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Diesel questions, newbie

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  • Diesel questions, newbie

    I have a 1979 300CD Mercedes which already as a 500 watt amp in it. Diesels require a lot of power for start up, especially in the winter since they use glow plugs to warm up the engine block before they start. Suppose I am driving on a rainy night, with mp3 cranking and headlights. Would I be draining the car battery so that I couldn't start up in the morning? Also has anyone tried connecting their system to other car electronic stuff, such as radar detectors, power windows, alarm systems, or dashboard. I always thought it would be neat to hear a radar detector through the car audio system rather than drowned out by the audio volume.

  • #2
    Hi there mate...

    It sound like i had same sort of problem.
    I got 2 amps (200watts and 300watts with 2 15" subs), EQ, MP3 player, and usualy at night with head lights on the voltage would go down even up to 10v and it would of be hard to start the car in the morning (usually 20 mints of battery charging gets the car going again).

    Well there are few options usually to consider...
    You can install the second car battery or 1 farad cap. It will keep your voltage up and not so much load on the altinator and the your car battery.

    And try to mount it as close as you can to your Amp.

    Also with that 500watts amp you got it put out heaps more dbs than ur small radar detector. What i did with my radar detecor was (its illigal here to have one of those detectors in the cars ) as soon as it would detect any police action it would mute
    the stereo system (its also illigal here in Australia to have the system up above 90dbs)and also turn the radar detector off so police won't catch me with that thing, while it will active police worning signal for few seconds.

    Thats how i got over those problems!
    OK then good luck mate.

    Fosgate
    Fosgate

    System Comp V3 - In progress.
    Low power MB with C7 CPU, DC-DC PSU, car ECU link, USB TV, GPS, 7" TFT, Wireless, Voice.

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    • #3
      Hey Fosgate.. give me an email at [email protected] about those radar detectors.. I didn't think they worked in Austraila cause of the new technology camera's like speed camera's and those damn radar guns taht get you from 1klm away..

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      • #4
        Fosgate, Caps are designed (in the car) to reinforce momentary sags in electrical system voltage, primarily to prevent amplifier clipping under transient loads. High current stereo systems can be very hard on batterys I'd have the battery/electrical system tested you could have a bad battery and or alternator. Also I don't know what kind of amps your using but the ones we run over here (most of them) are designed to shut down if the voltage drops below 10.5 or 11 volts to prevent amplifer damage due to excess current draw, are they the same there?

        Hemant,

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        • #5
          Fosgate, Caps are designed (in the car) to reinforce momentary sags in electrical system voltage, primarily to prevent amplifier clipping under transient loads. High current stereo systems can be very hard on batterys I'd have the battery/electrical system tested you could have a bad battery and or alternator. Also I don't know what kind of amps your using but the ones we run over here (most of them) are designed to shut down if the voltage drops below 10.5 or 11 volts to prevent amplifer damage due to excess current draw, are they the same there?

          Hemant,

          Comment


          • #6
            Hello there

            Well i been installing car stereo system few years now and i really havent came across amps which do cut off at low voltages.They usualy cut off at high temps or high load on them. Most high class amps have good regualtion circuts which can handle voltage drop even up to 9 volts. Im not talking about amps here but also American brands too. Lets take a look at Rockford Fosgate 500x2, 800x2 those amps handle high temperatures and up to .25 ohms of load and with enough current they can still be operating with voltage drops to 10volts.

            When i say voltage drop i dont mean a constant voltage of 10volts. The volatge only goes down to 10v when you get amp outputing close to max power. constant voltage drop can get up to 11.5v (if altinatore is charging)in some cases where too much load is applied on the electric system.

            The Caps or an extra battery help to keep the voltage from shifting up and down and keeps this shiftment in smaller range. Also in some cases it also can keep the continues voltage up so it wont reach critical level when high load is applied.

            I persoanly recomend a Cap or an extra battery if you got more than 1 high power amp (RMS 800watts and up) and like listening the music with at least 140dbs output
            Fosgate

            System Comp V3 - In progress.
            Low power MB with C7 CPU, DC-DC PSU, car ECU link, USB TV, GPS, 7" TFT, Wireless, Voice.

