great for reducing distortion on the power signal, but NOT for dimming lights, whatever the size of it (smaller capacitors are even better in doing what they're designed for!!!), and now even the most critical people know and understand why!
> - The only solution for dimming lights is upgrading power wires, alternator and battery-bank.* It isn't called the BIG 3 for nothing*!
> 
> /thread
> 
> Now can somebody make a permanent sticky of this that won't get lost when somebody messes with the forums again?
> 
> Isabelle


last time i check to the avg person a big three cost $$.

What I've seen a few time that's is funny. 0GA big three upgrade. Stock alt, battery, cheapest of the cheap 8GA wire (or less) going back to a jensen amp. One poor kid paid like $50+ in wire from a shop for the wire also (they saw him coming). I told him for his setup the most you want to see under the hood in his setup is 4GA tops. Also get a low ESR battery like a stinger. I said for $150 I can hook him up with something for his setup. He decided no cause $150 wasn't in his budget, cause he just blew over $50 on a big three upgrade that didn't really help out.


----------



## starboy869

CCA is junk wire to begin with.

0/1 wire with the preformace of 2ga (or less) Then why not just get 2GA copper instead?

Best upgrade you can do is engine block to ground and neg. battery terminal to ground. 
Also if you have junk factory battery terminals ie. honda then it's worth the upgrade. 
After I did this upgrade the noticed my lights didn't dim as much, and the pw when up/down a quicker/smoother. I just used 4GA for my 2000 Civic Si/SiR. 





chris


----------



## starboy869

sonikaccord said:


> How about a 3000 farad capacitor??
> Maxwell 3000 Farad Ultracapacitor Supercapacitor, Solar - eBay (item 370416238952 end time Jan-30-11 17:19:37 PST)
> 6 of these in series


go 12 in series / parrallel and half your esr # hehe, but that would be very $$$$$$$$$$$$$$$$


----------



## kyheng

But power cable with over size insulation also are junk. 
I buy cables based on the specs, not the brand.....
Already using Knu's CCA for 2 years and have no problem with it....


----------



## yogegoy

bd5034 said:


> I know this is sort of O/T but just wanted to point it out... LEDs are not the "future of lighting," that is just hype. They will play a useful part in lighting schemes, but by no means will they replace all other lighting - it's not possible nor is it desirable.
> 
> I work in the lighting industry.


I have a problem seeing when using LED, whenever the target or objective is black vs using an incandescent light source.


----------



## Streetbeat Customz

ChrisB said:


> A capacitor is NOT a substitute for an inadequate electrical system. It takes power (current) to make power (watts) and most of the smaller capacitors will drain faster than one can blink their eyes.
> 
> The larger capacitors, 40 farads or more, have been alleged to help in some situations. Unfortunately, at that pricing point, one would be better off purchasing a second "new technology" fast discharge battery.


And thats that


----------



## Dave_MacKinnon

I love this discussion.. The myth and operation of stiffening caps has been going on for years, and the missinformation is stunning.

Last year, the company I was working for started distributing a line of installation accessories, like Streetwires, Stinger or Audison Conncetion. It's great stuff... I can attest to that, since I helped design it.

As part of the line, they offer a 2-Farad cap with an integrated distribution block and voltmeter. I was tasked with developing a Cap Demonstration for the product launch tour.

So I did.. We had a system with a power supply, a pair of large amplifiers, speakers and a subwoofer. I set the cap up so that I could turn it on or off via a 500 Amp PAC solenoid - I simply switched the ground wire.

When you really go on the system, and the voltage to the amps was causing the illumination on the amp to dim and the voltmeter I installed to dip dramatically, turning the cap on dramatically reduced the effect. 

The question became - could I hear it. Yep - clearly. The bass tightened and the mids and highs became clearer and less distorted. Of course, only when I was really pounding on it, pushing the current delivery limits / speed of the power supply. At regular listening levels, no discernable effect.

Guys, you are all smart.. if you have a theory about something, just try it - that's how I have learned what I have. Develop a hypothesis, set up a test and have that produce the results. No theory, guessing or anything required.


----------



## flexdmc

So much to read up on on this stuff. To a non-technical expert it sure sounds like it makes sense on WHY caps work but maybe that's just advertising at work...


----------



## sonikaccord

Dave_MacKinnon said:


> When you really go on the system, and the voltage to the amps was causing the illumination on the amp to dim and the voltmeter I installed to dip dramatically, turning the cap on dramatically reduced the effect.
> 
> The question became - could I hear it. Yep - clearly. The bass tightened and the mids and highs became clearer and less distorted. Of course, only when I was really pounding on it, pushing the current delivery limits / speed of the power supply. At regular listening levels, no discernable effect.
> 
> Guys, you are all smart.. if you have a theory about something, just try it - that's how I have learned what I have. Develop a hypothesis, set up a test and have that produce the results. No theory, guessing or anything required.


