awkward capacitor experiment.
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=121353
Printed Date: May 10, 2024 at 4:18 AM
Topic: awkward capacitor experiment.
Posted By: rfhvhtoo
Subject: awkward capacitor experiment.
Date Posted: April 14, 2010 at 11:52 PM
I havent been on here in a while so I've had questions and things building up in me...
Now I say awkward because I really want to believe you guys... and the rest of the experts. Now I know i've been told capacitors do nothing just get a HO alt and that will be the best thing you could ever do. So what did i do? I went and got a HO alt, and its doing GREAT!
Then me being the "I want to know because I experienced it" type of person i am, I bought a 30$ capacitor 3.5 farad to conduct my own experiment because "men lie women lie, but Numbers dont." and i've gotta say that is exactly the case in my situation.
I've got 1 BT100 shuriken in the engine bay and a 220 HO alt. and i was going down to about 13v on a steady bass song (because the alternator catches up with the current draw after a couple seconds keeping the voltage steady).
After I put the Capacitor in... I't sits at 13.9-14.1 volts the whole ride... can someone explain? did I just create myself an awesome electrical system??
Amps are Brutus BXI-2408D, and Rockford Fosgate T5002, the amps are that big a variable though since we're mostly focused on voltage. It either drops or doesnt. the only variable is the capacitor added.
https://www.you tube.com/watch?v=SJ0_FXPLLqE
Thats the URL to my With Capacitor video^^^
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Replies:
Posted By: rfhvhtoo
Date Posted: April 15, 2010 at 12:19 AM
I guess the answer that im looking for is Why is it working better than before? and im serious im not trying to Contest people's knowledge im just trying to figure this all out like the rest of us.
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Posted By: anonymous1
Date Posted: April 15, 2010 at 1:17 AM
rfhvhtoo wrote:
After I put the Capacitor in... I't sits at 13.9-14.1 volts the whole ride... can someone explain? did I just create myself an awesome electrical system??
YES Billy Mays himself couldnt tell you how awesome it is with more conviction and enthusiasm. Wait . . . did you just put in one? You're supposed to put them in pairs.
Posted By: rfhvhtoo
Date Posted: April 15, 2010 at 1:28 AM
It's hard to understand exactly what you're saying cause i'm not going well with the sarcasm part, i don't know where it stops. Cause i dont know you. Yes, That was an exciting part of the post. cool? i guess i dont know. But You're saying to put install capacitors in pairs?
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Posted By: anonymous1
Date Posted: April 15, 2010 at 1:51 AM
You did good! And I mean it. You sent $30 on a chance and proved to yourself that the voltage was more stable under load than before, so that's awesome indeed. I wasnt being sarcastic about Billy Mays, but I WAS KIDDING about the pairs part :D Don't doubt yourself. You're doing good work.
Posted By: rfhvhtoo
Date Posted: April 15, 2010 at 2:32 AM
Yeah I had never in life heard that, I was just going to let you explain. You might have been a different country or something lol But thanks alot, I've learned Little after a long hard road of listening and not Doing. Now im DOING, and its Great! :)
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Posted By: oldspark
Date Posted: April 15, 2010 at 3:38 AM
Numbers don't lie, but your voltmeter is.
Make sure you are capturing true-RMS voltages.
(Your result is common. But despite higher apparent voltage, the SPL is probably lower.
You should also look at the voltage waveform on a CRO, or better still, analyse the pre- & post-waveforms with a spectrum analyser. (This is part of the true-RMS issue.)
And then - so you can attack my battery stance - do the same with a low-Z battery (AGM) in place of the cap.
Also note the peak versus RMS voltages in each case.
You will note higher peaks without the cap (or battery in its place, or any battery for that matter (in principle)!) and hence why SPL'ers often omit caps (though that does depend on amplifier PSU etc).
NEVER confuse normal DMM readings with True-RMS etc.