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            • #7
              Hi, I've done some reading about voltage drops in car audio.

              Adding an extra battery actually makes it worse. The voltage of your altenator is around 14.4V, the voltage of a battery is around 12.8V. So adding an extra battery only adds to the load on the altenator. If your voltage is dropping to 10V then that means your battery is acting as a source and that's not supposed to happen while the car is running. Adding an extra battery would cause the voltage to drop quicker but may remain a bit higher than 10V. The battery has two purposes, starting the car and running your stereo while the car is off(or whatever it is you run when the car is off). In car stereos the main reason an extra battery is added is to increase engine off playing time.

              Adding a cap is one fix but some will argue you must get a new altenator.

              Treatment like this to your altenator will unfortunately lead to a dead altenator. Or so they say (its never happend to me, yet).

              Wex

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              • #8
                Hey guys,

                A cap won't help you at all when it comes to making the battery last longer. That cap still hasta get charged somehow =). A second battery would ensure that your car would start if you isolated it properly. But this still doesn't solve the problem of the long rainy night of driving with headlights, wipers, heater, and stereo on. =) Your MP3 player won't draw enuf current to have a huge impact on your overall system, so don't sweat that. Really, your only option to truly eliminate/minimize the problem is to get an alternator that puts out more current. You can buy a new one from Phoenix Gold or something, but it will cost you an arm and a leg. You might consider taking that alternator down to your local alternator shop and have them 'rewind' the thing for higher output. Thats what I did! Hope this helps. Good Luck

                Low

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                • #9
                  hello there

                  wexdafid when the batteries are charged they dont put much of load on the altinator they work like a big Caps. And also help to reduce the discharge time and rate. However if both batteries are fully dischaged thats when you will get high load on you altinator and as mentioned above you might end up damaging it. So installing second battery will insure longer discharde time while car if off also more stable voltage and slow descharge rate if the cars electrical system is on high load while altinator is running

                  So i recon this is a one way to go.

                  Fosgate
                  Fosgate

                  System Comp V3 - In progress.
                  Low power MB with C7 CPU, DC-DC PSU, car ECU link, USB TV, GPS, 7" TFT, Wireless, Voice.

                  Comment


                  • #10
                    Fosgate, the batteries are not acting as a cap in this situation, they are acting as a source when the voltage drops to there level. Imagine two different sources wired in parallel, each with different voltages. The source with the greater voltage will keep trying to charge the source with the lower voltage. Even if your batteries are fully charged they are still only 12.8V so they are still a load to the altenator. This is why adding another battery does not help with the voltage drop it only makes it worse.

                    Caps are different because they will charge to the applied voltage across its terminals. Slight voltage variations are smoothed out from the cap charging and dischagring to the applied voltage.

                    A battery won't help with a slight voltage drop because its voltage is still 12.8V while the altenator should be around 14.4V. Meaning the battery won't be acting like a source when the altenator is operating where it should be. So if the altenator takes a .4V drop then the battery isn't going to help any. A cap will help because he is charged to the altenator's Voltage of 14.4.

                    If your voltage is dropping down to 10V then you are ruining your altenator. So if you add an extra battery it may only drop to 11V, but its still ruining your altenator.

                    What I'm trying to say is your battery(s) are acting as a source only after you've pushed your altenator to it's max output and is now producing lower voltages.

                    This idea of adding extra batteries to fix voltage drops is what's called a "Car Audio Myth". I used to think the same thing you do about extra batteries.

                    LowLife is correct that you must upgrade the altenator to properly fix this problem.

                    One more thing to add. Some cars have very slow regulators(I notice this on some ford cars, say I turn on lights, it takes a moment for the altenator to get back up to 14.4). So when some electrical device kicks on or bass hits their will be a voltage drop, this is not always do to altenator problems. A fix would be to add a 1Fard cap or more.

                    Wex

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