You have to be able to explain why things do the things that they do.
It goes back to your power supply reacting to the current draw. It's the same as an alternator reacting to large current draws. It's a slight delay in the regulator kicking in. The cap fills in that dip in voltage. That's the only thing they do in this application is filter voltage irregularities.

I have an experiment for you. Play a sine wave through that test setup and see what happens.


----------



## Neel

I am surprised nobody has posted a link to the stuff Richard Clark wrote about capacitors. 

So here it is.

Why you don't need a capacitor - Realm of Excursion


----------



## ryomanx

so....what is a cap cell?
Power Acoustik - Products - CAPCELL 
Combining the properties of a battery and a capacitor aren't going to make up for the alternator not being able to provide the need amount of amps your setup may need?


----------



## sonikaccord

That goes back to the conservation of energy thing...The power to the cap has to come from somewhere. If the cap has a large enough capacity to sustain constant voltage then it would work, but the issue is mainly time and capacitance. If you had a long note, and that cap happens to drain then you're back to square one.

Since batteries have tons of capacitance, and they discharge alot of current(it has to start the car), why would you pick a cap over a battery? 

Even the site you posted says this:
"The cap has the ability to empty itself almost instantly on transient notes in music material. "


----------



## ryomanx

sonikaccord said:


> That goes back to the conservation of energy thing...The power to the cap has to come from somewhere. If the cap has a large enough capacity to sustain constant voltage then it would work, but the issue is mainly time and capacitance. If you had a long note, and that cap happens to drain then you're back to square one.
> 
> Since batteries have tons of capacitance, and they discharge alot of current(it has to start the car), why would you pick a cap over a battery?
> 
> Even the site you posted says this:
> "The cap has the ability to empty itself almost instantly on transient
> notes in music material. "


Ok i feel you on that. so let's say, we're pulling power need from a second battery for these transient notes in music. Eventually that battery need to be recharged right? Is the alternator working twice as hard having to charge two batteries or is the alternator ok because it will eventually recharge both batteries? OR! if you're short on amps, then you should just suck it up and get an alternator that producing more amps? (man those things are expensive )


----------



## sonikaccord

ryomanx said:


> Ok i feel you on that. so let's say, we're pulling power need from a second battery for these transient notes in music. Eventually that battery need to be recharged right? Is the alternator working twice as hard having to charge two batteries or is the alternator ok because it will eventually recharge both batteries? OR! if you're short on amps, then you should just suck it up and get an alternator that producing more amps? (man those things are expensive )


Not for transients. They come and go quickly like in milliseconds. If you played music or tones with constant material that demanded more than the alt can supply then you'll drain your battery. If you continue then you'll drain it completely.

The alt will be working at 100% to attempt to charge the batteries. This increases stress and reduces it's life. More batteries means it takes longer to discharge completely so your voltage stays up longer, but the alt still has to charge the batteries and it will be longer for more batteries. This is just how I see it. I'm kind of using common sense to fit everything together lol.

Your best bet would be to take that one good kick to the nuts and get the HO alt.


----------



## Wheres The Butta

I read that Richard Clark bit.

If I am not mistaken, he is operating on a faulty assumption. Someone stop me if I'm out in left field.

He is basing his argument on the assumption that the output of the alternator is static. It's *NOT*. The alternator's output varies with the RPM. At idle, the alt is producing way less, meaning it's very easy to exceed the output and overdraw. If we're talking about a stock alternator's production at idle, we're more in the neighborhood of 70 amps, not hundreds of amps - so his absurd calculations using 500 amps make zero sense. To me, it appears he devised this thought experiment to generate a specific result that reinforces his stance.

Let's say a stereo required 120amps (perfectly reasonable) for a sudden burst, like the one in Metallica's cover of "Loverman". We're only exceeding the alternator's output by 50amps. Not 100, not 300, but 50. Less amps, same ESR, less voltage drop. That means if we use his ESR number of 0.017, the capacitor can provide those 50 amps with voltage drop of only .85. That gives us 13.15v, still significantly above the battery's resting voltage. 

The capacitor may discharge quickly, but it gives that "leading edge" or "attack" that many people attribute to the capacitor. It makes perfect sense to me, but my logic might be wrong. Somebody step in and let me know.


