Capacitors

[xXnavyseal2Xx]

Hi I was wondering why most people say don't use capacitors in a car audio build. Can someone please explain in noob format.

Thanks,

Have a nice day

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[Chriszle 10+ year member]

If your running enough power to where you need to upgrade your electrical, normal capacitors do not have enough energy stored to actually help. A secondary battery provides much more energy storage. Now if you are talking about a bank of ultracapacitors, that is a different story.

 

[argenis69 10+ year member]

I'm also interested in this

 

[jrdnhsnbrg 10+ year member]

I think it was calculated that a decent AGM battery can store over 10,000x more electricity than a regular capacitor, and from what I've gathered your average capacitor simply delays a voltage drop, because as soon as a cap discharges it immediately wants to recharge. A battery, on the other hand, will discharge what electricity is needed then will recharge when the alternator (or other power source) charges it. I'm not 100% sure, though.

 

[bubbagumper6 5,000+ posts]

I think it was calculated that a decent AGM battery can store over 10,000x more electricity than a regular capacitor, and from what I've gathered your average capacitor simply delays a voltage drop, because as soon as a cap discharges it immediately wants to recharge. A battery, on the other hand, will discharge what electricity is needed then will recharge when the alternator (or other power source) charges it. I'm not 100% sure, though.

Both a capacitor and a battery will present a load on the alternator as soon as their resting voltage drops below the alt's charging voltage. The difference being capacitors will discharge much MUCH faster than batteries but can hold far less total energy so if the demand is significant the cap will completely discharge before the demand is satisfied. Batteries on the other hand discharge much slower so there will be a more significant delay between when the demand starts and when the battery actually begins supplying current. However batteries hold vast amounts of energy so they can handle much larger demands for longer periods of time. Both need recharged in the end however.

The main reason capacitors aren't used in the car audio world is because they simply do not hold enough energy to make a difference at the high current levels most systems run at. It would be like trying to supplement a fire hose with a 2 liter bottle of water connected to it...

 

[jrdnhsnbrg 10+ year member]

Ah I see, thanks for the correction. I like the metaphor, too //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Jroo 10+ year member]

Caps get a bad rap. If you have electrical problems, a cap is not going to help you. You need to look at things like wire, battery, and alts. I have used and will continue to use caps, but I look at them as a filter for noise. They have a small benefit on my sub amps, but mainly use it filter out noise.

 

[Full Tilt 10+ year member]

Caps get a bad rap. If you have electrical problems, a cap is not going to help you. You need to look at things like wire, battery, and alts. I have used and will continue to use caps, but I look at them as a filter for noise. They have a small benefit on my sub amps, but mainly use it filter out noise.

And how, exactly, does it do that?

 

[jrdnhsnbrg 10+ year member]

And how, exactly, does it do that?

I've actually heard of this working, I saw a YouTube video of someone who hooked up an o-scope somehow to his car's electrical system so you could see the amount of noise throughout the system with and without the cap hooked up. The cap made a big difference.

 

[bubbagumper6 5,000+ posts]

And how, exactly, does it do that?

Capacitors will act as a ripple filter when connected in parallel to a DC power source...basic electrical

However that is just about the ONLY thing common car audio caps are good for and any decent amplifier will have it's own internal ripple filter caps so it's kind of a moot point

 

[Full Tilt 10+ year member]

Capacitors will act as a ripple filter when connected in parallel to a DC power source...basic electrical
However that is just about the ONLY thing common car audio caps are good for and any decent amplifier will have it's own internal ripple filter caps so it's kind of a moot point

I was asking more along the lines of how it does so. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[ciaonzo 5,000+ posts]

Both a capacitor and a battery will present a load on the alternator as soon as their resting voltage drops below the alt's charging voltage. The difference being capacitors will discharge much MUCH faster than batteries but can hold far less total energy so if the demand is significant the cap will completely discharge before the demand is satisfied. Batteries on the other hand discharge much slower so there will be a more significant delay between when the demand starts and when the battery actually begins supplying current. However batteries hold vast amounts of energy so they can handle much larger demands for longer periods of time. Both need recharged in the end however.
The main reason capacitors aren't used in the car audio world is because they simply do not hold enough energy to make a difference at the high current levels most systems run at. It would be like trying to supplement a fire hose with a 2 liter bottle of water connected to it...

Nice job, bro.

 

[bubbagumper6 5,000+ posts]

I was asking more along the lines of how it does so. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

Oh sorry, I misunderstood your tone...

If the DC voltage level isn't constant (i.e. has noise or ripples) the capacitor can charge/discharge so quickly it smooths out any dips or peaks in the waveform. Basically when the voltage dips the capacitor can supply current to keep the actual output voltage stable, likewise when it peaks the capacitor absorbs the excess energy. Now this is all relative to the specs of the capacitor and how much actual capacitance it has.

 

[CrossoverOre 10+ year member]

i personally use caps all the time but in more moderate systems and not the high spl types that a lot of guys on here like to build. mainly I use them as supplement power when using 4 ch amps and sub amps. When some setups with multiple amps and especially when somewhat powerful sub amps are used and 4ch are used for the mid range the 4ch amp will suffer greatly from power being robbed by the sub amp. Caps clear up the mud from the 4ch by supplying juice when bass notes hit. Keep in mind this is also reffering to everyday listening music and not "HOW LOUD ARE MY SUBS RIGHT NOW!!"

 

[hispls 5,000+ posts]

i personally use caps all the time but in more moderate systems and not the high spl types that a lot of guys on here like to build. mainly I use them as supplement power when using 4 ch amps and sub amps. When some setups with multiple amps and especially when somewhat powerful sub amps are used and 4ch are used for the mid range the 4ch amp will suffer greatly from power being robbed by the sub amp. Caps clear up the mud from the 4ch by supplying juice when bass notes hit. Keep in mind this is also reffering to everyday listening music and not "HOW LOUD ARE MY SUBS RIGHT NOW!!"

Do this little experiment. Play your amps at the level where you think the caps are helping and then unplug the battery and see how long those caps actually feed the amps.