compasitor?

[studdyhalllooser]

ok...i have wondered for a while what a compasitor is for "high end" car audio...all i have found is that it saves your battery. that dosn't tell me what is IS. anyone help?

[Munner]

I think you mean "capacitor". A capacitor basically stores a charge from the battery temporarily.

[studdyhalllooser]

would this stop my lights from dimming at night?

[biggc1]

caps suck upgrade your alternator first then get a second battery.

[studdyhalllooser]

caps may suck but they do seem like a MUCH cheeper alternative to upgrading my alternator and a new batery...how much you think for the upgrade on the alternator? i may be wrong

[glacius182]

Since when capacitor sucks? I've got one in my cars since I've upgrade to a really good audio system. It's like having a second battery, but a little smaller and because of this reason, you don't really need to upgrade your alternator. And when you are ready to upgrade your alternator, that means that you have an astounding audio system. And I'm telling you, I made 136.6dB with only 2 amps, I know what I'm talking about.

[aithanmier]

caps are the bears pizzle...get one, nuff said

[Guest]

yeah I have a Lightning Audio 1 Farad on my sub amp.. no dimming lights when it bumps..

[biggc1]

Since when capacitor sucks? I've got one in my cars since I've upgrade to a really good audio system. It's like having a second battery, but a little smaller and because of this reason, you don't really need to upgrade your alternator. And when you are ready to upgrade your alternator, that means that you have an astounding audio system. And I'm telling you, I made 136.6dB with only 2 amps, I know what I'm talking about.

Since you know what your talking about I assume you know that alot of people have seen a loss in db by adding a cap.

[aithanmier]

i'd be interested in finding out your sources on that problem, i have never heard of it...and as an electrician i don't see how it could happen.

[biggc1]

I just know from being around db drag Ive seen it.

[biggc1]

The Test System:

1x Ford Festiva Trio
1x JBL W15GTi subwoofer (DVC 6ohm, wired for 3ohm)
Street enclosure tuned to 48hz
1x JBL A1201GTi 1200WRMS Monoblock
2x SuperCharge Gold 900CCA batteries
1x Stock 60A alt.
1x 0g wiring harness
1x Lightening Audio Competition Series 1.0 Farad Cap
1x Alpine headunit (5V subout, unclipped)

Test Equipment:
1x DMM
1x Goldline DSP-30 RTA

Test Method:
Amp hooked up to CRO, gains adjusted @ 60hz until clipping, then backed off. LP Xovers set to 80hz using CRO & DMM.
Enclosure strapped Street Beater style, ports blocked by tail gate, filler pack in wheel well and false floor installed (this gear is normally removed for SPL).
Engine idling @ 800RPM. Tests run with voltage on amp terminals showing @ 14.1V idle.
15 minutes cool down between runs.
Run some tones, find the "mad note" @ 51hz and commence testing.

(Quick Note: This system doesn't suffer from typical power issues such as blinking headlamps at night.. its a stout power supply)

No Rear Battery, No Capacitor.
Voltage On Burp: 12.8V (1.3V Drop)
Output: 140.7dB, 140.7dB, 140.6dB

No Rear Battery, 1 Capacitor.
Voltage On Burp: 12.6V (1.5V Drop)
Output: 140.5dB, 140.4dB, 140.3dB

Both Batteries, No Capacitor.
Voltage On Burp: 13.8V (0.3V Drop)
Output: 141.0dB, 141.0dB, 140.9dB

Both Batteries, 1 Capacitor.
Voltage On Burp: 13.2V (1.2V Drop)
Output: 141.0dB, 141.0dB, 140.9dB

Make of this what you will.

Sound like a 2nd battery outweights using a cap.

In this case, the Cap rendered the systems performance despite the popular beleif that a battery's transfer is slow due to rinse time. Do with this info as you please. . . but if you plan on installing in a Stiffening Cap, you may want to consider a second battery.

It's a well known fact that capacitors don't help SPL readings in comp environments, and often (as this example shows) hinder it. Why? Becuase most caps are for transient power only. They give up their power before the meter even has a chance to read.

[glacius182]

Ok, first of all consider this, the advantage of adding a Cap is when your alternator isn't strong enough to push all the current you need for your amps. In your example, we clearly see that the alt is strong enough to drive your amps without anything else. Adding a second battery is useful when you have a monstruous system or when your wiring is too small or too long. I totally agree with your example, but for anyone who's not doing any SPL competition, a cap is the easiest, cheapest and fastest way to improve your current in a Festiva.

And for those who doesn't understand the little loss between nothing and adding the cap, it's pretty simple. That's because of the time needed to charge the cap. While charging the cap, the current is going more in the cap (easier to pass) then in the amp (harder to pass). That's why you lose some dBs.

[studdyhalllooser]

ok....i dont think its worth the money to buy a better alt and high end second battery to gain .7 db....you have to realy be into what your doing to realize that much of a db change. when my eyes cant focus on the road because they are physicaly being vibrated around by my music i think its time to turn it down a little :shock:

[biggc1]

It was a stock alternator and this was basicly the point of the article.


No Rear Battery, No Capacitor.
Voltage On Burp: 12.8V (1.3V Drop)
Output: 140.7dB, 140.7dB, 140.6dB

No Rear Battery, 1 Capacitor.
Voltage On Burp: 12.6V (1.5V Drop)
Output: 140.5dB, 140.4dB, 140.3dB

Loss of .2 to .3 db and the voltage actually dropped .2 volts lower with the cap.