----------



## kyheng

Actually, you can do ourself some simple test to confirm either this cap work or not. What you need is a dual 4ohm 200W sub and an amp that can deliver 300W of power minimum. Then start the test on 2ohm load and measure your voltage on the amp. Follow by 8ohm load and the voltage....
And you will be surprise that running lower ohm load will cause the voltage to drop more while running higher ohm load the voltage won't drop much.... So, the usage of capacitor will be a fact or myth...
But using it as a power conditioner that reject some noise will be good... Like the Pioneer ODR power conditioner is using a 33000uf capacitor and an inductor coil...


----------



## The A Train

IMO, i wouldnt waste my time or money with a cap. the big 3, is definitly the best bang for your buck, followed by 2nd battery and HO alternator. heres some basic info on capacitors that i posted on another thread on another forum.


Physically, a capacitor is an electical component consisting of two conducting surfaces separated by a non-conductor (dielectric). In electrical terms, a capacitor is an electrical component that stores electrical charge when voltage is applied. The closer the plates, the stronger the electric field produced. The greater the charge stored on the plates, the stonger the field produced.

This field represents the storage of electric energy. This energy comes from a source and can be returned to a circuit when the source is removed.

Once a capacitor is hooked up to a power supply, the electrons do not travel through the non-conductive dielectric material between the capacitor’s plates. This electrons accumulate on that side of the capacitor creating an excess of electrons resulting in a negative charge. The electrons orbit passes in the through the dielectric and are repelled by the negative polarity of the capacitor.

As these electrons build up creating a negative side to the capacitor, the electrons are more and more attracted to the capacitor’s positive side. Once sufficient charging current has passed to cause the capacitor’s voltage to equal the source voltage, no more current can flow. The capacitor is now fully charged.

Voltage doesn’t pass through this dielectric material but it acts that way due to the movement of electrons on either side. Once a capacitor is charged, it will equal the source voltage. If the source voltage increases/decreases, the capacitor will do so likewise.

The unit of capacitance is the farad. Common capacitors for car stereo installations would be around 1 farad. A farad is the amount of capacitance where a charge of 1 coulomb develops a potential difference of 1 volt across the capacitor plates.

C=Q/V Q=CV V=Q/C
V=Voltage
Q=Coulombs
C=Capacitance in Farads

Coulomb’s Law F=(kQ1XQ2)/(d2)











Before your charge your capacitor, you must discharge the capacitor. To do this, just short out the positive and ground leads very carefully and hold it for a few seconds to be sure that all the stored voltage is released. To properly charge a capacitor, use a resistor between your battery and your capacitor. Use roughly a 1kΩ resistor here. Hook up the resistor to the power wire and let the capacitor charge for roughly 5-25 sec.


----------



## Wheres The Butta

Let me give full disclosure. The reason this topic is dear to my heart is as follows:

I already have my "big three" wires upgraded, and have two group 31 batteries to sustain my stereo. My stock alternator produces sufficient power such that I can play at a moderate volume indefinitely with zero voltage drop. As I increase the volume, I eventually reach a point where the voltage drops to 12.8, where it will remain for a LONG time before I exhaust my battery supply. 

At my preferred listening level, I have no sustained voltage drop, but dip below 13v on hard bass notes. 

I recently purchased an 8 farad capacitor with the idea that it would help smooth out any minor fluctuation in the power my amplifiers are getting. I also hoped that it would help with the "attack" aka leading edge of forceful notes because of the reportedly superior discharge rate. I have been told that the capacitor can react faster than a battery, faster than an alternator, and thus allows better dynamics. I have yet to confirm this to my satisfaction. 

I have the capacitor sitting on my kitchen table right now. I haven't installed it yet because this thread has me unsure. I want to find out if the capacitor actually has a purpose in car audio or should I just turn around and sell the unit I purchased. 

Can it actually "condition" or "smooth" the power? Can the fast discharge translate to better dynamics?


----------



## sonikaccord

bd5034 said:


> Can it actually "condition" or "smooth" the power? Can the fast discharge translate to better dynamics?


Yes it can be used as a power conditioner. Yes it can help dynamics because the amps will get a more consistent power delivery. The amount that it helps depends on the power supply in the amp.


----------



## Sarthos

Yes, on some older amps with outdated power supplies or old amps with failing parts it can help give them constant power etc etc etc. But tbh, you're better off spending some money to either refurbish, modify, or replace the amp than to try and fix it with a capacitor


----------



## Wheres The Butta

Sarthos said:


> Yes, on some older amps with outdated power supplies or old amps with failing parts it can help give them constant power etc etc etc. But tbh, you're better off spending some money to either refurbish, modify, or replace the amp than to try and fix it with a capacitor


What about a MB Quart DSC4125? Sundown SAZ-1500D?

