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cap kills battery?

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=123096
Printed Date: April 20, 2024 at 7:37 AM


Topic: cap kills battery?

Posted By: Blowntweeters
Subject: cap kills battery?
Date Posted: August 12, 2010 at 5:45 PM

 so this cheap cap keeps killing the car battery.  will a battery isolater fix my probelm? or can i fix it just with wiring changes? im using the cap as my power distribtion. any help would be great. thanx

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1974 ford pinto 4 15" punch Z power punch bd 1001 pioneer DEH-6700



Replies:

Posted By: i am an idiot
Date Posted: August 12, 2010 at 8:47 PM
posted_image




Posted By: oldspark
Date Posted: August 12, 2010 at 9:10 PM
I'll second that.

(As if expensive caps weren't bad enough! Now have cheap caps that kill batteries.... wth???!!! Maybe it's an inductor (from +12V to gnd)?)




Posted By: 66sportfury
Date Posted: August 12, 2010 at 10:37 PM
why would a cap kill a battery? shorted? but then it should expand, like a over charged battery right?

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ac delco am radio and sparkomatic 40 watt sound exploder




Posted By: oldspark
Date Posted: August 12, 2010 at 11:39 PM
Collapsed, leaking (electrically), partial short.

On other words it has failed and hence no point keeping it - it certainly isn't "holding up the voltage" like it's suppose to.
(I'm assuming the OP knows it is a failed cap that is killing the battery as opposed to over or under charging, faulty alternator, excessive discharge etc. He's was on the right track for the solution - namely an isolator, but in this case, one that does NOT reconnect the cap.)


Caps do fail - especially electrolytic types (which I presume car audio batteries to be).

Not that anyone here can explain why you would want to use a cap in a car or audio system (as compared to other solutions).





Posted By: 66sportfury
Date Posted: August 13, 2010 at 11:03 AM
they are inexspensive, and easy to install. even though they not the smartest route but its even common for shops to recomend a cap. instead of up grading the alt,

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ac delco am radio and sparkomatic 40 watt sound exploder




Posted By: oldspark
Date Posted: August 13, 2010 at 11:19 AM
Sorry - I didn't realise caps were cheaper than a $10-$20 AGM battery.
It makes you winder why they are so keen on them if they are so cheap - maybe they have a bigger profit margin on caps?
I saw a Stinger 1F or 1.5F advertised here for $450. LOL - you can get a yellow top for that!

But neither have anything to do with upgrading the alternator - well, not much anyway.
An alternator is generally upgraded if is isn't outputing sufficient power to charge the battery. Caps and (small) AGMs are not there to make up for those power shortfalls.




Posted By: cachanilla
Date Posted: August 13, 2010 at 2:45 PM

i am an idiot wrote:

posted_image

I never get tired of this! LOL 

I am an idiot; you are the man!





Posted By: 66sportfury
Date Posted: August 13, 2010 at 3:28 PM

oldspark wrote:

Sorry - I didn't realise caps were cheaper than a $10-$20 AGM battery.
It makes you winder why they are so keen on them if they are so cheap - maybe they have a bigger profit margin on caps?
I saw a Stinger 1F or 1.5F advertised here for $450. LOL - you can get a yellow top for that!

But neither have anything to do with upgrading the alternator - well, not much anyway.
An alternator is generally upgraded if is isn't outputing sufficient power to charge the battery. Caps and (small) AGMs are not there to make up for those power shortfalls.

A battery is the same principle as a cap, they are just both Band-Aids for a charging system that cannot keep up the audio system,

And yes there is a big markup on caps.

At least there was when I was working car audio



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ac delco am radio and sparkomatic 40 watt sound exploder




Posted By: i am an idiot
Date Posted: August 13, 2010 at 7:25 PM

I work in the oldest still in operation Car Audio shop in my town.  At one time we too jumped on the capacitor band wagon.  This was because at every car stereo competition, the judges were reccomending capacitors to every participant they judged.  They made these recconendations just as they have reccomended other things.  What the participant did not realize was the judge was actually a rep for a marketing firm.  And guess what, they just happened to sell Brand _____ capacitors.  They did not suggest that you buy their brand of capacitor, but they suggested them.  So the next day every kid at the contest would come in looking for a capacitor.  Some of the kids visited a shop that was supplied by the rep that was judging the contest.  Some visited other shops.  But at the end of the day, that rep increased his bottom line.  We sold them only briefly, once it was figured out that they DID ABSOLUTELY NOTHING to improve sound or increase sound pressure levels more than 1/1000th of a dB, we as a reputable stereo shop chose not to even sell them. 

We have had cars in the work area for a decent size system, 2 Bass amps, a 4 channel highs amp and then their friend tells them they need a capacitor.  They come in while the build is underway, we tell them that we do not sell them.  He asks why not, we answer: because they do not have any audible or electrical benefits for your system.  We really try hard to convince them, they usually go down the road and purchase one, then bring it to us to install in their car.  We do that then the very next morning, like clockwork, they drive into the parking lot and get out and are mad at us because their lights were dimming when the bass hits. 

I have no idea how much money we have lost out on by not selling them a capacitor, but we refuse to become part of the game that the reps have started. 

Another key part of the equation, the judges are always telling you that if your deck has __ volt preouts you will make more SPL.  Guess what they sell radios too. 





Posted By: oldspark
Date Posted: August 13, 2010 at 10:51 PM
How cynical Idiot! Surely people and companies wouldn't take advantage of people merely to make profit? (Maybe that's why I grew my own pots.)

There is the argument "give them what they want".
It used to be "the customer is always right" but I prefer "the customers are dikheds" - but NOTE - I'm talking of my local situation where people flock to buy capacitors, yellow tops, dc-dc converters (to charge aux batteries), "smart" isolators etc etc.   


At least caps have their purpose, but what I say is that if you need a cap, use a (small AGM) battery instead - it's cheaper and far more effective.
Yes - the solution is with proper distribution and probably a local big AGM (leaving the normal cranking battery as is) and a suitable alternator.
But even then, the caps have their validity - sometimes ever over a battery (in the same location).   


And I think we all know, one reason to include a cap is to REDUCE the SPL, so not selling caps to SPL competitors is the right thing to do. (Though then it's better selling them a HUGE cap that requires pre-charging, then leave the pre-charger in circuit. You make money, they have their essential bling so their mates don't laugh, and they win the comp.)


Anyhow, I'm off to find a smoke. I'm suffering a cold and I have a medical report here that says how tobacco helps....




Posted By: spanyerd
Date Posted: August 14, 2010 at 3:13 AM
oldspark wrote:

   
Anyhow, I'm off to find a smoke. I'm suffering a cold and I have a medical report here that says how tobacco helps....


Funny stuff there.

Grow your own tobacco too?

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Got a burnin' for some learnin'.




Posted By: oldspark
Date Posted: August 14, 2010 at 10:55 AM
spanyerd wrote:

Grow your own tobacco too?

Don't be silly - that'd be illegal! posted_image





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