snafu

Capacitors - What's the REAL story?

257 posts in this topic

waiting for the link to buy the book to get the answer

:unknw:

:ninja:

Edited by sensai_v3.6
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Mr. D - I was waiting for your input, what took ya' so long?

Now, let's say that we were playing music at clipping with our 5kw system . . . think 20ms or so on peaks. How's that math work?

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i would say for a car system under 1500 rms you can use a battery and a capacitor that was the old school way now days as we progressed you have to upgrade your alternator put extra batteries in and more

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i would say for a car system under 1500 rms you can use a battery and a capacitor that was the old school way now days as we progressed you have to upgrade your alternator put extra batteries in and more

No offense, but I think you're missing the point. The power that a cap can put out is limited to the amount of potential difference in the power that the cap contains and the input voltage that the amp is getting. A cap in itself will not contain enough energy to provide ample power to offset the potential difference for enough length of time to make a difference.

A battery is exponentially more powerful than a cap, and therefore can offset potential differences in the input voltage. Nothing is going to completely overcome an inadequate charging system, although a battery bank can give you reserve capacity to lessen the potential difference until the electrical demand drops low enough that the alternator can meet the demand and ultimately recharge the batteries.

Conclusion:

1.alternator with enough headroom is a must

2. followed by supporting mods (big 3, proper grounds, etc)

3. battery bank large enough to support the length of time that playing at volumes that require more power than charging system can produce

Unless, you're able to make room and pay for 2500(1F) capacitors, to be used in 30 second increments (sorry, no playing full songs)

Thanks Tony D

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Mr. D - I was waiting for your input, what took ya' so long?

Now, let's say that we were playing music at clipping with our 5kw system . . . think 20ms or so on peaks. How's that math work?

Well subwoofer amplifiers are what we are talking about here, and 20ms isn't bass. Just one cycle of 50Hz is 20ms. I measured a kick drum back in the Rockford Days to be well over 100ms. I'd go as far to say, as far as modern synthetic compressed bass, anything less than a second of storage is fairly meaningless.

Edited by TonyD'Amore
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Corrected version:

J=(CV^2)/2 (J= joules, C=capacitance, V=voltage)

for a 1 farad capacitor on a system charging at 14.2 (voltage = random number somewhere around normal car voltage I pulled out my ass for the sake of this post)

J = 1 x (14.2x14.2) / 2

---->snip<-----

So who's buying me a 2500 farad capacitor bank?

... OUCH. thanks for the correction and further proving my point of how worthless caps are for guys like us. :cheers:

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Since the smart guys are in here I'll ask this question.

How do batteries interface with caps? Considering the low esr wouldn't a battery see a cap not at potential voltage as a short circuit?

throw some more numbers at me in a realistic situation like above

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Mr. D - I was waiting for your input, what took ya' so long?

Now, let's say that we were playing music at clipping with our 5kw system . . . think 20ms or so on peaks. How's that math work?

Well subwoofer amplifiers are what we are talking about here, and 20ms isn't bass. Just one cycle of 50Hz is 20ms. I measured a kick drum back in the Rockford Days to be well over 100ms. I'd go as far to say, as far as modern synthetic compressed bass, anything less than a second of storage is fairly meaningless.

Did you leave Rockford cause they wouldn't stop selling useless caps? I kid I kid

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cant we just get the answer!! I want to learn!! i read through 8 pages. snafu!! i want the answer!!!! :Doh::dammit:

me "give me the answer now!!!" >>>> :fryingpan:<< snafu "not yet, you must keep guessing and thinking and burning your brains out"

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