Think the extra capacitance can benefit them a bit? What about for a MS-8?

I know specifics are tough. I just want to know your personal opinion, that's all.


----------



## AudioBob

I have used capacitors in many installs where the benefits were noticeable. You are going to see people on this site argue all day for and against them calling them a band aid or useless. I would say that if you have it try it for yourself and let everyone on this thread know your results.

My experience is that it does "Condition" because I have seen them remove system noise and alternator whine. I have also seen them do a great job with stopping or minimizing voltage drops on music that is very dynamic or with difficult passages.

I personally feel that they have their place, but don't expect any magic fixes if your system has other major power supply issues.


----------



## Wheres The Butta

AudioBob said:


> I have used capacitors in many installs where the benefits were noticeable. You are going to see people on this site argue all day for and against them calling them a band aid or useless. I would say that if you have it *try it for yourself and let everyone on this thread know your results.
> *
> My experience is that it does "Condition" because I have seen them remove system noise and alternator whine. I have also seen them do a great job with stopping or minimizing voltage drops on music that is very dynamic or with difficult passages.
> 
> I personally feel that they have their place, but don't expect any magic fixes if your system has other major power supply issues.


Sounds like a terrific idea. I will be sure to contribute my personal experience.


----------



## Sarthos

bd5034 said:


> What about a MB Quart DSC4125? Sundown SAZ-1500D?
> 
> Think the extra capacitance can benefit them a bit? What about for a MS-8?
> 
> I know specifics are tough. I just want to know your personal opinion, that's all.


Never used either of those amps. Never actually seen one in person either. I have no idea how adding extra capacitance can help an MS-8 though.


----------



## Wheres The Butta

I'll let you guys know my own results.


----------



## starboy869

The things is Why spend $300+ on a new/used high output alt and $250+ on a good low esr battery when a $150 cap would do the job? 

I say if you have a modest system. At least do a big 2 (battery to chassis and engine to battery wires). Then if your still exp. a drop in voltage then install a cap 2fd or so just to smooth out that small voltage dip. If it fixes your issue +thumbs up and you just saved yourself $400+

Yes the caps takes and store power. That's the running argument I see a lot. However a second battery stores power which is another load on the alt. hmmm.


----------



## IBcivic

starboy869 said:


> However a second battery stores power which is another load on the alt. hmmm.


S-Boy is correct
This statement always cracks me up. There is absolutely no difference between adding a battery or using a single oversized batt. Think about it.

A larger fuel tank, requires a larger filler nozzle?


----------



## tnbubba

depends on the amps supply circuit.. most unregulated amps may/can benefit from a cap.. most regulated amps seems to do better with just making sure they get the voltage form the bat.. just a general observation but if you think about it.. unregulated amps have not the power filtering reserves that a regulated amp does so the caps does help!


----------



## jsun_g

Yep. Think of it as "pay me now" or "pay me later". The capacitor by nature resists a change in voltge, hence its use in controlling voltage ripple. When a cap discharges the energy it's stored, for example during a music crescendo, it has to draw upon the alternator during "quiet time" to re-charge ("pay me later"). One would think a really large cap would have a better benefit for non-regulated amplifiers.



amitaF said:


> S-Boy is correct
> This statement always cracks me up. There is absolutely no difference between adding a battery or using a single oversized batt. Think about it.
> 
> A larger fuel tank, requires a larger filler nozzle?


----------



## sonikaccord

This is why capacitors are used.
YouTube - ‪Do Capacitors Do Anything - The Truth About Car Audio Capacitors‬‏


----------



## tnbubba

real simple.. ****ty switching noise from a class D amp.. 
a good amp would have adequate on board filtering caps/ and or shielding.

DUH the cap is nuthing more that a filter...
didn't say anything about stiffening the power supply!


BTW if you go to DIY audio and check there is a thread discussing why all the home manufacturers have basically abandoned digitial amps. cost...
that's right to make a good digital amp the design and manufacturing cost are much greater than a decent a/b amp.


so basically the cap is nothing more that a crutch for a poorly designed class D switching amp!


----------



## sonikaccord

The amp didn't have to be class D to induce noise into the signal...it's just easier esp with a crappy amp. If he tried that with the JL HD series or a ZED amp, I bet his results would be a lot less extreme.
Added capacitance is never a bad thing and car amps have internal space constraints.
Stiffening means removing noise/cleaning up power supply line. Voltage drop is a form of noise.

