hey guys, i was just wondering, how many volts does a fully charged 1 farad cap hold, like when you put a volt-reader to it?

 

It depends on the voltage source that you use to charge the cap and the cap's voltage level.
If a cap is rated 1Fad at 16v and connected to a 12v source, it should read 12v. But if you use 24v source, there is a big chance that the cap will explose

 

Going along with this question...how/why do you charge a cap?...thanks

CL'S

 

I dont know how to answer the previous question.

how? A cap is charged when it's connected to a voltage source (in your car, it happens to be the batteries.)
why? A cap must be connected so it can do what it's supposed to do, right?

 

it's just that, i used a car battery charger to charge the cap, i hooked everything up right, and when the bass hits, the lights still dim, and the rpm's still waver around. i checked the cap with a volt reader, and it reads 13.8-14 volts, so i don't know what the problem is. is there a prob? isn't a cap supposed to eliminate lights dimming and shit?

 

Time for a high output alternator. BTW, you got to measure the voltage while your system is playing. If the lights are dimmed, I think the voltage level is more like 12.0v-12.5v

 

here, you might want to get one of these.... http://www.batcap.net/home.htm


I just picked up the Batcap 400

 

so, do i NEED a high output alternator? and how much do they go for?

 

This may be a dumb question but where in your power path do you have your cap wired and what type of amps are you running. Capacitors vary dramatically depending on type and percent error they are designed for. A 1 farad cap will cover most systems but If you have a ton of watts being pushed by your amps then 1 farad might not be enough. also a short in your grounding path can cause caps to not hold a charge or as mentioned above the dreaded cap explosion. A capacitor is a battery of sorts that filters out certain frequencies based on the farad rating, the concept is to give instantaneous power over and above your electrical systems capabilities during bass transients. You may very well have to go for the hi-po alternator but I would get a multimeter and check circuit integrity first.

 

I just saw your sig line. I would bet you have some other problem. Alpine v series amps(at least the 4by40) dont have the kind of current draw even in the worst bass transient to cause dimming unless your electrical system is bieng taxed somewhere else. A bad ground could very well be the culprit, or a loose power connection.

 

naw, i know its not the alpine amp, without a doubt its the rockford. and the ground is fine, i grounded just two inches from where i have the rockford amp grounded. anyways, with the hi-po alternator, how much $? how difficult is it to install? tthe cap is located about 8 inches from the amp, with the 4 gauge wire cut about 8 inches from the amp.

 

Either try an Optima battery or the 15 farad cap they have ou there (I forget the manufacturer). Before you give up and spend $$$on an alternator, start with the $200 yellow top battery

 

where would i go about getting a yellow top battery? and do i need to know a size, or buy a special tray or anything?

 

FYI,
http://www.dcbattery.com/optima2.html

 

mikeonay:
Damn lots of misinformation on here. Silverknight is right with everything he's said. So your lights are dimming and you have a cap. There are three possibilities...

1) Bad wiring
2) You need to stabilize the voltage with enough capacitance
3) You're not producing enough power

Now you can eliminate #3 if the total current draw is a good bit less...about 65%, of what you alternator runs at hot. If not...you will need a new alternator. I got mine from Ohio Generator...Tom and Gus are the two guys I spoke with. Lately it sounds like they're turning CL and TLers away though...I'll have to check on that.

If it's not #3, then it's probably #2. How large and what type of a capacitor do you have? And where is it wired and how (hopefully as close to the amps as possible and wired in parallel with a common ground).

If it's neither #3 or #2, it's #1. Make sure you sanded all around your common ground point, used large eyerings, soldered the connections to those rings, etc. Check to make sure you're using thick enough cable as well, and you may have to run a secondary ground off of the battery to the frame of the car.

Maybe I didn't read this but fill me in on exactly what you have in your car and how you have it all wired up.

And let me dispell two ideas here too...getting a larger battery will not fix ANY of the problems above. It's nice to have a larger, more powerful battery, but it won't produce power so if #3 is your problem it will do nothing. If #2 is your problem, batteries can not transfer enough power quickly enough to make up for this issue. And obviously it doesn't help #1.

Larger capacitors, such as the 15F type...may also not help any...because of such a high ESR not enough energy can be readily transferred in and out of these caps. You would be better off getting a bank of 4 or 6 very low ESR 1F caps than 1 15F cap.

Austin519

 

Take a look...

http://www.jacobselectronics.com/pro...o/caraudio.htm

 

C A P S S U C K

the only thing that caps really do is give more residual to your alterator for the A/C. Get a bigger alternator and another battery, and you can push a lot more watts without needing back up.

:P

 

DBO:
That's totally false man. Yes, you CAN add a big enough alternator to take care of any system. If you have an alternator that produces enough amps running idle as the system pulls at max...then yeah...you're fine. But take my system for example...it's pretty much impossible to upgrade my alternator further without investing thousands. And take the average guy's bass system that dims his lights. Bass systems may not need more than a cap because they don't constantly draw, thus a capacitor is an inexpensive yet quite effective alternative to something like upgrading your alternator. It's like saying capacitors are crap because you can plug your car into the wall outlet...yes, you CAN do that...but is it realistic or smart?

Also...when you upgrade from a small case to a large case alternator, for example...you're turning more copper mass and have a larger draw on the torque of the engine...and thus less HP. At the same time, you could add a $60 capacitor and eliminate that issue without any added trouble.

Austin519