Rf Capacitors?
#1
Posted 21 December 2007 - 12:20 AM
(4) 18" Fi BTLs in a 22ft^3 Wall Tuned to 38hz
(3) DC Power 270xp Alternators
(7) Group 31 Optima Batts
(4) RF Prime 6x9s
(4) RF Power 4"
(2 pairs) RF Power 6.5" Components
(1) SD 16KD (Currently)
(1) RF POWER 400.4
#3
Posted 21 December 2007 - 12:31 AM
(4) 18" Fi BTLs in a 22ft^3 Wall Tuned to 38hz
(3) DC Power 270xp Alternators
(7) Group 31 Optima Batts
(4) RF Prime 6x9s
(4) RF Power 4"
(2 pairs) RF Power 6.5" Components
(1) SD 16KD (Currently)
(1) RF POWER 400.4
#4
Posted 21 December 2007 - 12:37 AM
(4) 18" Fi BTLs in a 22ft^3 Wall Tuned to 38hz
(3) DC Power 270xp Alternators
(7) Group 31 Optima Batts
(4) RF Prime 6x9s
(4) RF Power 4"
(2 pairs) RF Power 6.5" Components
(1) SD 16KD (Currently)
(1) RF POWER 400.4
#5
Posted 21 December 2007 - 12:54 AM
smokeumtires, on Dec 20 2007, 11:37 PM, said:
LMAO!
Yes they Make a 40 farad. But there Like $500 IIRC
Steve was The 1st To try It out....
Ask him How it was...There Sick Looking...
I LOVE HATER'S
#6
Posted 21 December 2007 - 01:44 AM
smokeumtires, on Dec 21 2007, 01:31 AM, said:
smokeumtires, on Dec 21 2007, 01:37 AM, said:
Im sorry, but I dont want to burst your bubble or your friends that does not want the added weight.
Well if he is trying to keep his car light he shouldnt add a stereo
But for real, you do not think a 40 fared cap will weight a bit? My old 1 farad rf digitop felt like it weighed at least 2 pounds. I picked up some batcaps also at a shop and even the smallest batcaps are packing a nice weight to them
The fosgate 10farad is ruffly $270 online, msrp is $525... So you can only imaging what the 40farad would be.
Or you buy a kinetik hc600 (their smallest battery) for only $105. It only weighs 14 pounds (which is ruffly the same wieght as a 10 farad cap), and is more powerful than 100 1 farad capacitors!
A battery will also give you a constant flow of voltage/amperage. Where as soon as the beat drops and the cap wastes all its engergy in less then a second ends soaking up more juice trying to recharge and drain as the beat keeps going. So I guess you could say with a 2nd battery (gel cell) you will have a more stable voltage while bumping at higher volumes where as with a cap you will see your voltage constantly altering.
#7
Posted 21 December 2007 - 10:16 PM
(4) 18" Fi BTLs in a 22ft^3 Wall Tuned to 38hz
(3) DC Power 270xp Alternators
(7) Group 31 Optima Batts
(4) RF Prime 6x9s
(4) RF Power 4"
(2 pairs) RF Power 6.5" Components
(1) SD 16KD (Currently)
(1) RF POWER 400.4
#8
Posted 23 December 2007 - 07:31 AM
audiofanaticz, on Dec 21 2007, 03:44 AM, said:
Well if he is trying to keep his car light he shouldnt add a stereo
But for real, you do not think a 40 fared cap will weight a bit? My old 1 farad rf digitop felt like it weighed at least 2 pounds. I picked up some batcaps also at a shop and even the smallest batcaps are packing a nice weight to them
The fosgate 10farad is ruffly $270 online, msrp is $525... So you can only imaging what the 40farad would be.
Or you buy a kinetik hc600 (their smallest battery) for only $105. It only weighs 14 pounds (which is ruffly the same wieght as a 10 farad cap), and is more powerful than 100 1 farad capacitors!
A battery will also give you a constant flow of voltage/amperage. Where as soon as the beat drops and the cap wastes all its engergy in less then a second ends soaking up more juice trying to recharge and drain as the beat keeps going. So I guess you could say with a 2nd battery (gel cell) you will have a more stable voltage while bumping at higher volumes where as with a cap you will see your voltage constantly altering.
thank you thank you thank you....you took everything i would have said and said it for me. thanks for saving me some typing
NoFearX18, on Jan 23 2009, 06:53 PM, said:
BURRITO, on Mar 1 2009, 09:07 PM, said:
trainman0978, on Aug 9 2008, 11:37 AM, said:
#10
#12
Posted 02 January 2008 - 11:33 PM
1. Store charge
2. Oppose changes in voltage
Now, both of those things sound mighty nice to me. To understand how a cap benefits a car audio system, one has to first understand that there are TWO separate voltage plateaus available in an automobile:
1. Running - With the alternator charging, voltages will typically be from 13.8 to 14.4 VDC
2. Not running - With the alternator IDLE, voltages will typically be from 12.0 to 12.6 VDC
I'll take the higher of the two any day. For UNREGULATED amps, this allows them to draw MORE current therby making more power. For REGULATED amps, this allows them to draw LESS current to make their rated power. Either way, it's a WIN for you. So, how do we ensure the higher of the two?
