I got a cap from a buddy of mine who said it was already charged from him using it. Currently I'm running a 400watt system and after I put the cap in and wired it up, it still draws from the altinator. Could this be that the cap needs to be charged, or what is it?

 

Well, that guy no absolutely nothing. What he said is entirely incorrect.

Capacitors are useless, they are a waste of money. They are a band-aid for a weak electrical system and they create ANOTHER load on an already stressed electrical system.

The correct way to stabilize/upgrade you electrical system is:
1) Upgrade the Big 3
Use 4awg or 1/0 awg and add the following three wires:
Alternator Positive lead tot he positive battery post
Negative battery post to the engine block ground
Negative battery post to the Chassis Groung
2) Replace you're stock battery with and Optima Red top, or if under severe load...replace with an Optima Yellow Top
3) Upgrade your alternator, if you can afford this at first...do it first...
If not, when you complete steps 1 and 2 and you still have electrical problems...look into a new HighOutput Alternator.
I suggest:
www.excessiveamperage.com
www.mean-green.com

NG

 

A capacitor does not need to be "charged". It gets its charge from the electrical circuit it is in. And it will get its electrical power from the altenator because that is where the battery gets its power while recharging when car is on, so when the capacitor is hooked up to the battery it will also draw current from the alternator.

Also if your friend handed you the cap charged and you touched the terminals, you would have had a nice jolt.

 

didn't touch the terminals, due to that jolting fear.

 

Ahem

NG

 

did he use a resistor to convert the ohms in the charge when he used it??.. i dunno.. i mean i have saw caps do good on some situations.. but if your having big problems upgrade the stuff mentioned above.

 

Like most of the other post generally state. Caps are used for transisitional spike (bass hits). Caps are energy storage devices and are charged when there is a surplus of charge. If the stereo system is draining most the charge then the cap turns into another load. They will help on a system that things like headlights MODERATELY dimming on bass hits on idle. If the lights dim when the engine is above 2000prm then they are hurting more then helping.

There is an old trick that we used to do is charge a small cap and then tell someone to catch and the oil in their hands would discharge it and give them a lil shock. Those were nowhere near the 1 farad size of the ones used in audio systems. To properly discharge a cap prior to removal, is to use the resistor that comes with the cap in shipping. I have seen a guy not do this and arc welded an allen head screwdriver when he hit chassis while uncrewing the termial on the cap to remove it.

When you see a fuse on an amp, it is for max draw to protect the amp. When you have multiple amps there is fuses on the amp and a larger fuse on the lead that hooks up to the battery. That fuse is incase the power lead somehow gets grounded to the chassis by wire rubbing or melting. Electricity follows the path of least resistance. So the large fuse will blow and not allow the battery to be be connected to the ground. It would be like taking a wrench and laying across the battery leads. The large fuse should be within 12" of the battery terminal if I remember correctly. On some power distribution blocks have fuses also. The more fuses you have inline to an amp the better the protection level you have. If you install an block without fuses you are counting on the amp fuse to protect the amp. The fuses will blow in order of installation depending on the location of the over draw. Say the typical fuse system is 100A fuse at the battery, 30A at the distribution block and 15A on the amp. If the short is inbetwen the batttery and the block the 100A will blow. If the short is after the block then the 30A will blow and maybe the 100A will blow depending on how fast the 30A blows. Now if the amp draws more than 15A because of a sudden bass hit, then the 15A will blow. Now to go with wire guage. You have to match the wire to size of the draw otherwise the wire will act like a "fuseable" link. If you have, lets say, a 50A draw on a wire that is rated at 30A, you will either see a big spark and see a 2 piece wire or melt the insulation and then the wire will contact ground. This is how heaters work, controlled draw through wires to generate heat.

Yes they are a bandaid, but for smaller systems that need just a lil help, they are not totally useless. The best solution is the bigger alternator and wiring etc like ngsm13 stated.