CRITIQUE my system
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Anonymous | i have Polk db5250's components on all four doors powered by an infinity 7540a (111w rms x 4) and an re x.x.x. 15"(dual 4 ohm) powered by a mono infinity 1210a (1300w rms x 1 @ 2 ohms). 2 ga. wire runs to tha sub amp w/a 1.5 farad cap(enough?)my head unit is an Alpine 9830. please give me your thoughts. |
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Silver Member Username: LbecknerTulsa, Ok Usa Post Number: 157 Registered: Oct-04 | Sounds nice. Do your lights dim with the 1.5 farad cap? Is 1.5 farad enough? I need a cap, but am not sure how big to get. My amp is 1500 watts. They say to get 1 farad per 1000 watts. I think that more would be better. |
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Anonymous | the system is great, most professional installers would say around 1 farad per 500 watts, you could get a bigger cap but then again, it will be more money so maybe a 3 farad cap, but it will be more money, also most installers will also tell you that a cap is useless, one of whom makes alot posts on this website and, YOU SHOULD TRUST HIM=> G#######F |
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Silver Member Username: LbecknerTulsa, Ok Usa Post Number: 162 Registered: Oct-04 | Caps work great. And its alot easier that adding a battery. And cheaper too. I think I'll go with 5 farads. I found a carbon one for under $100. I hope it is a good one. |
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Bronze Member Username: SubfanaticWalton, Ky Usa Post Number: 41 Registered: Dec-04 | what is this cap you speak of |
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Silver Member Username: InvainMichigan United States Post Number: 280 Registered: Aug-04 | 5 farads for under 100 bucks? I would be careful buying that. Sounds cheap. |
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Bronze Member Username: WojoproPost Number: 89 Registered: Nov-04 | Glasswolf doesnt say that caps are useless... They are not a replacement for an upgraded charging system. Replace that alternator and battery!!!! Do not use a cap as a alternative!!!!! Its not designed for that purpose!!!!!!!!!! |
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Gold Member Username: Jonathan_fGA USA Post Number: 2925 Registered: May-04 | Like Stan said, Capacitors aren't really useless, it's just that they're misused more often than not. A capacitor can't compensate for a lacking charging system, 9/10 times when lights dim with a car, it's due to the alternator, not the battery. If you add a cap to an already lacking charging system, you're adding extra load to your already straining alternator, which may eventually lead to failure. Most factory cars just don't have enough reserve power in the charging system to handle the demands of high powered amplifiers. Once your charging system is up to par, a capacitor can show some benefit. |
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Silver Member Username: LbecknerTulsa, Ok Usa Post Number: 163 Registered: Oct-04 | I have a tax id# and can buy stuff cheap. I forget the brand of the cap. |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 7193 Registered: Dec-03 | since I repost this link repeatedly, and some folks seem to be hyperlink-challenged, I'll just paste the data for everyne  This should explain everything you need to know about capacitors and charging systems. Capacitors. Do I need one? Well let's see. First, I'll define what a capacitor is, how it works, and what it does. This is best done by the following webpage: www.bcae1.com/capacitr.htm Now with that out of the way, I'll give my take on what a capacitor will or will not do for you. A capacitor WILL: -Stiffen voltage rails. If you experience very brief, momentary periods of high current demand that cause the electrical system to falter only at these rare, peak draw times, then a capacitor will supply the additional current needed (when bass hits) to keep your voltage rails stiff, and prevent damage to the car or audio equipment. -Increase response times for musical accuracy by reducing delay caused by transient response times between current demands from the amplifier, and response to this by the electrical system. In other words, your subs will respond more quickly, because they don't have to wait for the alternator to supply additional current at the moment of demand. Amplifiers have to provide a very dynamic and quick response many times. A capacitor can assist in this if the rest of the charging system is up to par. A capacitor will NOT: -replace the need for a larger, high-output alternator and/or a deep-cycle battery or batteries. If your electrical system is inadequate, the ONLY way to fix this, and again I repeat, the ONLY WAY to fix this, is to replace the alternator. This is the SOLE source of electrical current for your car when the motor is running. When the motor is turned off, the battery then becomes your source of electricity. When the battery is run down, and when the capacitor(s) is/are depleted, the alternator has to work even harder in order to supply current to the car, the audio system, and also to recharge the capacitor(s) (which deplete very quickly) as well as recharge the car's battery(ies). So by adding a capacitor to try taking the place of a high-output alternator, you are actually causing more work for your alternator, and causing even more damage to that stock alternator. -make your system magically sound 10 times better. Many people believe that a capacitor adds NO real benefit to an audio system, and this is why you never see before and after demonstrations, or factory capacitor company vehicles at competition events. A capacitor does have it's uses, but it is not a magical fix for a lacking electrical system. To calculate the capacitance needed for your system, you will need to find the peak or max power ratings of your amplifiers, and add