help choosing a capacitor for my system?

iamfico · 06-02-2006, 10:42 PM

I have most of the stuff I'll be using to setup my system & I'll be done pretty soon, but I was wondering whether a 5 farad capacitor would be enough or should I pay a few more bucks for a 20 farad one

It will have a pretty decent sound system which would need a cap on its own but I just want to make sure the cap i get can handle the system and the PC

My setup:
P4 ATX PC w/400w power supply (uses about 300)
Xenarc in-dash touchscreen
2 JL 12W6 Subwoofers // powered by MA audio amp (500 rms to each@ 2 ohms)
JL 3 way component set & random rear speakers // powered by Alpine V12 (100 rms to each @ 4 ohms)

that pretty much covers it.... also these are the two i'm considering, if anyone has any other recommendations please let me know

20 Farad Cap
5 Farad Cap

also... just thought i'd throw this in @ the end cuz its not really worth makin another thread but um... would it be safe to use a 400w inverter with the PC since it has a 400w power supply? even though the actual power usage of the PC is only about 300w?

Jahntassa · 06-02-2006, 10:55 PM

Well, in theory you'd only need 2 farad for the subs. No real big point in putting a cap on everything else, just on the subs.

And you'd probably want a larger inverter.

iamfico · 06-02-2006, 11:34 PM

Quote: Originally Posted by Jahntassa

Well, in theory you'd only need 2 farad for the subs. No real big point in putting a cap on everything else, just on the subs.

And you'd probably want a larger inverter.

cool... just out of curiosity though, how do you figure out how many farads you would need?

also.... 1000w inverter sufficient?

Evilbunny1114 · 06-02-2006, 11:47 PM

i think its better to avoid inverters. but if u want to use 1 id go like 500 just incase

fooshizn1x · 06-03-2006, 12:11 AM

If your willing to put a 20 farad cap, why not just upgrade your battery and keep the old one as a second, put it on an isolator and have two batteries? That will be far superior to the capacitors.

Quote: Originally Posted by Jahntassa

Well, in theory you'd only need 2 farad for the subs. No real big point in putting a cap on everything else, just on the subs.

I have far less than his system and only a 1 farad cap (it was free) and it doesnt do jack in my setup.. I'm only 670RMS (per amp birthsheet 4Ohm x1 or 2Ohm x2) output by Sub amp.. and 1 50x4 (so like nothing) from the headunit.. I'd like to see where you'd got the idea for only 2 farad

Sidewalksalvage · 06-03-2006, 12:16 AM

Quote: Originally Posted by fooshizn1x

If your willing to put a 20 farad cap, why not just upgrade your battery and keep the old one as a second, put it on an isolator and have two batteries? That will be far superior to the capacitors.

I have far less than his system and only a 1 farad cap (it was free) and it doesnt do jack in my setup.. I'm only 670RMS output by Sub amp.. and 1 50x4 (so like nothing) from the headunit.. I'd like to see where you'd got the idea for only 2 farad

The general rule is 1 Farad per 1000w (peak) power you output to speakers or any high draw applicaton

The pc really isnt considered high draw, but subwoofer amplifiers are.

although a second battery will help the lenght of time you can run the system with the car off, it will not help reaction time of the subs. A capacitor will give you sharper cleaner bass and keep the power high on those continuous bass beats. A cap is used because the power can be pulled at a quicker speed than from the battery alone.

I run aproximatly 2000w on my subs and use a 2.0 farad capasitor, it works like a charm

5 Farad will probably be plenty of power, i think a 20 would be overkill.

fooshizn1x · 06-03-2006, 11:04 AM

sidewalksalvage: Do you have any proof to backup what your saying? I'm not saying its wrong, I just dont believe it until I see something to back it up.

Reverb_Lancer · 06-03-2006, 11:52 AM

Quote: Originally Posted by Sidewalksalvage

The general rule is 1 Farad per 1000w (peak) power

Normally the rule is 1 farad per 1000 watts RMS because amps never produce there rated peak power, its just a magical figure.

