ok, I know the basics about them, they add power, save drain on battery, keep lights from dimming ect... But I want to know more. How exactly do they work, how do you hook them up, are there differnt size ones, like power wise, also are they worth the money, and would one help if I am running a 200watt pioneer amp to 6X9's and a rockford 360a2 to subs, any help is appreciated. Also pics would be helpful. Thanks

Go grab you a sandwich and something to drink because this might take you a few hours to read but once you do.....You'll know all you ever dreamed of about Caps.
Richard Clark on Capacitors

Im sorry man that is way too confusing for me. I need simple terms, what do they do, what are the sizes, and is it worth the money?? how do they hook up?

The fluids equivalent to a capacitor is an accumulator, such as a VERY small tank on the output of an air compressor which serves only to dampen pressure fluctuations in the air output.

The basic gist of Jobryan's referenced thread is that the contributions of a capacitor to the smoothness of the voltage present at the input terminal of the amplifiers is extremely small compared to the addition of more battery capacity and/or bigger wire from/to the amps. A battery holds MUCH more energy than a cap. Caps are not without usefullness- they are helpful in suppressing noise and higher frequency fluctuations in power wiring.

Capacitors are rated primarily by type, capacity and voltage.

Type in the use here would be electrolytic, the significance here being that they are polarity sensitive.

Capacity is rated in Farads, Microfarads and so on down in size.
A typical capacitor on a circuit board for power supply filtering would be in the microfarads (millionths of a farad) or tens of microfarads. A typical capacitor sold for car audio application is likely to be 1 farad to several farads.

Voltage rating should be higher than the highest likely voltage experienced by the cap.

As far as connection, a capacitor is hooked up in parallel with the amps power input.

Short answer, caps aren't going to hurt, but you are better off spending your money on battery capacity and wire. HTH.

In simple terms (and I can keep this in 6 words)

Keeps regular voltage running to amp.

Sizes?

Typical: 1 farad to every 1000watts.
Me: 1 farad to every 500watts.

How do they hook up?

Simple, negitive to ground (somewhere on body)
positive to power wire coming from battery

Is it worth the money?

Yes and no.

Yes if you want a cheap alternator alternative.
No if you want to spend a little more for a higher output alternator.

Hope this helps.

(If Im wrong correct me, im still learning as well)

EDIT: lol got to it before i did.