Really? So home audio is leaving class D but car audio is embracing it. I have to find that thread, sounds like a good read.


----------



## VWGuy

I was told by a friend that a cap cannot replace a good battery. I will be running 2 batteries in parallel on my vw bus.


----------



## ATOMICTECH62

FWIW, I am almost 50 years old and have been into car audio since I was 16.I have been through more systems than anyone I know and yet I still find I learn new things every day.
I could never understand why anyone would waste that kind of money on a cap when they could go to Sears and buy a die hard 900cca battery with thousands of times the power for less money.There is a formula to convert joules to watts(I googled it a long time ago)and 1 farad at 12volts is = to about 70 watts.Seemed like a no brainer to me.

Anyway,now I have a 01 blazer with a factory alt and a newer 850amp battery,2ga power wire going to 2 mac mc431m and a jl 500/1 running 5way active and it sounded awesome but i had a massive voltage drop when cranking and I knew this would happen.I know better than to drive around trying to be the loudest moron on the block.
I like to listen to music loud but only for short durations like 1 song then turn it down to give my alt a break.
I was about to add an extra battery because I know my amps would sound better and my headlights dimmed soooo bad people had to be laughing, when I came across a great deal on some rockford 1 farad caps.I got 5 of them for 100 bucks nib and intended on reselling them for a profit.One night driving around with my lights dimming so bad I looked like a strobe light on wheels I decided to try one since it was dark and I thought I could do an A/B comparison.
A couple feet of 4ga wire,some ring terminals and a half hour later I later I took of up the road.I couldnt tell much of a difference until I cranked it to the point that the power guard led's started to flash on the macs and WOW major improvement.Every thing sounded cleaner,more detail in the mids and highs,bass was much tighter.
However it didnt do crap for my headlights,nada,zip,zero.
This is not just my opinion,every person who herd my system before noticed it to.I get someone in it and say listen to this and they would say wow what did you do.
Granted this system was starved for energy,and I think any upgrade would have been audible but that 1 cap made a believer out of me.
Also,these are all regulated amplifiers of the highest quality so I am sure that lesser amps would benefit even more.
Caps did not fix my problem nor will they fix any power starved system but they can help.Now I need that extra battery and an alternator out of a wrecker.


----------



## tnbubba

bet if you fixed the rest the cap would not have made an audible difference


----------



## kyheng

Actually a cap can be a power filter..... Which makes more sense most of the time....


----------



## ATOMICTECH62

You could be right.
I was in the process of changing the system around when i noticed this thread so Im going to find out if the caps will make an improvement this time around also.
I just bought another battery and some 1/0 gauge wire, Im changing out the 500/1 for an mtx 92001 and adding another 12.
I just need to pick up an audio control dsx and find the time to finish it,so it will be a few weeks.
I also picked up an assortment of buss bars for the caps,so I can experiment with how many it takes to makes an improvement and what is the practical limit.
Im still thinking on which way to go with alternator problem.But thats another story.
Like I said before,that 1 cap made such a big difference in SQ at higher volumes Im sure it will help this time around also.If it doesnt I will eat crow and stick with my extra battery theory.


----------



## tnbubba

add up you current draw for you amps.. then add that to the what it takes to run you vehicle with lights and a/c and fans and cooling fans.. if your alternator does not put out 70% of that your not going to fix anything with a cap.. ah I won't divulge the secret to figuring out how much ampacity battery you need and Low esr batteries are nto the cure.. I've seen super overpriced low esr batts have a shiyty current discharge curve.

It's simply how fast can your electrical system recover. or supply.. that is two totally separate issues but both have to be addressed at once. A cap is simply a crutch or at best a noise filter..


----------



## EvilWagn

hmmm good info here. Thanks all.

Most of the discussion seems to revolve around quantity, I'm curious on the quality aspect. My current car has solid clean power, but I've dealt with some nastiness before.

In a lower powered system (say under 500 rms total) where power consumption isn't an issue and voltage dips are not notable (without meter); Would adding a (quality) cap be beneficial in terms of sq? I realize this is a huge generalization, but just as a starting point...


----------



## gtsdohcvvtli

FartinInTheTub said:


> I am a UNION electrician and proud of it. trained in not only AC but DC.. as well as complex motor controls, relays, etc,... I know what i'm doing. i don't need to defend what I know to 24 and 25 year old kids. I was trying to be civil and polite to you by simply responding. try doing the same.
> 
> ps.. I also have a degree in electrical engineering from The university of California, Berkeley but I chose to work in the field since sitting behind a desk doing CAD drawings bores the **** out of me. I am also an Electrical contractor. thanks again for your opinions... I will consider them when doing my install.