Keep in mind that a cap is supposed to flatten out DC voltages - that means decreasing peaks and increasing dips. Hence the cap should not change the "average" voltage. (Or is that RMS voltage...?  )
And BTW - excellent! Either we find out why I/we are in error, else we cover the details not normally understood.
(EG - why the contradiction - a higher voltage with cap, yet lower SPL??)
Posted By: oldspark
Date Posted: April 15, 2010 at 3:50 AM
An open letter to all the Gurus hereon.
Should this rfhvhtoo show us up, I vote he gets exterminated. Or at least banned.
If others get away with bullsh, why shouldn't we?
And we all know how unstable the boat rockers are - even if it is for the better.
Oh rats - I hit reply instead of PMcc...
(rfhvhtoo - go for it! Any "fact" should be challengable and defendable etc.... excluding where some defenses just aren't understood by the listeners! But let's not mention my previous forum forays....)
Posted By: rfhvhtoo
Date Posted: April 15, 2010 at 12:35 PM
oldspark wrote:
Numbers don't lie, but your voltmeter is.
Make sure you are capturing true-RMS voltages.
(Your result is common. But despite higher apparent voltage, the SPL is probably lower.
You should also look at the voltage waveform on a CRO, or better still, analyse the pre- & post-waveforms with a spectrum analyser. (This is part of the true-RMS issue.)
And then - so you can attack my battery stance - do the same with a low-Z battery (AGM) in place of the cap.
Go For it! The SPL issue isn't really what I'm aiming for but if thats something you guys have been debating this is something good to look into!
oldspark wrote:
Also note the peak versus RMS voltages in each case.
You will note higher peaks without the cap (or battery in its place, or any battery for that matter (in principle)!) and hence why SPL'ers often omit caps (though that does depend on amplifier PSU etc).
I would never try to compare a 30$ Cap to extra batteries.
NEVER confuse normal DMM readings with True-RMS etc.
oldspark wrote:
Keep in mind that a cap is supposed to flatten out DC voltages - that means decreasing peaks and increasing dips. Hence the cap should not change the "average" voltage. (Or is that RMS voltage...? )
Thats what its doing... its keeping my electrical system at 14.0'ish volts not letting peaks and dips into the current path of the amps. I dont get what you're stating here. therefor It SHOULD change the average voltage the amp sees. the Cap Doesnt turn on for certain Bass notes like "Ahh! its a 30hz note! lets go!" No its on for the whole song lol
Exactly Why I am asking this question. But I cant Conduct a Hundred experiments just the Very Cheap ones I can afford. You notice 30$ SoundStorm. If I really believed in Caps I would Have went for Rockford or more Credible Brand at that.
But as you said, how is this cap keeping my Average voltage at the Normal Charging level? When I start my truck it charges up to 14.0-14.2. I've read this forum and looked at others and you 101's and I've never heard of the voltage staying THIS steady.
But why do more experiments and raise more questions when we havent answered this one? if someone has the money to do experiments Go For it! But no matter how many more you do We cant deny the fact that my voltage is now sitting at 14v instead of 13v at full tilt with all of the same variables besides the capacitor. right? or does the voltmeter change its mind when you connect a capacitor? it gets lazy lol
Hey Look im just stating FACTS. The Video states a FACT. Its not He say, she say, they say, its Electrical Components at work. Its the same Voltmeter that recorded 13v before that is now recording 14v. Even if it is "lying" The CHANGE is still a 1volt increase thats TRUE. Can we agree on that?
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Posted By: rfhvhtoo
Date Posted: April 15, 2010 at 3:47 PM
My hypothesis is going to have to be since sound is in a sin wave, the capacitor must be charging when the f(x) is decreasing between the critical points maximum and minimum points. So in between every wave of sound the capacitor recharges and discharges... and that's supported by my video and the results.
I don't mind if anyone challenges my hypothesis, just DON'T SAY the results aren't there. Because it is in the link up there. I told you if you want me to do a vid without the cap I will.
