Information About Capacitors

[91Chevy]

Capacitors can make or break your sound system. When used in the proper application, Capacitors are very beneficial to your vehicle’s electrical system. It can stop your system from dropping to dangerously low levels when your system has high power demands. However, when used in improper applications, they can often cause serious issues.

How a capacitor works: Capacitors store an electrical charge, and discharge that charge very quickly when required. The battery charges the capacitor, and when the system is drawing excessive current, the capacitor will discharge, then continue to recharge itself.

The proper application for a capacitor: Say you have a sound system, with proper charging system, such as a high-output alternator, as well as multiple high quality batteries. The system works flawlessly; however, whenever the bass hits hard notes, you get dimming. Yet when the heavy notes cease, the dimming ceases. This is because your charging system is capable of feeding adequate power to your system under ordinary circumstances. Yet when the heavy bass notes hit, it draws a very large amount of current for a fraction of a second, which your charging system cannot keep up with. In this case, the capacitor discharges, sending addition current and allowing your charging system to keep up. Since your charging system is powerful enough to feed your system under ordinary circumstances, it can also recharge the capacitor without hindering the performance of your audio system.

The improper application for a capacitor: Your sound system gets dimming during regular play; your charging system is just incapable of providing enough power to supply your sound system. So you decide to install a capacitor, as you’ve been told it will help with your dimming. You charge your capacitor, and go to test out your system, just to find that your dimming either hasn’t been fixed, or has even worsened. This is because your charging system cannot supply enough power to power your audio system, so the capacitor discharges to ‘help’ it out. Since the capacitor has discharged, it needs to recharge. But since your charging system can’t keep up as it is, it puts even more of a strain on your charging system to both charge the capacitor and keep your sound system playing.

Why the ‘Big 3’ is beneficial: By upgrading the Alternator + to Battery +, Chassis to Battery -, and Engine Block to Chassis wires, you make your charging system more efficient. There’s less resistance, allowing more of the amperage coming from your alternator to reach the battery, and less to be dissipated as heat. If your battery recharges faster, it will help or solve dimming in most occasions.

Summarized, a capacitor is very useful when running a system that is equipped with a High-output electrical system, capable of handling charging the capacitor as well as the batteries. It's not wise to run a capacitor on a stock electrical system which only produces just enough power to charge the battery, as well as powering the system. Adding a capacitor will simply put even more strain on the charging system, making it's job even harder that it already was.

More Information:

Posted by mvw2: http://caraudioforum.com/showpost.ph...0&postcount=13
Posted by Rare177: http://caraudioforum.com/showpost.ph...5&postcount=15
Posted by greybush: http://caraudioforum.com/showpost.ph...7&postcount=16
Posted by sandt38: http://caraudioforum.com/showpost.ph...4&postcount=19

[91Chevy]

If there's anything I missed or any incorrect information drop me a PM and I'll fix it.

[Wazzup592]

Maybe this will cease all of the dumb capacitor questions lately

[91Chevy]

Originally Posted by Wazzup592 Maybe this will cease all of the dumb capacitor questions lately

That's the plan I wouldn't call them 'dumb', just 'uninformed' or 'misinformed'

[Wazzup592]

I guess you're right

[Rare177]

rep on recharge.

may i add, the use of a cap, or the only way i would use one, is to keep my electrical system up high, without one, when bass hits you will drop down to battery level (around 12 volts) a cap can be used to keep your system up around the 14v mark, this is the only time i would use one, and this would be with a HO alternator of some sort.

they are not good for fixing dimming issues or voltage drops due to a weak alternator.

[Suprefly]

I like this thread

[91Chevy]

Originally Posted by Rare177 rep on recharge. may i add, the use of a cap, or the only way i would use one, is to keep my electrical system up high, without one, when bass hits you will drop down to battery level (around 12 volts) a cap can be used to keep your system up around the 14v mark, this is the only time i would use one, and this would be with a HO alternator of some sort. they are not good for fixing dimming issues or voltage drops due to a weak alternator.

Edited to include a tidbit of that

Originally Posted by Suprefly I like this thread

Thank you very much. I'm hoping a mod will like it as well and sticky it.

[subaru_legacy]

yay you used my thingy kind of lol btw good thread

[Rare177]

Originally Posted by subaru_legacy yay you used my thingy kind of lol btw good thread

please tell me you're atleast older than 12?

[subaru_legacy]

lol yea im 16 just really tired atm and not thinking straight. too much on my mind at this point.

[91Chevy]

Thanks guys. If there's anything you feel needs to be added, PM it to me and I'll write it up tomorrow after work.

[mvw2]

A typical 100 amp alternator will put out 1440 watts continuous, some of which is used by the car's electricals. A typical battery has a cranking amp capacity of 500-1000 amps continuous (temp and design dependent). This means the battery can support a continuous pull of around 6000 to 12000 watts.

The biggest thing seen is that drop from 14.4v to 12v and the little bit of dimming this can cause. A person can step to a higher amperage alternator and provide a higher capability from the start. A battery really doesn't matter much at all other then storage capacity. The choice in a battery and the use of multiple batteries is more of a matter of running the audio system for extended periods of time when the car is off. When the car is on, the battery does virtually nothing.

I personally blame the amp more so then the car. I would figure a good amp will be built well enough to have sufficient internal storage and to provide a more steady draw from the car's electrical system. One might try to focus on buying a better amp or buy one that is geared for more power, i.e. plenty of overhead. By keeping the fluctuations within the amp, we don't stress the rest of the car at all. In my eyes, I see the cap as a band-aid rather then a proper tool. Then again, I really don't know enough about amp design to all out blame the amp. Once someone gets to say 2kw or more of output, maybe no amp can retain a smooth current draw on the car's electrical system. Still, I think it could be fixed at the amp before the car ever sees anything. That's my take on this at least. Caps mainly exist in car audio as a marketable and profitable gimmick. There is some usefulness, but really they aren't the correct answer.

[ninjawhiteboy12]

a question for this thread, what is the rule of thumb for size alternator to how many wrms you are running say:
1000 wrms= x alternator
2000 wrms= x alternator
3000 wrms= x alternator
ect.

[Rare177]

Originally Posted by ninjawhiteboy12 a question for this thread, what is the rule of thumb for size alternator to how many wrms you are running say: 1000 wrms= x alternator 2000 wrms= x alternator 3000 wrms= x alternator ect.

this is hard to assume, depends on the music you listen to, depends on how efficient the amp is, rock music has less heavy bass demand compared to say rap music.

i would say 80amps is good for about 1000 watts, but once again this depends on alot of things, one way people work it out, which isn't very accurate due to inefficiency, is watts / voltage = required amperage, so lets say, 1000wrms / 14 = 71amps, this does not account that an amp is never 100% efficient.

for example, i own a car with a 100amp alternator, as of now, my system currently is only 1000 watts, 250x2 for speakers, 500 for the substage, problem is though, both my speakers and substage are class a/b, not so efficient, even with the big 3 done, i still get voltage drops and major dimming with the volume up, now i listen to alot of bass heavy music, like jeezy etc.

with amps, bigger is always better, you can never have too much power supplied to your system.