What I really hate is when an electrician installs his deck with wire nuts. And then when the 40 year old electrician teaches his son, the 20 year old then starts installing deck with wire nuts. Then when you explain to the son why its wrong, your crazy cause his dads been an electrician for 20 years







Dont hate on me. this is my first post. just had to say it. lol


----------



## TrickyRicky

Wire nuts only work on solid copper, thats why they use them for home/commercial. But when it comes to multi-fine strands like car audio (which requires more current) you pretty much have to hand twist add a little solder and some shrink tubing for a real good connection & protection. Ofcourse they sell couplers but even those fail sometimes, where solder pretty much helds pretty well.

But I have seen some ghetto installs with wire nuts, and I just keep my mouth shut and let them learn the hard way once that puppy falls off and creates a short or even a fire is a well lesson thought.


----------



## subwoofery

Couple of things, Andy Wehmeyer said that the Big 3 was a waste of time and money - don't remember the exact reason he gave but it's on DIYMA... 
^ I dunno, I did it anyway coz I have time to waste and money to spare lol - did not notice any improvement to be honest - can't hurt to do it though 

I also do not believe in Cap to make up for the lack of power however I do believe that they can filter out noise and solve a lot of noise related problems... 

I upgraded my alt, for me it's actually the best bang for the buck. During my time off from work, I took out my alt and sent it to have it upgraded. Used to be 90A max and now it's 110A @ idle to 160A max. One of the best $220 I spent on my audio. 
In 3 years, I killed 2 of the biggest yellow top Optima coz my alt couldn't recharge my rear batteries fast enough. 

Kelvin


----------



## upgrayedd

This is like watching politicians argue. Saying repeat a voltage drop test with a sine wave is inane. We do not listen to sine waves, we listen to dynamic music and many of us have small systems with MAYBE a PEAK draw at or slightly above our alts available output or even close, hell lets say that draw of musical peak, lights, efi, blower motor, etc is right at our alts peak. Just because the alt CAN deliver xx current, does not mean it can do it NOW. There is a slight delay with the regulator. The battery absorbs some of this, but it still has some delay. Dont believe me? Turn on your lights, watch them and your running voltage when a cooling fan or blower motor on high is switched on, you will see a momentary voltage drop that quickly returns to normal. Does this mean the charging system is insufficient? nope. Just because we replace the fan with music, does not mean everything is insufficient. This is where a cap can help. By nature of the whole situation, I would imagine they would have more of an advantage on an unregulated or cheaper powersupply, this could explain how they work for some and not others. 

I think it goes without saying that if you are pounding away and you are dropping to or below batt voltage every note, or with the stereo on your charging voltage is low; you have real issues. I Think caps have their place beyond the filtering aspect(it kind of is filtering anyway), but many people feel or are told that they fill fix their "light dimming" when their poor 70amp alt is struggling to even hit 13v between drops to 11. That is where the problem lies.


----------



## AKheathen

with all the sidetracking and profuse mentioning of "EE", i diddn't see if it was mentioned, but a capcitor/bank is real fast-acting compared to almost any battery you will find. the chemical reaction and other properties of a battery are going to provide quite a bit of resistance to the ripple/noise/spikes and drops of the electrical system, so a cap can do well to clean it up, but every other point has been touched on. it will not give any more power than it takes, etc..


----------



## chris2013

if we have people with a math background on here "EE" then it should be quite easy to work up some differential equations with various forcing fuctions! we should use: a step function, some kind of fourier or laplace signal representing music, a dirac delta fuction. 

set up the diff eq and graph the resulting voltage in mat lab/ maple or whatever and we can explain it to everyone

from the differential equation we can plug in as much capacitance and current demand as we wish and plot the voltage results- in short this is how it's really done

the equations are related to a mass on a spring with shock absorber that is forced to move! same as a car! mass on a spring with shocks! certain bumps can't be felt, certain ones can, certain ones are uncomfortable and driving off a cliff is deadly


----------



## hotbutta

Wheres The Butta said:


> I know this is sort of O/T but just wanted to point it out... LEDs are not the "future of lighting," that is just hype. They will play a useful part in lighting schemes, but by no means will they replace all other lighting - it's not possible nor is it desirable.
> 
> I work in the lighting industry.


Here is the Butta. And you are EATING your l.e.d. comment now, ain't cha?


----------



## maggie-g

hotbutta said:


> Here is the Butta. And you are EATING your l.e.d. comment now, ain't cha?


wtf??? a 4 year old thread for this comment?


