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Does my car have enough "power"?

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  • Does my car have enough "power"?

    Hey guys,

    I have a 2004 Honda Civic EX and I was curious wether or not my car has enough power to run the components I want.

    I noticed that if I am in neutral with my lights on bright my lights will "brighten" when I give it some gas. This is barley noticeable but leads me to this question.

    I plan on running a carputer with one of the higher OPUS power supplies (180w?). I also plan on having 1 amp running my existing speakers and another running maybe 1 or 2 10-12" subs (not sure yet... im not looking for a lot of power). I will also be installing an EQ.

    What do ya think? I don't want to put a lot of stress on my battery and alternator. What are my options? Don't the make sure sort of large capacitors just for this problem?

    Thanx in advance!

  • #2
    Moved out of the FAQ Emporium.
    Don't post there unless you have an infomrational post to share.

    Opus doesnt make a 180w PSU.


    Since your lights brighten when you hit the gas, it indicates the battery may be flat, since the alternator kicking in provides more power.

    If you take the battery to AutoZone or O'Reilley or any other major auto parts chain, they'll test it for free.
    Have you looked in the FAQ yet?
    How about the Wiki?



    Under normal circumstances, a signature would go here.

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    • #3
      Woops sorry,

      If admin could move it I would be appreciative.

      I had my battery tested and its perfect, the Honda dealer also said this was normal.

      Comment


      • #4
        my 01 civic powers a 200 watt opus, a 1600 watt (max) audiobahn amp, a 50 watt 3 way crossover, and a 400 watt alpine amp.

        I can't say how well your battery will take it, because i upgraded mine to a optima yellow top, but i can say that my alternator takes the strain fine.

        I would also advise against a capacitor, you could try the "big three" upgrade. Search the forums for it.
        REBUILDING!!

        Comment


        • #5
          Why would you suggest against getting a capacitor? Aren't they supposed to help maintain a level voltage and provide protection against suddens surges or dips.
          Avengerki
          PC Install: 85%
          Car PC: Revo-Sys X300 Double Din: 1.3GHz Pentium
          Software install and setup: 35%
          Entertainment Package: 85%

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          • #6
            Yes, I would recommend against purchasing a capacitor. Many people see them to be "band-aids" myself included. What makes you think you need one?

            heres a link to the "big three" upgrade: http://forum.sounddomain.com/forum/u...=5;t=007801;p=
            REBUILDING!!

            Comment


            • #7
              For me I dont really see the need although I have thought about it. But then I've also put a higher output altenator in my car and keep contemplating doing a dual battery setup with a capacitor tossed in for line conditioning. But I know I tend to overkill the power side but I also always look at what I might use in the future and try to prevent having to upgrade something I just installed a month ago. And I have also done the top-three that you mentioned.

              Edit: Personally I wouldn't be using the capacitor as a band-aid so much as an insurance policy against a sudden surge.
              Avengerki
              PC Install: 85%
              Car PC: Revo-Sys X300 Double Din: 1.3GHz Pentium
              Software install and setup: 35%
              Entertainment Package: 85%

              Comment


              • #8
                well... i expect Shadow to weigh in any day on this, but I'll give my thoughts on the matter... capacitors I think people look at with too narrow a scope. All anyone really sees is the issue of "can it support my massive subwoofer when my alternator/battery can't?". The answer to that is invariably no. You have to remember that for every watt you get out of that cap, you have to put another watt, plus efficiency losses back in. So if your power supply is insufficient to begin with, a capacitor just delays the inevitable.

                So what the heck good IS a capacitor then? Think in terms of the system-wide effects. Amplifiers generally perform best and coolest when supplied with ample voltage. Usually manufacturers bench test and rate their amps with a 14.4v regulated power supply. Compared to our cars, this power is awfully clean and devoid of any of the fluctuations in voltage imposed by other devices like defrosters, headlights, wiper motors, fuel pumps... A capacitor can help smooth out or eliminate these fluctuations PROVIDED that your alternator is supplying adequate current for all your devices.

                So do the math, if your amplifiers are 50 percent efficient, and you go somewhat conservative on RMS power and get 50x4+500x1. 200+500 watts at 50% efficiency means you could conceivably be drawing 1400w which at 13.8V (assuming your alternator maintained that voltage), is over 100 amps. I am reasonably certain that your average import passenger car is not going to supply you with much more than 80 amps... and remember, that's gotta run the car and all it's accessories too.

                So how do you get around the power problem? You've got at least two possibilities:

                1. You muscle through it. You buy a 170 amp alternator for $600+ and then start spending $1+ per foot of 0-gauge wiring which you have to somehow run under your car or cram under your carpet, not to mention all the wiring under the hood you'll have to replace so that the new alternator can deliver that kind of current without burning wires... plus the cost of whatever amplifiers you get.

                2. You plan for efficiency. First thing to check out is whom you would like to buy a full-range class-D amplifier from. Traditionally, class-D amplifiers have been unable to cleanly reproduce high-frequency sound, but there are a few companies, including Bang & Olufsen who produce high-end, high efficiency full range class-D amplifiers. These are typically 85-95 percent efficient. So, we'll take mine for example since i know it's specs off the top of my head: 50x5+300x1. That's 500w for 4 speakers and a sub. At 95% efficiency i'm going to be drawing about 38 amps at full tilt. My alternator produces a maximum of 80 amps, and the car takes about 40 of that. Cutting it close for sure but then the music isn't cranked to 11 on every dial either. At the levels i'm comfortable listening to, i'm only drawing about 6 amps. That sort of thing won't even phase your stock alternator.

