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Thread: To Cap or not to Cap?

  1. #1
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    To Cap or not to Cap?

    Ok so I have read loads of post saying 'Power caps are useless' and 'ALWAYS USE A POWER CAP FOOL' (in the voice of Mr.T, of course) but can't actually find anything saying when a power cap should be used if at all.

    Anyways, I have two 12" subs in my car and when the cars idling and im close to a car in front I car see my headlights dipping with the bass (and my dash lights). Im not to bother about this at the moment because I will be getting a new car and two new subs soon anyway.

    My question is when should a power cap be use? What are the advantages and are they noticeable? And will it solve the headlight problem if it starts to do it again in my new car with the new set up?

    Cheers guys
    Come on Peugeot....I want to fill you with noise!

  2. #2
    FLAC sdashiki's Avatar
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    im sure the new cars alternator and battery would be a better test for your system.

    do ALOT more research on google about caps and their pros/cons.

    there are lots to both sides of the argument.

    IMO, to avoid an argument or spending tons more on an upgraded alternator, just add a second deep cycle dry cell battery to your setup. with an isolator of course.

    though, the quick n dirty is that if you go above 1000w, you need "something" added to your electrical. Whether its a cap, a battery or a new alternator.

    there is some math to be done, taking your alternators output AMPs and getting the # of watts it can produce, subtract your systems wattage needs, subtract a little bit for the A/C and cars electrical. if you are pulling more than the alternator can physically produce, your lights dim.
    (All done)
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  3. #3
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    Wiredwrx's Avatar
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    Quote Originally Posted by sdashiki View Post
    do ALOT more research on google about caps and their pros/cons.

    there are lots to both sides of the argument.
    Truer words are RARELY spoken/typed.

    Michael
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

  4. #4
    Car Audio Moderator durwood's Avatar
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    I am not going to argue this (again) but to make it easy since there is confusion...

    Extra Battery = More strain on an alternator -These are only good if you plan on running the stereo with the car off.

    Better Battery (Red top Optima or similar) = Ok may reduce strain on alternator and provide extra current more quickly when your alternator can't supply it. Better than stock battery.

    Upgraded Alternator = Supplies more current that you amps need. True fix, but expensive.

    Cap = Smooths out ripples in DC voltage from the regulator, but is not for fixing dimming lights.

    Proper wiring = less strain on equipment. It's good to make sure you are using the proper gauge of wire and the connections are secure. If you use 4 gauge going back to an amp, techncially you should add extra 4 gauge ground to battery/chassis and alternator to chassis.

    Search for the "Big 3" upgrade.

  5. #5
    FLAC sdashiki's Avatar
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    What you say is true, but doesnt the following scenario benefit the whole electrical system, alternator, carputer and car included;

    normal Die-Hard w/e car battery
    connected to
    isolator
    connected to
    yellow/red top Optima
    connected to
    audio/visual/carputer system

    once the 2nd battery is topped off (charged fully once) does it really put that much strain on an alternator? I can see how the slow drain from the A/V would pull current from the cars first battery and put strain on the alt. But is it really THAT bad? just curious.
    (All done)
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  6. #6
    Car Audio Moderator durwood's Avatar
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    Quote Originally Posted by sdashiki View Post
    What you say is true, but doesnt the following scenario benefit the whole electrical system, alternator, carputer and car included;

    normal Die-Hard w/e car battery
    connected to
    isolator
    connected to
    yellow/red top Optima
    connected to
    audio/visual/carputer system

    once the 2nd battery is topped off (charged fully once) does it really put that much strain on an alternator? I can see how the slow drain from the A/V would pull current from the cars first battery and put strain on the alt. But is it really THAT bad? just curious.
    The isolator is a good idea, but at some point you need to charge up that battery. However, if the alternator is trying to charge BOTH batteries, then it's an extra load on the alternator.

    Take a generator/motor and put a crank on it that you can spin, then connect up a light bulb and a battery similar to your car setup. Then turn the crank to get the light bulb to light up and feel the resistance of the motor generator. Next, add another battery in parallel with the first battery. Again, turn the crank on the generator/motor and then notice the resistance or how much force it take you to turn the crank. Its a pretty simple physics experiment to show what happens when adding extra batteries.
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