those together. This is the only time peak amplifier power ratings are even remotely useful, since a capacitor is only used to cover very brief peak demands, and not cover for the continuous amplifier demands. Take the peak power total and figure 1 farad of capacitance for every 1000 watts of power. |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 7194 Registered: Dec-03 | Alternators and Charging Systems Upon reading and answering many questions about car audio, one question always pops up: "Do I need a high output alternator or just a capacitor?" If you want a killer system, you may think that all you need are big amplifiers and huge speakers. Not so! Adding a bunch of car audio components to your vehicle without the proper charging system may lead you to disappointment, distortion and damaged equipment. Let's say you install a 1,200 watt amplifier in your ride. Your rides charging system must produce enough electrical current to run the amplifier. Now how do you know how much current is needed? Simple: divide the RMS power rating of the amplifier by the amount of voltage your cars electrical system will produce then add in amplifier inefficiency based on amplifier class. Most vehicle electrical systems are 12.5VDC at idle, and between 13.8 and 14.4VDC above about 900rpm but we use 12 volts as the standard for these calculations, so 1,200 watts divided by 12 volts equals 100 Amperes of current. If this is a class D amplifier, it'll be ~80% efficiend, so we'll add 20% of 100A to the total, and we get about 120A of current demand continuously at peak amp output. This means that the electrical system of the vehicle will need to produce an extra 120 Amperes of electrical current to power your amplifier and subwoofer at peak levels. Keep in mind that the factory electrical system is designed to produce enough charging power (alternator and battery) for the vehicle's stock equipment, and was not designed to accomodate high-powered audio systems. The biggest mistake made by consumers and (some) installers is failing to beef up the charging system to handle the extra load of the audio system. First, you need to understand how the electrical system operates. This must be one of the most mis-understood systems of the entire vehicle, so here's a brief summary: Turning the ignition key begins the process of cranking the motor. The battery supplies the power to get things started. Once the engine is running, the electrical burden is shifted over to the alternator. The alternator uses the engine's mechanical power to produce electrical (AC) current. The AC current is passed through a rectifier and changed to DC current which is then sent through a voltage regulator to smooth out and set the voltage rails for the car . The alternator also has the duty of recharging the battery after starting the vehicle by providing a forward bias voltage higher than that which the battery produces on it's own. Everything works perfectly so long as the power requirements of the vehicle do not exceed the capabilities of the alternator. If the peak output is surpassed due to excessive load, then power will be pulled from the battery. If the alternator and battery combined cannot meet the demand, then the vehicle's voltage rails, and subsequently the electrical devices are diminished (dimming lights, spark plug misfires, audio distortion and amplifier clipping, or even the car stalling.) The first place to look to determine if your charging system is up to the task is the alternator itself. If possible, look for the HOT RATING on the alternator. IF you can't see it easily, call a local auto-parts store or car dealership and ask them to look up the stock alternator size, or rating for your vehicle. The hot rating will tell you the amount of power the alternator will produce once the engine reaches it's operating temperature (this is a lower rating than the cold rating). I suggest using your stock alternator unless you experience problems. That's how you know if you need to upgrade, since there is no concrete way to tell if a stock alternator has enough reserve to handle your additional burdens. Now, if you do need a new and larger alternator, after finding the stock rating, then allow your alternator about 10 Amperes credit or buffer area. As a note, when calculating your required current for your audio system, this is an easy way to do it: 1: calculate the total RMS wattage of your system based on how the amplifiers are wired (2 Ohm load, 4 Ohm load etc) 2: take that total RMS rating, and divide by 12 (volts.) 3: add 20% for class D and T or 40% for class AB. (this compensates for efficiency based on amplifier topology) 4: add amplifier totals together for a combined measurement. (in amperes) This is how many Amperes your audio system will require in addition to what your car already needs (stock alternator rating) at full output. For more information on charging systems and alternators, see here: http://www.bcae1.com/chargin2.htm |
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Silver Member Username: WojoproPost Number: 101 Registered: Nov-04 | Hehehe Good job Glass... I should save more links |
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Gold Member Username: GlasswolfNorthWest, Michigan USA Post Number: 7196 Registered: Dec-03 | its all here http://www.wickedcases.com/tutorials/ |
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Silver Member Username: WojoproPost Number: 104 Registered: Nov-04 | Yeah I have your site saved as a link already! |
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Bronze Member Username: FordpwrLos angeles, Ca Usa Post Number: 87 Registered: Dec-04 | If you ever decide to run across the country glass and give classes on car audio , let me know will ya |
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Silver Member Username: WojoproPost Number: 107 Registered: Nov-04 | Yeah! Same here |
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