                The next thing if you're adding a subwoofer is to pay attention to it's sensitivity rating. Manufacturers have various methods of arriving at this number, so don't take it as gospel, but it can help in determining which speakers can produce the most volume for the power you are giving it. Again, the louder your system sounds at a particular volume level, the easier you're likely to go on the amps.

                So back to capacitors, what good are they? Well again, maintaining voltage is key. Lets assume for a moment that your alternator can handle the complete electrical needs of your audio and vehicular systems. The mere act of turning on a device will create a voltage drop, drawing sometimes twice as much current as it's rated for for an instant. An appropriately rated capacitor can temporarily supply your entire electrical system with additional power to maintain that constant voltage, rather than succumb to a voltage drop. Voltage drops do two things, and the extent of which depend on the severity of the drop, but your lights may dim, and your sound quality may suffer. This is what capacitors are good for.

                So to sum up that longwinded rant: capacitors are NOT a power generating device. if your alternator can't keep up with your amps, a capacitor, no matter how big, will not help. Think efficiency before just strapping on bigger batteries and alternators. Because if your alternator CAN supply the power you need, then a capacitor will do just the trick to help you get the most out of your amps.
                Et ipsa scientia potestas est.

                Worklog for my 2007 Civic Si ...f*** it...
                Pictures of the Corolla (retired)here
                Need to make something? Here are a few ideas.

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                • #9
                  Thank you for the replies, special thanks to GoHybrid for being so in depth.

                  I belive the car will take the carputer just fine and depending on the sub I install I belive I will go ahead and do the "Big 3".

                  Another question for ya, is there any difference in Power Blocks? Brand, things to look out for?? They just seem like a simple way to distribute power and in a efficent way with fuses.

                  Thanks again!

                  Comment


                  • #10
                    power distribution blocks are definitely convenient. brand doesn't really matter. all you're buying is a fancy gold or chrome plated chunk of metal... maybe fuses come with it, maybe not. Just make sure that it is rated to handle all the various wire gauges you will be using, that it has enough terminals, and that it comes with some sort of cover (and why wouldn't it?!) to protect it from whatever might land on it and cause it to short.
                    Et ipsa scientia potestas est.

                    Worklog for my 2007 Civic Si ...f*** it...
                    Pictures of the Corolla (retired)here
                    Need to make something? Here are a few ideas.

                    Comment


                    • #11
                      hey gohybrid, nice to see someone else who actually knows how to use a cap & gives it credit for what it is...

                      my simplest analogy is a cap is to your electrical system, what a shock absorber is to your suspension... it won't take the place, or make up for a spring that can't suspend your car, but it will help control the constant hits....

                      everytime a cap is mentioned a bunch jumps in saying there worthless, usually acompanied by a few links from so called "experts" to validate there claim... but caps do have there place, & are not as much of a bandade as it is an assistant, & can some times help a borderline situation to the point that it can be adiquate...
                      MY NEWEST INSTALL:modded infiniti fx with big screen

                      first windows carpc install........my liquid cooled LVDS screen :D

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                      • #12
                        turbocad6,

                        Thank you for replying to my post... Before I joined I read your through your entire thread on your carputer and liquid lcd... Amazing. Keep up the good work.

                        Comment


                        • #13
                          thanks turbocad6. you know, one thing i never did was figure out exactly how much capacitance is really needed to stabilize voltage in a car environment. I can't imagine it's that much unless you're really beating the snot out of your system. I have a 1.2F cap that conveniently came with all my wiring, so i figured what the hell, i'll use it. The only time I ever see it discharging is when the starter motor is pulling on it. Not even with the stereo at full blast. I assume it's doing it's job well. But that's a small cap as car audio goes and I think it's excessive for my car. I go to the local audio shop and find these 20F and 50F cap arrays... I wonder if they're trying to reverse the earth's rotation with that or what...

                          do you have any idea or rough formulas for figuring out how much capacitance or "shock absorption" you really need?
                          Et ipsa scientia potestas est.

                          Worklog for my 2007 Civic Si ...f*** it...
                          Pictures of the Corolla (retired)here
                          Need to make something? Here are a few ideas.

                          Comment


                          • #14
                            a generally accepted rule of thumb is at least 1f for every 1,000 watts, but more can't hurt, & can help to a point... that doesn't mean that you'll see any add'l benifit by over doing it though..., & past a certain point there is no benifit...

                            truth is there are a lot of variables past just the wattage of your system, I usually go with a bit more, my last 1,200 watt system had a 5f cap, which was a bit too much, but doesn't hurt anything... half that would have done it for sure.... there are also a few different cap technologies available, I used an alumapro small square one that starts at 5f...
                            MY NEWEST INSTALL:modded infiniti fx with big screen

                            first windows carpc install........my liquid cooled LVDS screen :D

                            Comment


                            • #15
                              I've always thought of a capacitor using the water tower analogy. Without a water tower, if everyone in town flushes their toilet at the same time, the pressure will drop and starve the system.

                              If you put a water tower in place, you can store large volumes of water by filling it up slowly. When everybody flushes, water pressure is maintained even though the system itself is unchanged except for the tower. When demand is reduced, the tower refills.

                              A capacitor works the same way, supplying a burst of power to keep the voltage up. But if you keep draining it, eventually you outrun the supply capability.
                              Originally posted by ghettocruzer
                              I was gung ho on building a PC [until] just recently. However, between my new phone having internet and GPS and all...and this kit...Im starting to have trouble justfiying it haha.
                              Want to:
                              -Find out about the new iBug iPad install?
                              -Find out about carPC's in just 5 minutes? View the Car PC 101 video

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