----------



## TrickyRicky

Only because Zombie Jesus said so....lol.


----------



## hotbutta

Four years is the "future". Anyway, Tony D'amore has proven (youtube) that caps do improve transient power. And lower long term wattage. However, he did use an ordinary electrolytic. Next test should be an ultra capacitor. That's what I was searching for and brought me to page 2 of this thread.


----------



## TrickyRicky

if you have one you can send it to me and I'll do some tests.


----------



## hotbutta

The reason for my search this morning was to find them. There are people selling these in banks of 6 on ebay. I want to find the sources to get a lot of them. They are in hybrid city buses and such. To the right person, these are worthless, and I am looking for that person. Look at Taylor Fade YouTube comparison. Amazing


----------



## chris2013

TrickyRicky said:


> if you have one you can send it to me and I'll do some tests.


No need to actually test anything. This is a typical differential equation a phone app can solve in ur hand.


----------



## TrickyRicky

chris2013 said:


> No need to actually test anything. This is a typical differential equation a phone app can solve in ur hand.


Really? Is that app going to measure voltage drop, current, wattage output and check for distortion & clipping?


----------



## chris2013

TrickyRicky said:


> Really? Is that app going to measure voltage drop, current, wattage output and check for distortion & clipping?


The solutions are the conditions seen on the power supply. What an amplifier does under those condition is totally determined by the characteristics of the device itself.

You do realize that most of the worlds engineering in done in simultion before they ever build anything, yet they seem to somehow be able to know how a thing is gonna behave. Maybe the math/physics is all voodoo?


----------



## gstokes

Capacitors do work but there are much better options to be had..

Hint: Kinetik


----------



## The Car Audio Chronicles

FartinInTheTub said:


> I use an Alumapro Carbon 15 farad and I will swear by it. i had light dimming issues and once added these symptoms went away completely. Not to mention that this does my power and ground distribution nicely. I do agree however that most caps are a bandaid. I used to have a Stinger 1 farad capacitor and it wasn't very effective.


Knowing that your cars alternator was designed to have somewhere around 30% or so of reserve power, how much reserve power does your alternator have versus what your amp is trying to draw? If your amp is asking for more than the reserve, then that is why your lights are dimming. The cap will only mask the real issue. Caps were not made to fix light dimming issues. I believe they were made for competition settings to store energy to get the most out of that first bass drop. 

Its usually recommended to first upgrade your wiring between alternator and battery if you are having light dimming issues. Even look at adding additional grounds in your system. Only after that would you look at replacing your existing battery if the problem still persists. A battery that was designed to handle additional load. Only after these steps would you look at replacing the alternator. And you don't have to replace it. There are places where you can have your existing alternator respun for additional amperage. 

Now with that being said, I am curious to know what amp and sub you have that were causing these issues?


----------



## cajunner

if I were going to try and install caps, I'd make 3 banks of 6 ultracaps or whatever, something like 40 farads per bank, and I'd wire them on servo switches to drop at specific voltages.

My understanding of the capacitor bank discharge is that within a couple of seconds of 30 hz bass, you can expect a 40 farad bank to be fully discharged, at which point you would have a servo switch contacts to add another bank, which would drop another 2 second interval of high voltage swing into the amp, and then the third bank would come in at the 6 second relay, or servo setting.

Maybe there's a way to do half-sine charge, where the cap only loads during the woofer return or negative, delivering the back EMF to the amp that it could store capacitor style...

then the cap banks could recharge behind the one discharging, and over the three separate leapfrog servo lands, continually discharge at high voltage never allowing the system to dive into battery voltage?

that would be cool...


----------



## Ultimateherts

cajunner said:


> if I were going to try and install caps, I'd make 3 banks of 6 ultracaps or whatever, something like 40 farads per bank, and I'd wire them on servo switches to drop at specific voltages.
> 
> My understanding of the capacitor bank discharge is that within a couple of seconds of 30 hz bass, you can expect a 40 farad bank to be fully discharged, at which point you would have a servo switch contacts to add another bank, which would drop another 2 second interval of high voltage swing into the amp, and then the third bank would come in at the 6 second relay, or servo setting.
> 
> Maybe there's a way to do half-sine charge, where the cap only loads during the woofer return or negative, delivering the back EMF to the amp that it could store capacitor style...
> 
> then the cap banks could recharge behind the one discharging, and over the three separate leapfrog servo lands, continually discharge at high voltage never allowing the system to dive into battery voltage?
> 
> that would be cool...


