[06racestang]

i have a 1800 watt amp and 2 1000 watt subs and was tryen to find out what size of capacitor i would need

[coolwaterblvd]

A batt cap would be more than adequate, but a single 1.5 farad one will be ok with a good 180 amp alt or 200. Make sure u upgrade all wireing going to the alt, and ground no smaller than 4 Gage, 1 Gage if u can esp with a high amt alt. I have to stress NO UNDER DRIVE PULLEYS WITH A BIG STEREO SYSTEM you will have nothing but problems.

[BigKevo]

A 1.5-2 farad should be enough for your system. Just a word of advice make sure to follow the instructions when connecting the capacitor to the battery. Use a resistor or test light across the fuse block(befor the fuses are installed!) to restrict the electrical flow into the cap. Failure to use a resistor\test light WILL result in arc flash and damage to terminals ect.

[ESG-642T]

Looks good, waste of money though.

What amplifier is this? Is it a true 1800 watts RMS or does it just advertise 1800 watts and put out 400?

[waldo2824]

x2. Doesn't really do anything. Just looks good.

[06racestang]

its a rockford fosgate p600

[06racestang]

it looks like it just advertises 1800

[BigKevo]

What is a waste? You cant be talking about a cap. A Rockford Fosgate p600 amp outputs 325 watts (RMS) X 1 @4 ohms, or 600 watts (RMS) X 1 @ 2 ohms. A amplifier of this size can draw up 96 amps of current. Most stock alternators provide around 60 amps. Do the math, your charging system cannot keep up the demand. Sure your battery helps but your sound quality quickly fades due to the lack of current supplied to your amp. This condition is refered to as "mudding" and can lead to amp & speaker damage. A simple way to test is by starting your car and cranking your system, if your head lights dim when the bass hits you are "Mudding" and you need more current. A Capicitor is essentially just a mass power storage device than can store and release power instantly(much quicker than a battery). I purchased my 1.5 farad cap @ Fry's electronics for $20, well worth it.

[Storkdork]

+1 Well said. Get a cap... NO smaller than a 1 Farad.

[gunz4me]

Truth be told, I would purchase an isolator and add a second battery to my car audio system before I would go with a capacitor! Long ago in a land far, far away, this is how I used to do ALL my car audio set ups.

I tried the capacitor hype in 1999-2000 and it didn't help anywhere near as much as a second battery/alternator isolator does! Let's just say with 1,000 watts RMS, my lights still dimmed with a capacitor whereas with way more power and a second battery, I had no such problems!

ETA: I have also read the myth that a car audio capacitor will not explode, even if wired improperly. I have personally seen the aftermath of one of those 2 farad capacitors exploding will do, and it was not pretty! One of the car audio shops used to keep those photos handy to show the quality of a competing audio shop's work.

[06racestang]

which would be better running 2 batteries or will the cap do the job for wut i need

[ESG-642T]

Originally Posted by BigKevo

What is a waste? You cant be talking about a cap. A Rockford Fosgate p600 amp outputs 325 watts (RMS) X 1 @4 ohms, or 600 watts (RMS) X 1 @ 2 ohms. A amplifier of this size can draw up 96 amps of current. Most stock alternators provide around 60 amps. Do the math, your charging system cannot keep up the demand. Sure your battery helps but your sound quality quickly fades due to the lack of current supplied to your amp. This condition is refered to as "mudding" and can lead to amp & speaker damage. A simple way to test is by starting your car and cranking your system, if your head lights dim when the bass hits you are "Mudding" and you need more current. A Capicitor is essentially just a mass power storage device than can store and release power instantly(much quicker than a battery). I purchased my 1.5 farad cap @ Fry's electronics for $20, well worth it.

A capacitor is a waste in any decent audio setup, its why the big boys have 10-15 extra batteries instead of 500 capacitors.

Originally Posted by gunz4me

Truth be told, I would purchase an isolator and add a second battery to my car audio system before I would go with a capacitor! Long ago in a land far, far away, this is how I used to do ALL my car audio set ups.

I tried the capacitor hype in 1999-2000 and it didn't help anywhere near as much as a second battery/alternator isolator does! Let's just say with 1,000 watts RMS, my lights still dimmed with a capacitor whereas with way more power and a second battery, I had no such problems!

ETA: I have also read the myth that a car audio capacitor will not explode, even if wired improperly. I have personally seen the aftermath of one of those 2 farad capacitors exploding will do, and it was not pretty! One of the car audio shops used to keep those photos handy to show the quality of a competing audio shop's work.

Smart man. 2nd battery before you waste money on a cap any day of the week.

[BigKevo]

Originally Posted by 06racestang

which would be better running 2 batteries or will the cap do the job for wut i need

We drive Mustangs right? Batteries are much heavier & larger than caps. Considering the size of your planned system there is no need to add a battery UNLESS you want to extend your play time when the car is not running. High current alternators reduce hp, again considering its a Mustang and your plans I dont feel its necessary. A Cap will do you fine. Yes caps can be dangerous hence my first post. Treat it right, read the instructions. Yes Competition setups utilize battery banks and high current alternators(and for good reasons) but I would not load up my stang with all this just to run a Rockford Fosgat p600 amp and two subs.

[ESG-642T]

Originally Posted by BigKevo

We drive Mustangs right? Batteries are much heavier & larger than caps. Considering the size of your planned system there is no need to add a battery UNLESS you want to extend your play time when the car is not running. High current alternators reduce hp, again considering its a Mustang and your plans I dont feel its necessary. A Cap will do you fine. Yes caps can be dangerous hence my first post. Treat it right, read the instructions. Yes Competition setups utilize battery banks and high current alternators(and for good reasons) but I would not load up my stang with all this just to run a Rockford Fosgat p600 amp and two subs.

Nor is their a point of wasting money on a capacitor.

[BigKevo]

Please explain why a $20 cap is a waste. Plain and simple Caps work. They do what they claim to do,release stored energy when current draw exceeds the charging systems supply. Pretty simple to understand. They have been widely tested\proven and are used to solve current draw issues in all sorts of electrical equipment. As a electrical engineer I guess that is something I can respect. Of course extra batteries and bigger alternators work also. The question is does he really need them? IMO NO. I got four batteries and a 180amp alternator on my boat equipped with 4 JL 12w6v2. But guess what I don't plan on sitting around for hours(with engine off) listening to my Mustang like I do my boat. I push two JL 10w3v3 in my car @ 600watts true rms with no problems thanks to my cap. I have taken voltage and current measurements and guess what it solved my current issues. For me proofs in the pudding.