Again, simple. With the vehicle running, consider the DELTA between what the alternator can make and what the nominal voltage the batteries can provide is. For this example, lets assume 14.4 VDC - 12.6 VDC = 1.8 VDC. When we exceed the current output capability of the alternator, it's voltage output is compromised. In some cases, heavy demands of amplifiers can far exceed the current capability of the alternator, leaving us with only the reserve of current within the battery. But, car batteries weren't intended to power amplifiers . . . they were intended to start cars [Battery = Load with vehicle running.] A really fresh car battery can do this for a while, but given that we're exceeding the output capability of the alternator, it's charge isn't getting replenished quickly enough - need about 13.0 VDC minimum to allow charge to flow back into the battery.
A properly sized capacitor will change the rules. With the vehicle running, it stores charge at the higher voltage plateau - 14.4 Volts. As the amplifiers demand current, it will flow from the place of least resistance . . . Ohm's Law tells us that happens to be the place with the highest voltage. That will be in order:
1. The capacitor (closest)
2. The alternator
3. The battery
Ideally, you've selected the correct size capacitor for your system's needs. And . . . that "30F" cap that sells for $59 in a blue velvet box with chrome and a big blue LED readout is just a glorified volt meter These devices have ZERO benefit. There is a reason why quality capacitors cost money, and ours are no exception. These are the facts:
1. A 1 Farad capacitor can store and release 72 Joules (watt*second) of energy at 12 Volts.
2. Said capacitor can charge and discharge hundreds of times faster than an automitive battery of any kind.
3. Capacitors present nearly no load to a properly set up charging system.
4. Automotive batteries require 7 to 10 amps of current EACH to allow charge to flow into them.
5. Capacitors work GREAT for every day street systems.
6. The benefits or capacitors are negated in SPL competitions.
For best results, I recommend locating capacitors within a foot of the amplifier - as in, no more than 12 inches of wire between the capacitor and the amplifier. The further away from the amp they are, the less of a benefit they offer.
I have used them my systems for a very long time . . . since about 1986.
This post has been edited by snafu: 02 January 2008 - 11:35 PM
#14
Posted 02 January 2008 - 11:49 PM
I will be soon running 2 amps for my subs. 3000wrms by 1 @ 1 ohm each. They will be ran daily at around 15.5 volts at around .7 ohms.
My amps will put out 4500wrms by 1 @ 1 16.5 volts.
I will soon have a irragi alt and voltage regulator whenever he gets back to me, just waiting on Dom.
Ive also seen one of my amps draw over 450 amps at ruffly .75-1 ohm.
So are you telling me that running a big capacitor will benifit me more then lets say 4 Powermaster 3100s or 4 kinetik hc2400s?
All I know is anything below 12.5 volts I am at risk of frying mosfets when the amps are ran at 1 ohm.
#15
Posted 03 January 2008 - 10:36 PM
audiofanaticz, on Jan 2 2008, 11:49 PM, said:
I will be soon running 2 amps for my subs. 3000wrms by 1 @ 1 ohm each. They will be ran daily at around 15.5 volts at around .7 ohms.
My amps will put out 4500wrms by 1 @ 1 16.5 volts.
I will soon have a irragi alt and voltage regulator whenever he gets back to me, just waiting on Dom.
Ive also seen one of my amps draw over 450 amps at ruffly .75-1 ohm.
So are you telling me that running a big capacitor will benifit me more then lets say 4 Powermaster 3100s or 4 kinetik hc2400s?
All I know is anything below 12.5 volts I am at risk of frying mosfets when the amps are ran at 1 ohm.
You really didn't give me much information to go off of . . .
- Your amps are obviously unregulated as they can produce more power with higher input voltage . . . maybe T3ks?
- What topology are they? (Class D?, bd?, A/B?) OR, what are their efficiency ratings?
- How much current at 14.4 volts are you paying Dom for?
Some simple math with your 3,000 watt Class D example at 14.4 VDC on sine waves would be:
3,000 / .75 = 4,000 watts Input required x 2 = 8,000 watts input
8,000 / 14.4 = 555 amps of current
Let's say your amps require 17 feet of power wire between them and the batteries and another 5 foot between them and the frame (chassis won't cut it here) for their grounds. To get 555 amps of current to your amps at 14.4 VDC, you'd need:
Big Wire:
- 1/0 AWG wire has .0001 ohms resistance per foot - 22 foot of it will have .0022 ohms of total resistance
- 555 amps through 22 foot of 1/0 . . . 555 x .0022 = 1.22 Volts drop in the cable alone
- 4 runs of 1/0 AWG . . . 555 x .00055 = .30 Volts drop in the wire - mo' better
BEEFY Alts:
- 300 amps at 14.7 volts . . . remember, we lost 3 tenths of a volt in our four runs of 1/0 AWG . . .
