Power capacitors?

[jdawgg22 0]

i have heard a lot of bad things about capacitors.

and i know you may know more about them then i do

can you help me out?

[jonbearsmt 919]

lol dude.... ask a question

[johnecon2001 82]

Yes, I can help you out.

With what?

[jdawgg22 0]

idk

i just want to know if they acually help the sound of your system or not?

[ANeonRider 3]

Short answer, no.

[jonbearsmt 919]

IMO it kinda depends.. if you have an amp... and a small power wire.. if you run a cap and a fat wire from the cap to the amp it will help... but its only masking the problem........

if you have a BIG ASS power wire.... and you run a cap it will dogg the power... a battery is better to use.

caps suck.

Edited February 22, 2008 by bigjon

[sqguy 0]

Yeah, a cap is like a little battery. It helps a little but not really to make much change in sound you would hear. I'd say it helps your alternator survive more than anything, and it is kind of a bandaid for not enough power supply. Best use would be pushing a stock electrical system and trying to get by with it. If you are on the edge of power supply it may help, if you are way over what the car can produce you just plain don't have enough and it will not do much performance-wise. The cap just evens out the flow of power so if the flow is very plentiful or there is not enough flow to even out, then it does little.

I got one for $15 and going to put it on my stock car but I only will run < 1kw rms maybe < 700w, and just for daily music. IMHO I don't know anything "bad" about them or that they could hurt anything aside from careless discharge/etc. If your wire is large enough, another battery or larger alternator will do way more for you....but for $15 I'm going to use it. I also have a booster battery to try if that does not do enough; I'm trying to pair down the weight of my setup as well.

[shizzzon 461]

In terms of helping the sound out, they work best with unregulated power supplies. Regulated ones will try to output the same wattage at any voltage level. Unregulated outputs greater wattage at higher voltage levels.

Caps discharge very fast. Batteries may not discharge as fast as a cap can. I don't know if there is batts out there that can, maybe there is, i dont know.

However, caps are only to be used on an electrical system that already is capable of handling the load.

If your running 2000w of power and your car is striving to give you this power you want, a cap is only goin to help for about a few seconds until it's drained. After it's drained, if you're still playing music, you are not allowing the alt to recharge the cap since your electrical system is not strong enough.

The cap would then make it even worse, trust me, i've done this experiment.

Stock alt, stock batt - 2,400w audiobahn amp wired down to 0.5 ohms bridged!(never got a chance to measure output but it was a BIG difference compared to 1 ohm bridged) with 2 1F caps.

Voltage would dip from 14.2v down to 10.3v.

Removed caps, voltage would dip from 14.2v to 11.6v. Gotta have the power to charge before using caps. Luckily that amp wasn't a class d amp or i would of had some issues soon.

[jack 0]

Let me ask you guys this question, what if you ran a fat power wire to a dist block, from there; wire A goes directly from the d block 1 to a reversed d block (2) and wire B goes from the 1st d block to a 4 farad cap and then to d block 2 and then a single power wire runs from d block 2 to the amp. Then for the ground you do basically the same thing in reverse? This way the cap is available to discharge but not in the way of straight bat/alty power when it's empty. Do you think that will work better?

[jonbearsmt 919]

lol

[aznboi3644 2]

In terms of helping the sound out, they work best with unregulated power supplies. Regulated ones will try to output the same wattage at any voltage level. Unregulated outputs greater wattage at higher voltage levels.

Caps discharge very fast. Batteries may not discharge as fast as a cap can. I don't know if there is batts out there that can, maybe there is, i dont know.

However, caps are only to be used on an electrical system that already is capable of handling the load.

If your running 2000w of power and your car is striving to give you this power you want, a cap is only goin to help for about a few seconds until it's drained. After it's drained, if you're still playing music, you are not allowing the alt to recharge the cap since your electrical system is not strong enough.

The cap would then make it even worse, trust me, i've done this experiment.

Stock alt, stock batt - 2,400w audiobahn amp wired down to 0.5 ohms bridged!(never got a chance to measure output but it was a BIG difference compared to 1 ohm bridged) with 2 1F caps.

Voltage would dip from 14.2v down to 10.3v.

Removed caps, voltage would dip from 14.2v to 11.6v. Gotta have the power to charge before using caps. Luckily that amp wasn't a class d amp or i would of had some issues soon.

How long the cap lasts on a 2000 watt amp depends on the size of the cap...a 1F cap would be discharged in milliseconds which would do nothing

[patented17 21]

Basically a cap just adds to what your alt. has to recharge.

[jonbearsmt 919]

just get a normal car battery in the truck it will help you more then the caps

[Guest zedman]

I have never used an individual capacitor and I have no plans to start now. Just my opinion but it doesn't seem to help anything its more a gimmick than anything else. Z

[sqguy 0]

I had a 1f cap on my test bench in the power. I would turn off everything, just a HU using memory and displaying a clock. I'd pull the 12v and the HU would go for about 6 seconds and die.

[helotaxi 46]

Capacitance is measured in Farads. Current storage capacity is usually expressed in Amps times a unit of time. Car batteries and the like have their capacity expressed in amp*hours. Total capacity of a cap is one thing, but the usable charge is only that stored between the alt voltage (usually between 14.4V and 13.8V) and the battery voltage (about 12.6V). If you do the math, the usable capacity of a capacitor is on the order of 0.5 amp*seconds per Farad. That's also assuming a perfect world.

Let's say that we're in a perfect world. Alternators transition between current demands instantly and caps have no ESR. We have an alternator dedicated to the stereo that is 150A. We also have a 2.5kw amp and a 5F cap. The music that we have cued up has a decent bassline around 50hz. The cap will make up the difference (with a steady voltage drop) between the demand of the amp and the max capacity of the alt for a whole two cycles of that 50hz bassline, or 0.04 seconds, assuming 14.4V from the alt and 85% efficiency from the amp (both of those are pretty darn generous).

A huge cap and a small system might see stable voltage. However with a system that small, the need for any help with voltage stabilization is tiny and for the cost of a huge cap, you could get a good battery that will do the same thing for voltage and allow you to play the system with the car off and make the car eaiser to start.