I would be looking to upgrade my battery to a deep cycle item like optima, also upgrade your ground wiring, alternator wiring and your power wiring depending on how large it is at the moment. That should be good enough to run all that.

If not simply add a second battery into your boot, i am running a dual battery system and it works perfectly. I am not a fan of caps, think they are more for wank/bling factor than anything else.

Sidewalksalvage · 06-04-2006, 06:59 PM

Quote: Originally Posted by fooshizn1x

sidewalksalvage: Do you have any proof to backup what your saying? I'm not saying its wrong, I just dont believe it until I see something to back it up.

WEll i dotn really know how you want me to back it up....

Lol...i agree they are a bit of a "bling factor" but with my system, which contains an old battery and the original alternator...etc, the cap helps alot. See without it, when the bass hits hard, all my lights dim and the video screen flicks. With the cap installed however, everything remains at even power.

Is it necessary to have a cap...no, if you have a proper alternator and better end battery, you probably dont need it, but it cant hurt.

blazinaspire · 06-04-2006, 11:09 PM

well i hear that caps are **** from some people and from others i hear that they are great, but i have never used one, but i have my stock alt ( around 48A ) and i have a crappy battery in the engine bay and i dotn even have an issolator with my second battery ( energizer ) and my 550WRMS amp is hitting very very well, its all in your battery man, my energizer battery keeps my voltage at 13.9V and my amp is ratted at 14V at 550wrms at bridged 4ohms ( fosgate amp ) and everything is great, afcourse my voltage goes down a bit when the deep bass hits ( down to 13V ) but thats ok because everything int he car is run at 12V so at night my lights dont even dim, so my advice is get yourself a better battery and upgrade your alt power wire and your grounds, this alone without a second battery helps a lot

scott_fx · 06-05-2006, 01:47 AM

I've heard the 1 farrad per 1000watts rule of thumb before but I've also heard that they do little for your system. The capacitor arguement isn't something i'm willing to get into but, I've read that most times anything under say 15 farrads is a waste of your money.

side note: I have a 1 farrad cap sitting in my room (got it for free with an amp i got) and have no plans on ever installing it.

i'd also recommend going with an optima battery and upgrading the big 3 before considering the cap

Caelric · 06-05-2006, 03:14 AM

Caps are a band aid, when what is usually needed is major surgery. They do a good job of masking the real problem, but the real problem still exists and will bite you in the *** at some point.

Oh, and yes, I do actually have a cap in my setup, it looks pretty cool, and has neat lights and a voltmeter. Thats about all it does, though.

Dave

RedGTiVR6 · 06-05-2006, 09:05 PM

heh - seems like most in here have already said it..caps are useless, UNLESS they are in the 3 farad + range

else, it's nothing more than bling factor, at which point, those who know audio, look at it and feel sorry that you waisted your money

spend your money upgrading the big 3 first.

if you STILL want to go with a cap (at least you're looking in the right size range for one, unlike most posurs), the 5 farad cap should be enough, but if it's only a few $$ more, 20 won't hurt at all.

one problem with caps is that sure, they provide power when needed, but then they have to recharge, granted it's lightning fast, but you're still down none-the-less

for a 20 farad cap to fully discharge, you have to be doing some heavy lifting, and that MA amp isn't going to come close.

Sidewalksalvage · 06-05-2006, 10:50 PM

So red, in your sistem, do you have any caps whatsoever?

Im re thinking my set up....

zzachattack2 · 06-06-2006, 03:37 AM

Sorry if im "hijacking" this thread, but how does a 20F cap go for just a little more $$$ than 1F caps? Is it all just hype? (I know that 20F is better than 2F, but i mean in this context is the extra capacitance necessary?)

One reason i suspect that is because from what I've seen, the higher quality companies don't manufacture huge zillion farad caps and stick to 1 or 2.

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