- 2 required
Now, if we add batteries, these need 7 to 10 amps of current each to allow charge to flow into them . . . I'm not seeing the benefit with the car running. But, if you wanted to jam this system with the key off then you'd need 'em for sure. Look at the AH rating on the battery you're shopping for. On music, these two amps would require roughly half of the current they require on sines . . . let's say these batteries had a 65 AH rating.
555 / 2 = 277.5 Amps
277.5 Amps / 65 AH = 4.3
So, you'd need 4 to 5 batteries to play this system wide open on music for ONE hour. After one hour, nominal battery voltage would be somewhere around 10.5 to 11 VDC.
And . . . these 4 batteries would require 40 amps of current to allow them to be charged with the vehicle running . . . better get Dom to up those alts to 350 amp models . . .
Ain't nuthin' free . . . Incidentally, this is a case where capacitance just can't cut it. The amount of capacitance a system this size would require would make it cost prohibitive, but if you could swing it, two of our 100 Farad caps of old would certainly help.
Now - where you're getting 16 volts DC you'll have to share . . .
#17
Posted 05 January 2008 - 12:13 PM
Amps - (2) Soundigital SD16K's
Electrical - (2) DC Power 270sp's with dual kit, 3 stepdown modules, and external regulator
More comming soon... stay tuned
Add me @ MYSPACE

#18
Posted 31 January 2008 - 10:48 PM
snafu, on Jan 3 2008, 12:33 AM, said:
1. Store charge
2. Oppose changes in voltage
Now, both of those things sound mighty nice to me. To understand how a cap benefits a car audio system, one has to first understand that there are TWO separate voltage plateaus available in an automobile:
1. Running - With the alternator charging, voltages will typically be from 13.8 to 14.4 VDC
2. Not running - With the alternator IDLE, voltages will typically be from 12.0 to 12.6 VDC
I'll take the higher of the two any day. For UNREGULATED amps, this allows them to draw MORE current therby making more power. For REGULATED amps, this allows them to draw LESS current to make their rated power. Either way, it's a WIN for you. So, how do we ensure the higher of the two?
Again, simple. With the vehicle running, consider the DELTA between what the alternator can make and what the nominal voltage the batteries can provide is. For this example, lets assume 14.4 VDC - 12.6 VDC = 1.8 VDC. When we exceed the current output capability of the alternator, it's voltage output is compromised. In some cases, heavy demands of amplifiers can far exceed the current capability of the alternator, leaving us with only the reserve of current within the battery. But, car batteries weren't intended to power amplifiers . . . they were intended to start cars [Battery = Load with vehicle running.] A really fresh car battery can do this for a while, but given that we're exceeding the output capability of the alternator, it's charge isn't getting replenished quickly enough - need about 13.0 VDC minimum to allow charge to flow back into the battery.
A properly sized capacitor will change the rules. With the vehicle running, it stores charge at the higher voltage plateau - 14.4 Volts. As the amplifiers demand current, it will flow from the place of least resistance . . . Ohm's Law tells us that happens to be the place with the highest voltage. That will be in order:
1. The capacitor (closest)
2. The alternator
3. The battery
Ideally, you've selected the correct size capacitor for your system's needs. And . . . that "30F" cap that sells for $59 in a blue velvet box with chrome and a big blue LED readout is just a glorified volt meter These devices have ZERO benefit. There is a reason why quality capacitors cost money, and ours are no exception. These are the facts:
1. A 1 Farad capacitor can store and release 72 Joules (watt*second) of energy at 12 Volts.
2. Said capacitor can charge and discharge hundreds of times faster than an automitive battery of any kind.
3. Capacitors present nearly no load to a properly set up charging system.
4. Automotive batteries require 7 to 10 amps of current EACH to allow charge to flow into them.
5. Capacitors work GREAT for every day street systems.
6. The benefits or capacitors are negated in SPL competitions.
For best results, I recommend locating capacitors within a foot of the amplifier - as in, no more than 12 inches of wire between the capacitor and the amplifier. The further away from the amp they are, the less of a benefit they offer.
I have used them my systems for a very long time . . . since about 1986.
thank you thank you thank you.
finally someone else that has been using caps for a long time and knows how good they can be.
#19
Posted 28 July 2008 - 05:49 PM
When people don't know how to use a capacitor propperly, they give them such a bad name.
When a person learns how to use a capacitor propperly they can be very benificial to a stereo system.
Ex-Hater
A cap is only good if you have 0 voltage loss and want to clean up the power at the peaks of the ripples..
Boon: Don't get hung up on specs like xmax. It's probably the third-most lied about spec, after power handling and sensitivity.
"Giving up doesn't always mean you are weak; sometimes it means that you are strong enough to let go."
was the fact I won't get to find out whats going to happen tomorrow if I die today.
Insanity: doing the same thing over and over again and expecting different results.
The Destruction of a person builds character.
Hoo-Bangin' on the transformers
Getting my stalk on walk on "Skip skip"
Sack jacking purse snatching hoo-banging till I die

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