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Posted By: rfhvhtoo
Date Posted: April 15, 2010 at 4:47 PM
what am i talking about? challenge it all!!! I just want to try an figure out the reasoning.
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Posted By: ianarian
Date Posted: April 15, 2010 at 7:21 PM
The voltage on that stinger gauge is not accurate. At any given time it may or may not be giving you the correct reading. I have a video of proof of that available if you want to see. If your analysis is based on that Stinger gauge then the research is not legitimate. How did you wire the cap in? Do you have distribution blocks that you added to? Or is the cap the distributor now and distribution blocks were removed? I am most concerned with the voltage level your getting. The upgraded alternator should be getting a higher charging voltage. It cant be a 220a alt without a strong voltage to drive it. From the viewpoint of a electrician, will adding a 3.5f cap to a electrical system with a 220a alt and a bt100 result in a additional volt of power,-\=$&^(^&^$&^ NO! There is something incorrect about the entire thing. To prove ME wrong, A vid of the system and a real DMM meter showing before and after results of a cap being added and removed would have to be presented. Beyond that, if you think you are better off with it in the system, then rock on with it, FUGGIT! Sounds like your happy with it, and that's totally enough reason to have it in the system, understands me?
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This is what I do for FUN!
Posted By: stevdart
Date Posted: April 15, 2010 at 9:20 PM
I have always heard, from this forum, to upgrade the electrical system FIRST, which you have done. THEN, if you want to, add the capacitor for smoothing voltage fluctuations. Which you, again, have done. Good work, and thank you for sharing your experiment. The capacitor issue has always been that users were trying to fix voltage / power issues by merely adding the cap. But you upgraded your electrical system. That's the difference. Here's an oldie moldie thread that illustrates the consensus, I think. Look at haem's response: "unless you have a current source (the alternator) to run everything perfectly capably without one, THEN you could add one, but you will probably see very little improvement."
___________________________________________ ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: oldspark
Date Posted: April 15, 2010 at 10:50 PM
rfhvhtoo wrote:
I would never try to compare a 30$ Cap to extra batteries
I am usually comparing new batteries from $20-$35 (some the size of a couple of cigarette packets) to multi-Farad caps worth hundreds of dollars.
If caps were as cheap as batteries, the cost-basis for that argument would change.
rfhvhtoo wrote:
The Video states a FACT
Or it shows something open to interpretation or understanding.
In the case of waveforms, it may lack info. EG - to find whether a particular (sinewave) voltage frequency contributes to power, you need the current's sinewave for the same frequency. Hence the need for spectrum analysers etc.
But a CRO (waveform) shows much that a voltmeter doesn't. That's the point here - we/you will delve deeper and uncover more, and hence learn more....
In terms of Forum writings, I haven't gotten past cap & battery ESRs versus system ERSs (amp PSU impedance etc) even on a static DC level (let alone longer term dynamic responses/decays etc).
And with that - another point - ensure you record that what & how etc. It is important to know what components (models etc), wire gauges, connection blocks, meter impedances, time scales etc. (Welcome to the world of scientific testing - where things need to be reproducable etc.)
It's no good trying to dispel a cap myth if a cap with high ESR (say 0.1 Ohm) if ESR is important. (And I say if!) Though not knowing whether the cap was hi or low ESR is worse. It's like not distinguishing between a fully charged 0.002 Ohm ESR battery and a 1.2AH battery.
But many misunderstandings are likely to fall out.
For example, that a high output alternator should have a higher voltage. (No - it's still up to the normal 14.4V DC.)
PS (sorry - longus phonus interruptus).
The amps output sinewave reflecting thru the amp's PSU is dependent on the amps quality and internal "tank".
And an alternator is NOT a current source - it is a voltage source. (I am talking electrical nomenclature - a current source varies the voltage to delver the current. A vehicle's battery system is a "constant voltage system" - not current.
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