Is a Capacitor worth it?

[AlterEgo99 5,000+ posts]

I think the ESR argument should be handled like this... yes... we all agree that paralleling resistors/resistances drops the equivalent resistance. Having 2 bulbs in parallel shows a smaller resistance than 1 bulb, but it still requires double the power. What do you define as "load"? If you say straight resistance, yes, it is smaller. But you still have double the power (and current) requirement. Whatever source your using still has to supply double the power (or current), therefore it is loaded harder.
I'm just trying to bring a little civility to this thread //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I may have missed it (this thread has gotten quite lengthy) but what cap(s) are you using and where do you have it located?

 

[AlterEgo99 5,000+ posts]

...i have a 150A alt with 2 batts and 20 caps with 2 shunts inline with the alt and amp so i can monitor the current used by my system and workout rough wattagesand my alt doesnt normaly go above 100A so that another 50A posible avalible from my alt

You have 20 caps!? I'm used to these big *** 1 to nn farad caps that are sold over here in the U.S...maybe it's different in the U.K.? Can you explain? //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[smoka 10+ year member]

HAHA ****, good word. I haven't heard that since 4th grade. ESR does not equal resistance. It's EQUIVALENT series resistance. I wonder why the put the term "equivalent" in there if it's just series resistance... hmmm.. DUH!!!!
HAHA so you ARE actually saying that the more amps or batts you put in a system the less the resistance? That's hilarious because if that were the case, the more shit you hooked up the better your electrical system would perform. You're a dolt.

ESR is the total resistance of a series circuit where all individual resistances are equal. How is that not resistance???

lol, well you obviously know everything there is to know, and everyone here is wrong, so I guess theres no point in me continuing to disprove your posts....

You keep talking about school, do you care to share your education and profession with us that makes you so much better than everyone???

 

[Stalin-ohaulic]

ESR is the total resistance of a series circuit where all individual resistances are equal. How is that not resistance???
lol, well you obviously know everything there is to know, and everyone here is wrong, so I guess theres no point in me continuing to disprove your posts....

You keep talking about school, do you care to share your education and profession with us that makes you so much better than everyone???

where all individual resistances are equal? That's not true. Look up the definition again. I was hoping some idiot would call me on the esr thing. Resistance can be measured with a DMM right? You measure it in ohms. Go measure a cap's resistance with a dmm. Now that you know you're wrong.... esr changes with frequency. How does that affect the cap when it's in the circuit?

These are all things you obviously don't know. You walked right into the trap. The other guy figured out it he was wrong and left it alone.

Also, why would I want to share my career with you? I saw how you guys tore into the EE. I'm not going down that road. What is it that you do that makes you so uninformed? Do you work for the news media?

 

[PaulD 10+ year member]

good grief, ESR is just the effective resistance in series with the "perfect device". In theory, a cap has only capacitance - in reality it has a small amount of resistance, which we denote as ESR in this case.

The problem is that even a small amount of resistance will make the cap useless in this appication. With just a 100 amp draw and a 20 milliohm (.02 ohm) ESR, the voltage drop will be 2 volts .... V=IxR or voltage drop = 100A x .02. The "power" stored in the cap has to do with the voltage level, since most amps will cut off around 10 volts sob you you really only have access to about 30% of it's stored charge anyway (14-10 / 10)

 

[Stalin-ohaulic]

good grief, ESR is just the effective resistance in series with the "perfect device". In theory, a cap has only capacitance - in reality it has a small amount of resistance, which we denote as ESR in this case.
The problem is that even a small amount of resistance will make the cap useless in this appication. With just a 100 amp draw and a 20 milliohm (.02 ohm) ESR, the voltage drop will be 2 volts .... V=IxR or voltage drop = 100A x .02. The "power" stored in the cap has to do with the voltage level, since most amps will cut off around 10 volts sob you you really only have access to about 30% of it's stored charge anyway (14-10 / 10)

I find no fault with the math or the fact that the benefits are limited. I DO find fault when you said they are useless. They are useless for people who think they are the magic bandaid. They are not useless for cleaning up the power going through a properly designed electrical system. Saying anything else is ridiculous. I think you forgot a 0. Even crappy caps have .002 ohms esr. http://www.sonicelectronix.com/item_18671_Raptor+C1F.html

 

[smoka 10+ year member]

esr changes with frequency.

Please explain how a lead-acid battery is subject to changes in frequency.

 

[Stalin-ohaulic]

Please explain how a lead-acid battery is subject to changes in frequency.

