No announcement yet.

Right size capacitor??

  • Filter
  • Time
  • Show
Clear All
new posts

  • Right size capacitor??

    Hi i just purchased this setup:

    a pair of 12" Sony Explod 1200W XS-L121PS subwoofers
    2-Channel Kenwood 800W KAC-7201 Amplifier

    I am wondering when i get it installed at Circuit City, if i will need to buy a capacitor also. If so, what size? I have a 1993 Dodge Dynasty and it has a new battery thats pretty big but im guessing that that doesnt matter, its all about the alternator. Any advice would be great. Thanks

  • #2
    Wait and see if you need it. To test, point your headlights at a wall and turn your music up to the maximum you're going to be listening at (not the maximum that it will go ). If the headlights dim to the beat, you could use a cap.


    • #3
      The rule is for every 1 thousand watts, you need 1 farad. So since you're pullin' 800. You can go with a 1 farad cap.


      • #4
        you guys are spreading mis-information. There are many different options that you should try before wasting money on a cap. First of all, you can upgrade what is called you magic three which will allow more power to flow through to stock power cables(get more amps from your alternator) and your second option is to get a new alternator that supplies more amps. Lastly, another option is to get a extra battery. Allof these things are much better options then a cap. A cap is considered a band-aid and most people that understand this realize that a cap should not be used.


        • #5
          A cap will fix the headlight problem. I'm sure there are a few ways to fix it, but I'm sure a cap would be cheaper than a new alternator and battery.


          • #6
            get a battery first or what is cheaper for you
            2005 Pontiac G6
            Headunit: AVH-P3100DVD
            Front speakers:Infinity 6022i
            Rear speakers: Powerbass pb-b6.5xv.2
            Battery: top of line walmart brand(LOL)
            Wiring: 1 run of 0 ga
            Amp: MTX JH600 & Lightning Audio B300.4
            Sub: TS-W2000SPL


            • #7
              Just because a cap is a 'band-aid' solution doesn't mean it's horrible and nobody should do it. I put a cap in my car because I didn't have the money at the time to upgrade everything else. A cap will do fine to keep things from 'dimming'.

              Later, start replacing stock wiring with better stuff, and get a better battery (in terms of cost), getting a better alternator is fairly pricey, and it's usually a bit of a pain to add a second battery for a beginner.

              Saying that using a cap is 'Mis-information' is kinda weak. You can use a cap if all you want to do is have some extra sound and not destroy your electrical system, especially if you don't want to start throwing money at the car.


              • #8
                Saying that using a cap is 'Mis-information' is kinda weak. You can use a cap if all you want to do is have some extra sound and not destroy your electrical system, especially if you don't want to start throwing money at the car.
                Caps are (IMO) a waste of space - they actually put more load on your electrical system because there's yet another thing to keep charged up, and tests have shown that they don't noticably improve SPL or SQ. They're very heavily marketed because manufacturers (and indirectly, the magazines that review their products) make a huge profit on them, more than most other ICE equipment (a 1F cap can be bought for 20, badged up as PG, RF etc, and sold for ~100). Serious SPL competitors don't use caps for a reason

                Upgrading your stock cabling under the bonnet is cheaper than a cap, not difficult, and actually does something useful! Failing that, an uprated (or even second) battery is the way to go, but in "Emerica2843"s case, 1 800w (probably peak watts) amp won't need anything like this - a decent power cable to it should be sufficient, without changing anything else under the bonnet.

                If you're interested, post 8 in the link below (which itself was borrowed from will give you all the physics behind why caps are just a useless tin can -


                • #9
                  But caps will keep his lights from dimming to the beat. And I would like to see your source that says that caps put and large load on the electrical system.
                  2007 Honda Fit Sport 1.5L SOHC-VTEC


                  • #10
                    I always hate these cap debates by people who for the most part either don't understand how the cap works, or just vomit up stuff they have read other places on the internet by other stupid people.

                    A cap is not a band-aid, but it will not solve all problems.

                    If your electrical system can not keep up with the demand of the system, a cap will HURT you more than it helps. Remember, your alt rating is not for idle, it is at peak (usualy ~1500-2500 RPM) so just because you have a 100 amp alt, doesn't mean you are getting 100 amps while you're sitting in a parking lot running your engine. Make sure your electrical system can keep up.

                    If you have checked and you are producing enough power, a cap may help you if you have brief dimming or "pulsing light" problems. Your battery is not designed for instant discharges, there is a slight delay from the demand and the supply. And while your car is running, almost all of the power is coming from the Alt. Once again, there is a delay from the demand till your alt has time to respond to the increased draw. The cap stores electricity to rapidly discharge in the short delay from demand to supply.

                    A cap is also a good idea to help clean up your cars power to a carputer. Most people don't think about it but it does assist in eliminating some of the brief dips and peaks.
                    Causa latet vis est notissima

                    VIA SP13000
                    1GB DDR400
                    Slimline Slot-load DVD-RW
                    60GB 2.5 Inch SATA 5400RPM
                    Dual Active PCI riser
                    PCI TV/FM card
                    Logisys FP800
                    Thermaltake VFD Media Lab


                    • #11
                      No you dont need one. (simple).
                      Cap is 90% of time waste of money.
                      mushin had the best idea, which if u do i doubt you'll see dimming.
                      And if you do upgrade the "big 3".

                      But really. you install it, dont have them do it.
                      Core duo
                      1tb harddrive
                      256 ddr
                      8 lilliput

                      still installing...


                      • #12
                        hey guys thanks for all the replies. well today my car pretty much died Im pretty sure its the starter because the engine doesnt crank at all. Would this have anything to do with the subs/amp/electircal wiring of the car? If anyone could help, you could instant message me on any one of my screen names? Thanks