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Old 2nd August 2007, 16:39   #1
j_j
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Question Is it better to add a Capacitor or a Secondary battery?

Just a small thought, to which our Gurus will give a conclusion

Insted of adding a capacitor costing 5K n above can we add a second battery ( A bike one, say Kinetic batt). That is by using a dual-battery isolator: a device that allows the second battery to be charged by the alternator, but prevents the amplifiers that are connected to the second battery from drawing any power from the main battery. Or by diectly connecting parellel to the main batt.

Coz bike batt is not that xpensive and small in size, does not need very thick wires like normal ones, can hide them in the booth easily.

Few Pionts:

And batteries are designed to store electrical energy for longer periods of time n discharges slowly.

Where as a capacitor charges and discharges very rapidly. The reason behind this is due to the internal resistance of both devices. A battery has a high resistance that allows for long-term energy storage and a slow discharge. The capacitor has virtually no internal resistance, which allows for rapid charges and discharges.

So can we try this out, or has some one tried this already? I know they have tried with big car batt, but was wondering about trying a 12 V bike batt.

The connection should be parallel with the amplifier right?

As of now in my car dimming is not so much, but i am planning to add a Mono Amp n two 12" kickers.

Now its upto the Gurus here to come out with the concluding idea.
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Old 2nd August 2007, 17:39   #2
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change the BIG 3 and opt for good quality wires, you would not need a cap or battery.
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Old 2nd August 2007, 17:50   #3
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Quote:
Originally Posted by j_j View Post
As of now in my car dimming is not so much, but i am planning to add a Mono Amp n two 12" kickers.
The idea is good but you need to have the same battery both in the front and rear or the battery internal resistance variation will drain them...

about the sub part there are much better brands than kicker....
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Old 2nd August 2007, 18:26   #4
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panky12345,

What is BIG 3?

low_bass_makker,

Quote:
The idea is good but you need to have the same battery both in the front and rear or the battery internal resistance variation will drain them...
Do think it might be worth trying or its just piontless, n to stabilize the internal resistance is there an alternate?

Quote:
there are much better brands than kicker....
Which would be better, planing to go for a Alpine MRP-M650 mono Amp max.
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Old 3rd August 2007, 11:02   #5
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have a look at BIG 3:

http://www.team-bhp.com/forum/ask-gu...tml#post224669
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Old 3rd August 2007, 14:53   #6
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Quote:
Originally Posted by j_j View Post

And batteries are designed to store electrical energy for longer periods of time n discharges slowly.

Where as a capacitor charges and discharges very rapidly. The reason behind this is due to the internal resistance of both devices. A battery has a high resistance that allows for long-term energy storage and a slow discharge. The capacitor has virtually no internal resistance, which allows for rapid charges and discharges.
Exactly why we use capacitors and not batteries. The transient time of a capacitor is quick. It is used to stiffen the current in case of a quick demand (like a bass note). You need something with a quick charge and lightning quick doscharge. It is the discharge that stiffens the current when the amplifier needs it the most.
A capacitor is not the same as a motorcycle battery. You cannot interchange them.

There is another long post on capacitors I wrote somewhere. I cannot find it now. LBM, can you help?
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Old 3rd August 2007, 16:00   #7
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Quote:
Originally Posted by Sam Kapasi View Post
There is another long post on capacitors I wrote somewhere. I cannot find it now. LBM, can you help?
I think it is this one...hope i am correct..

http://www.team-bhp.com/forum/ask-gu...mono-amps.html

Quote:
Originally Posted by Sam Kapasi View Post
Oh well, what a Sunday. Firstly to go to sleep on a saturday night with no sex, now this question. lol

Amit,

All amplifiers (home and car) have caps in them. They typically vary between 4700mfd to 6300 mfd (there is no hard and fast rule here) mostly there will be an entire bank of these, resulting in close to 20000mfd. (2X10raised to 3 mfd). Actually the industry standard for measuring capacitance is is MICROfarad.
These capacitors are placed in the secondary section of the power supply. Let me explain - though it seems that a car amplifier runs on 12V, it actually runs on voltages much higher than those. A car amplifier typically uses a chopper smps, to upscale 12V to voltages many times higher.
A capacitor has 2 basic properties. How many MicroFarad and how many maximum volts it can handle.

Caps generally used inside these amplifiers have a higher voltage limit, as car amplifiers run from 44VDC to 150VDC internally. again there is no hard and fast rule, this will depend on the manufacturers circuit design. The role of the internal cap is to smoothen out the spiky waveform of the voltage generated by the internal chopper transformer an d power supply.

The external capacitor however, is attached in the PRIMARY circuit. BEFORE the 12V is upscaled, chopped or converted. It's role is to provide a steady 12V and a lower transient response time with minimum dipping or peaking.
Though it's capacitance is high 1FARAD is 1X10raised to 6mfd, it's maximum voltage rarely exceeds 15V, because it doesnt need to.

However, a 1F, 100V capacitor (also known as a condensor) would probably be bigger than a NOS cylinder.

Considering your argument about small technology, let me consider your very example. The best cameras are still big. That's why rudra did not buy a Nokia N90 instead of a Canon EOS1D. Consider that the canon EOS1 size is more or less the same for about 20 years now.
Remember, they dont make movies with a Sony ericsson, they still have huge dollies with rocket launchers on them.
Small technology often is pseudo technology.

Now that we have understood the difference between the inner caps and external caps, and why a good technology can never be too small (too soon), let us consider your question - why do companies not incorporate a (say) 0.5F capacitor inside the amplifier.
Thats because not everyone who buys a mono amplifier needs to or thinks he needs to put a capacitor. Though technically it should help a lot, often the results are not very audible to all. A capacitor is not an absolute necessity. Often I would put it last on a list, or not at all. It is more important to get good equipment, followed by good cables, damping and then if you feel the need, you add a cap. Also you ONLY add a cap when you play loud and hard, basically when your current draw is huge and fast. otherwise, the car battery is probably the best capacitor you've got.
When you have something that is expensive and not required by all, why would you change the market value of an amplifier, by adding a capacitor to it?
Capacitors are a matter of choice and that's why companies will leave it that way.

Hope this shed some hair,

Dhoom machale dhoom, but respo nsibly.
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Old 3rd August 2007, 17:22   #8
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Thank You Sam Kapasi n low_bass_makker,

Quote:
A capacitor is not the same as a motorcycle battery. You cannot interchange them.
After seeing all the advice from you gurus i 100%.
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