"ESR is the sum of in-phase AC resistance. It includes resistance of the dielectric, plate material, electrolytic solution, and terminal leads at a particular frequency. ESR acts like a resistor in series with a capacitor (thus the name Equivalent Series Resistance). This resistance often is the cause of failures in capacitor circuits. These circuits look just fine on paper, but the hidden resistance causes failure due to heat buildup."

http://wiki.xtronics.com/index.php/Capacitors_and_ESR

I'm just defining Cap ESR.

You can attempt to twist things I said into something I didn't say, but it's all right there in black and white. You're wrong and you know it. Now you're trying to put words into my mouth in hopes that you can "catch" me. The problem is, when someone is telling the truth you can't catch them in a lie.

 

[smoka 10+ year member]

Where are your amps grounded? Also, the only way a batt can help with dimming is if you replace the batt up front from one with a higher esr to one with a lower esr. Then it helps because it is less strain on the alt.

Who is putting words in your mouth? You referred to a batts internal resistance as esr ("sum of in-phase AC resistance") but now you can't explain it? I guess thats what happens when you copy stuff off the internet without knowing the theory behind it.

I'll admit I was wrong about the definition of esr, I've never heard of esr in regards to a battery and assumed it was referring to the parrallel/series internal network in the bat. I did not google it before posting as my knowledge is not copy/pasted from the internet (unless I need to find support references).

By background is in batteries, I don't think any of my posts have referenced caps. The cap debate is old, its been discussed 100's of times in this forum and is always the same.

 

[Stalin-ohaulic]

Who is putting words in your mouth? You referred to a batts internal resistance as esr ("sum of in-phase AC resistance") but now you can't explain it? I guess thats what happens when you copy stuff off the internet without knowing the theory behind it.
I'll admit I was wrong about the definition of esr, I've never heard of esr in regards to a battery and assumed it was referring to the parrallel/series internal network in the bat. I did not google it before posting as my knowledge is not copy/pasted from the internet (unless I need to find support references).

By background is in batteries, I don't think any of my posts have referenced caps. The cap debate is old, its been discussed 100's of times in this forum and is always the same.

Well the problem there is with semantics. You really weren't wrong on the esr of the batt. It's not really esr as defined by a capacitor. ESR is sort of used inappropriately on batteries because if you measure the batts' resistance it will be 0 but it obviously has some. This is why people refer to a batt or an amplifier or any device connected that has resistance that can't be measured through conventional methods as having esr.

I think sometimes when the cap argument is going down, people only think about a super long, heavy bass note. In that case, sure it makes a cap worthless if the alt cannot keep up. If you're listening to transient music and have a strong electrical system, the cap will clean the power up. There is really no debating this. It's what I've said the whole time and it's true. Also, I don't have some internet degree in electronics. I know these things and then when someone challenges me I just go find it. I think by now you know I'm not in here lying and blowing smoke.

 

[natisfynest 10+ year member]

Well the problem there is with semantics. You really weren't wrong on the esr of the batt. It's not really esr as defined by a capacitor. ESR is sort of used inappropriately on batteries because if you measure the batts' resistance it will be 0 but it obviously has some. This is why people refer to a batt or an amplifier or any device connected that has resistance that can't be measured through conventional methods as having esr. I think sometimes when the cap argument is going down, people only think about a super long, heavy bass note. In that case, sure it makes a cap worthless if the alt cannot keep up. If you're listening to transient music and have a strong electrical system, the cap will clean the power up. There is really no debating this. It's what I've said the whole time and it's true. Also, I don't have some internet degree in electronics. I know these things and then when someone challenges me I just go find it. I think by now you know I'm not in here lying and blowing smoke.

going along with the argument since amps have capacitors in them already doesnt that make having a external one pointless

 

[SomeGuyDude 10+ year member]

going along with the argument since amps have capacitors in them already doesnt that make having a external one pointless

Well to keep playing the analogy game, your computer has a cooling system in it but that doesn't mean if you start pushing the thing to its limits you won't need an external one.

 

[natisfynest 10+ year member]

Well to keep playing the analogy game, your computer has a cooling system in it but that doesn't mean if you start pushing the thing to its limits you won't need an external one.

understandable if you own a POS but if you own a nice quality piece whats the point

 

[Lambo911 10+ year member]

I would not recommend getting a cap. Just beef your alt and batts

 

[Stalin-ohaulic]

understandable if you own a POS but if you own a nice quality piece whats the point

Well by the same logic then why do you need a batt either? I mean if the caps in the amp are perfectly adequate to filter the power in all cases I suppose a batt is unnecessary too right?