Hi. Just curious what size (how many farads) capacitor I should get for my stereo I am putting together/adding onto. I already have a higher output (135 amp) alternator, I will be getting an Optima red top battery. Don't need an extra battery, because I will not be playing the system with my car turned off really. Anyway, I have 4 amps (3 for subs, 1 for components), with a total of about 2500 watts RMS. I figured a 3 farad cap should be fine, but I called a local shop and they recommended a 5 farad. Is this overkill? Would a 3 farad cap be sufficient.
Thanks
PS - This is the cap I had in mind: http://cgi.ebay.com/ws/eBayISA...&rd=1

 

have you installed the system, have you upgraded all of the underhood wiring, does it dim today....

I wouldn't consider any additional equipment until you can answer those three questions with a yes...

 

1 farad per 500 watts RMS will be good.

 

no the system is not installed yet, i would like to get this all figured out b4 i install it. i was told my a local shop to go w/ a 5 farad cap, but i had figured 3 was sufficient

 

3 is sufficiant, but the 5 farad will ensure long battery and alternator life...if you have the funds available get the 5 farad but the 3 shouldn't harm it

 

if you want good value, look at the power acoustik 20 farad cap. i got mine for 149 from a local ditributor in richmond va and its performance has been amazing. i know it sucks to have power acoustik in your car ( i have all diamond audio amps and speakers, eclipse 8454 series head unit) but even if it only does half of the claimed 20 farads its a great value

 

1. you need to search!!!
2. you need to search your own threads...we answered this already!
https://honda-tech.com/zerothread?id=880885

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Robert Nesta &raquo;</TD></TR><TR><TD CLASS="quote">1 farad per 500 watts RMS will be good. </TD></TR></TABLE>
it's actually 1 farad per every 1000 watts

 

get a dry cell battery and wire it in, in the trunk! nothing beats having a dry cell wired up as a second battery when it comes to systems that pull lots of power.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2ndchancehonda &raquo;</TD></TR><TR><TD CLASS="quote">get a dry cell battery and wire it in, in the trunk! nothing beats having a dry cell wired up as a second battery when it comes to systems that pull lots of power. </TD></TR></TABLE>
^^^^^^

 

how difficult is adding a second battery? is an optima yellow top good?

 

super easy just run the power wire from the main power source(under the hood) to the extra power source(in the trunk) then to the amp...I dont know if you have to put another fuse in line though I'll try to find out...
Then with the grounds you can run them right to the negative battery terminal.

 

hmmm, wouldn't that make the cars electrical system 24 volts though?

 

A battery cannot perform the same function as a cap. It relies on a chemical reaction that doesn't react fast enough.

BTW, if you are going to put in a second battery for another reason, you NEED an isolator or you will kill one or both of the batteries in short order.

 

I would have a cap and a secondary battery. I am trying to figure out how I would add an additional battery (isolator, etc.).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rochesterricer &raquo;</TD></TR><TR><TD CLASS="quote">A battery cannot perform the same function as a cap. It relies on a chemical reaction that doesn't react fast enough.

BTW, if you are going to put in a second battery for another reason, you NEED an isolator or you will kill one or both of the batteries in short order.</TD></TR></TABLE>
A battery will perform better than a cap. You do not need an ioslator and your system will not run at 24V. I had an extra battery in my trunk for 6 months, sold the system and bought a new car...took the battery out of my trunk and put it into the new car and works perfect.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by puddz27 &raquo;</TD></TR><TR><TD CLASS="quote">...I dont know if you have to put another fuse in line though I'll try to find out...</TD></TR></TABLE>
You should put another fuse after the 2nd battery and between batteries, in my set up I only put one B4 the second battery.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by puddz27 &raquo;</TD></TR><TR><TD CLASS="quote">
You do not need an ioslator</TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by puddz27 &raquo;</TD></TR><TR><TD CLASS="quote">A battery will perform better than a cap. You do not need an ioslator and your system will not run at 24V. I had an extra battery in my trunk for 6 months, sold the system and bought a new car...took the battery out of my trunk and put it into the new car and works perfect.

You should put another fuse after the 2nd battery and between batteries, in my set up I only put one B4 the second battery.</TD></TR></TABLE>

You can do what ever you want, but I know 3 people that did this and they had dead batteries inside 3 months. You may just be lucky.

They're headlights stilled dimmed as well. The batteries just couldn't react fast enough.

You might also want to keep in mind that a second battery places a greater load on the charging system, so it may end up killing your alternator as well.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CrazyModGSR &raquo;</TD></TR><TR><TD CLASS="quote">I would have a cap and a secondary battery. I am trying to figure out how I would add an additional battery (isolator, etc.).</TD></TR></TABLE>
So your saying you want to stress your alternator more and provide less current to your system by putting in the second battery.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxxtreme &raquo;</TD></TR><TR><TD CLASS="quote">So your saying you want to stress your alternator more and provide less current to your system by putting in the second battery. </TD></TR></TABLE>

Exactly what I was trying to say.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rochesterricer &raquo;</TD></TR><TR><TD CLASS="quote">You might also want to keep in mind that a second battery places a greater load on the charging system, so it may end up killing your alternator as well.</TD></TR></TABLE>

exactly

 

There is a little misconception about caps and batteries here.
Capacitors help to keep voltage high at peak demand. Batteries help to keep amperage more steady and requires an upgrade in the charging system or additional charging systems. That's why capacitor do a better job when eliminating light dimming at high power applications. You can do a combination of them to achieve an optimun performance but, it requires planning and some $$.

 

so...basically don't add another batteryif you don't upgrade the alt and you don't need a cap if you have a second battery and upgraded alt

so a cap is a good adition to a syatem like mine thats running on a small battery

 

Even with a high output alternator, a cap is a good idea. As I and others have stated a battery does not perform the function of a cap. That may have gotten confused in all of this.

 

Get the cap, get the batt. you already have the alt. use solinoid to isolate [Use 2 of the same batt. new] paralleled batts stay 12 volts, place fuse [ 200 amp anl] within 18" of rear batt.and at sol. up front, use 4ga wire from sol. to rear batt. trigger sol. with ign. hope this helps. 94