Ok ill try to explain one by one. I dont care whether you agree or not and this will the last time i try to explain an alternator, battery and capasitor. Bear in mind i'm talking about general car charging system.
Alternator
is the heart of your charging system. It supply at 13-14.4v and he size determines the current supplied by the alternator. So let say a 1000w rms amp installed in a car. How many current needed by the amp to run at 1000w?? Well using ohm law it needs 77 amperes. Well if ou have 80 amp alternator can you run your amp at 1000w??? Yes and no. This is because alternator will first supply current to car electrical systm and battery and lastly to amplifier. How to determine you are running at full 1000w then use a multimeter and see how much current pass through your amp.
Battery
Battery is the second source of supply of the car electrical system. its main purpose is to start the engine when ignition is turn on and from there alternator will take over. It also helps to supply current when alternator cannot keep up. Like an alternator which create electrical charges ased on engine momentum, battery creates electrical charges based on chemical reaction. disadvantages of it is slow discharge rate. Battery runs at 12v so when engine is turn off amp will switch to 12V instead of 13v -14.4v
Capasitor
It acts like a bank storing electrical charges. The bigger the capasitor the more electrical charge it store. It has a fast discharge rate but a normal charging rate. It acts as "smoothen the bump" i.e when current pass through fall below its normal line capasitor will temporarily supply current until supply are back to normal. Most of the time capasitor are left idle. The disadvantage is capasitor has a relatively high ESR (Equivalent Series Resistance). There are even stiffening cap which sound convincing but compared to a nomal cap, stiffening cap has better cover with almost the same funtion.
ESR
What is Equivalent Series Resistance? It is basically a resistance exist in all electrical appliances even in cables. A 1 farad cap has a negligible ESR rate but the higher you go the higher the resistance is.
Cables
A cable is simply a means of transport of electrical charges/current from one sourc to another source. Read the water analogy from
www.bcae1.com. The thicker the cable the more current can tranfer in a period in a same period of time compared to thinner cables.
Cap vs Battery
According to the test conducted, A 1 farad cap has faster discharge rate compared to battery. But cap has a reputation of power burst means it only discharge less than 1 second and recharge around 11 seconds or more. The larger the cap the more time it needs to recharge. A good capacitor acts the same. Its just the recharge rate was a bit faster but still wont be fast enough to supply for a period of time. A good baterry (Optima Yellow top) has one the best discharge rate compared to all battery. Its discharge rate was not far behind, but it can supply current longer than any given cap (yes even 100 farad) until alternator current supply back to normal.
So here is my opinion.
1.If you want to upgrade your charging system without spending too much. Do the big three uprade. Get a 4 gauge or even a gauge cable and upgrade (do not change just add cables) from alternator -ve to chasisi, +ve to battery and -ve battery to body. Why do you want to change to a bigger power cable??? Read back the water analogy from www. bcae1.com
2. Change to a bigger battery as it may helps you to listen to music when car is idle or engine turn off. Ass a second baterry if your system eats up most of the alternator and 1st batery current supply.
3. The last resort is upgrade your altrnator or rewound it for high current alternator. This wont be easy as the whole car elctrical system may be affected as current suply may be higher. A relay and 2nd battery is needed and also the big 3 cables upgrade is also needed.
Here's the link as promised.
RF 50 Farad cap
http://www.rockfordfosgate.com/scripts/rightnow.cfg/php.exe/enduser/std_adp.php?p_sid=x6i*JVmh&p_lva=&p_faqid=417&p_created=1092178200&p_sp=cF9ncmlkc29ydD0mcF9yb3dfY250PTIzMCZwX3BhZ2U9MQ**&p_li=
The comment by RC
http://www.audiogroupforum.com/csforum/showthread.php?t=4045 (I lost the original thread but this one is ok)
The big 3 upgrade
http://www.audiogroupforum.com/csforum/showthread.php?t=5800
So any smartass out there want to proove me wrong and capasitor is better than battery or even better... cap makes your system different.... take the RC cap challenge and proove him wrong and win $5,000 if you havre the balls to do it. Otherwise be humble and go learn something.
cheers