Sounds like a kickstarter campaign!


----------



## gckless

cajunner said:


> if I were going to try and install caps, I'd make 3 banks of 6 ultracaps or whatever, something like 40 farads per bank, and I'd wire them on servo switches to drop at specific voltages.
> 
> My understanding of the capacitor bank discharge is that within a couple of seconds of 30 hz bass, you can expect a 40 farad bank to be fully discharged, at which point you would have a servo switch contacts to add another bank, which would drop another 2 second interval of high voltage swing into the amp, and then the third bank would come in at the 6 second relay, or servo setting.
> 
> Maybe there's a way to do half-sine charge, where the cap only loads during the woofer return or negative, delivering the back EMF to the amp that it could store capacitor style...
> 
> then the cap banks could recharge behind the one discharging, and over the three separate leapfrog servo lands, continually discharge at high voltage never allowing the system to dive into battery voltage?
> 
> that would be cool...


What's the difference between having that complex system that's more prone to failure and having just three banks in parallel?


----------



## gckless

gstokes said:


> Capacitors do work but there are much better options to be had..
> 
> Hint: Kinetik


I'm failing to see what you're getting at.


----------



## stopdrpnro

so I've always thought of capacitors like this:

you have an unexpected bill (new lil jon song) due immediately. your main job(alternator) doesn't pay out for 2 weeks (time to sense load and increase output) .your options are get a part time job ( battery) but you'd have to work a day(a second) before you get paid or just swing by the bank and withdraw from savings ( capacitor) immediately. you'll have to replace the funds once you get paid in 2 weeks but that money is still there


----------



## Pianista

FartinInTheTub said:


> I am a UNION electrician and proud of it. trained in not only AC but DC.. as well as complex motor controls, relays, etc,... I know what i'm doing. i don't need to defend what I know to 24 and 25 year old kids. I was trying to be civil and polite to you by simply responding. try doing the same.
> 
> ps.. I also have a degree in electrical engineering from The university of California, Berkeley but I chose to work in the field since sitting behind a desk doing CAD drawings bores the **** out of me. I am also an Electrical contractor. thanks again for your opinions... I will consider them when doing my install.


I don't belive you. You even don't know what's happening with your system. 15F cap... lol.... sure. 15kw amps with a 55A optima batt and a 80A alternator... funny

Un saludo del pianista


----------



## grinkeeper

FartinInTheTub said:


> I am a UNION electrician and proud of it. trained in not only AC but DC.. as well as complex motor controls, relays, etc,... I know what i'm doing. i don't need to defend what I know to 24 and 25 year old kids. I was trying to be civil and polite to you by simply responding. try doing the same.
> 
> ps.. I also have a degree in electrical engineering from The university of California, Berkeley but I chose to work in the field since sitting behind a desk doing CAD drawings bores the **** out of me. I am also an Electrical contractor. thanks again for your opinions... I will consider them when doing my install.


Your being very respectful and I for one respect what your saying.


----------



## tomtomjr

Older thread. But, here is the history of adding capacitors inline. (From memory) This might shed some light on how it started in car audio. The first that I know of is Wayne Harris used a LOT of capacitors inline in the Hearse/Ambulance (and the MonteCarlo/Regal/Cutlass) that was big news in the early 80's. Also a company called Zapco used something called the ESM (energy storage module) 1975-1991 or so in the 3 piece amplifier. The ESM was 4 inline caps inside of a box. The ESM box was optional between the Power supply and Amplifier. All were part of a component amp. The power supply was output 30 to 40vdc depending on model ps150/ps200. Then the optional ESM (energy storage module), then the amp itself (tiny, 200w). I am very partial to these amp setups, and just cant get enough of them. Anyway, from what my knowledge is, these are the first production use of them. They do help keep the lights from dimming during a heavy bass note. Unless you are running 4 or more on a single battery. Since then, other companies have made caps that go pre-power supply. This is the only one I can remember offhand that was optional and went between the power supply suoply and output of the amp. It did make a difference. And according to the manual (if I remember right) gave a 20 watt boost making the 151 amp with the PS 200 power supply a total of 220w. The PS150 power supply used with the 150/151 amp also gave it a 10% boost. Anyway, that is the history of capicitors used in car audio as I remember it. I haven't had much luck with pre capacitors (modern type) since. Others swear by them. I always had better luck installing more batteries, and was a cheaper route. Also, I preferred not to run Isolators on the batteries. This was 20-25+ yrs ago. I am sure things have chsnged since then. This is probably not all fact, just how I remember it from my area, and from way back then.
tomtomjr


----------

