Has anyone installed a Capacitor in their audio system?
 

-I'm trying to chase something down:

When I crank up my stereo, engine running at normal RPM, when I get a bit of bass in one of the songs, I can see my instrument lights flicker. What is more, I have installed a dash-cam just below and to the left of my rear-view mirror. The first one I installed died. I bought a far more expensive model on eBay, and it didn't work. It seems that the first time I pressed the brake pedal down, the unit would shut down and then reboot!

huh? :eek:

Well, in conversations with the man in Texas who sold it to me, he came to the conclusion that my system voltage was too low. I did a check with a multimeter, and indeed- at the lighter-socket, normal system voltage was about 12.58....but dropped to 11.7 as soon as I pushed the brake pedal down! That was enough to apparently cause the cam to shut down.

Hmm-! Yeah, that lighter socket must have a problem, I thought. And I was correct: When I checked the battery voltage, multitester prongs BURRIED into the poles at the battery....engine off it was 11.9. Engine on it was 13.7. There was no lasting change when I had someone push the brake pedal down.

Diagnosis: Bad lighter socket.

OK....A few weeks ago I pulled the car apart in the driveway and spent an hour wiring the dash cam DIRECTLY into the fuse box. I bought an auxiliary fuse input over at Advance auto, and rigged the cam to fuse #2, which is the fuse that handles the lighter. For a few weeks this worked fine, but lately what I've noticed is that the cam gets a power disruption, and/or sees low voltage again! After I mounted the power supply direct to the fuse box, I noticed that the cam would shut down and reboot when I put the lights up. Big electrical draw, apparenly the voltage dropped.

Hmmm-

But these days, the cam is acting exactly the way it did when I first installed it. Which of course leads me to believe that something is changing my system voltage, and I can't find it. At the battery, I still have 11.9 and 13.7 or so engine off/on.

Bad battery?

Failing alternator?

Ideas:

N-

Possibly both, so, charge the battery with a charger and after 3-4hr with everything off it should be 12.5 volts min. with engine running you should have 14 to 14.5 at the battery.
Now I have been told that with the bosch alternator you need to have it above idle.
now if it is fully charged (checking at the bat) have someone flip the park lamps on, engine off, if it drops quickly to around 11.5 or gets that low within a minute, she needs a new battery.
If you have an older car check the forum for the alt upgrade to a delco. sucks to be me because mine is a 89 and i believe the alt mounting is different. you want 130amp alt on something with any kind of stereo or bright lights.

opinions vary on what is exceptable.

I've been thinking about installing a cap, too. My electrical system is screwy, too.

I was also thinking about a capacitor, then I remembered I understand electricity and lost interest.

How do you install a cap?

N

In series with a load, like an amp.

Like this picture. You just put the Cap on your Head.

http://image.made-in-china.com/2f0j0...seball-Cap.jpg

How about a Video how to?

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You might try connecting your radio to a dedicated line with say #12 or #10 wire to the battery. Sounds like a voltage drop. Don't think a capacitor will solve your problem and you would need a very large one as well. Check your voltage at the radio under a strong bass as you pointed out.

A capacitor is installed in parallel with the power leads near the amp, it isn't connected to the signal or speaker leads at all.

Yes, true but I don't think it's going to solve his problem but he can try it. He would need a large one 50,000 mf or something, usually big "can" looking ones. I have a bunch here mostly used in DC power supplies. The caps you see on the speakers are for frequency cross over reasons. Actually the battery itself acts as a big capacitor. He seems to have voltage drop due to losses in the wire from the battery to the radio I would think. That is the best way to fix it, run a bigger wire through a heavy duty relay and fuse to the battery.

He's got power issues. I got the same symptoms and I am running a nice big power cable from the battery to fuse to Amp. When it hits Bass, my volt gauge jumps like a Crack Monster. It will even turn the amp off for a little while. I am pretty sure my crap rebuilt ebay Alternator is my issue. This is only when I am at slow RPM's. On the freeway, I am a Bass jamming fool. I ordered an overdrive pulley for my Alternator as a last ditch effort to save my Alternator. If that fails the test, I'm going Delco.

Is the battery charged to begin with? What is the condition of the battery? Are you running a completely isolated wire to your radio from the battery? And, of course how is your ground return condition to the battery? How much power does your amp draw? People are putting in KW amps in their cars, that takes a lot of power especially on peak signals. Watts is watts now matter, the power source. What is the static condition of your battery? With the engine off and just running the radio do you have the same symptoms just with the radio on and volume cranked up? You might just be exceeding the amp draw of the battery when all other circuits are operating and driving the radio hard.

I removed all my fuses today and scrubbed the contacts on the EC with WD40 and a wire brush, then installed new fuses, save for ten because I ran out of replacements. I'll buy more tomorrow.

My wavering voltmeter gauge seems to be indicating proper voltage. It doesn't do anything screwy now. Very stable.

After I replaced the engine ground strap a few days ago, the tach came to life and worked great for a couple of days, then went back to it's previous intermittent state. After cleaning the EC and replacing almost all of the fuses, the tach came back to life again, and worked great for about twenty miles, then quit again. A mile later, it came back to life and worked the rest of the trip. I hope it keeps on working.

The tach gets it's signal feed from the distributor, right? If so, I want to clean that end of the circuit, as well.

Welcome to 928 ownership!

So long as they run, I hardened myself to not care about the peripherial stuff.

You know, just a few SECONDS before I posted that today, it occured to me that one of these guys are going to post something that shows how to put a "cap" on.

-In the name of humor, I decided NOT to go back and change the word "cap" to "capacitor", just because I think there is a need in the world for MORE humor, not less!

[sorry to turn this into something that really ought to be on the OT section~]

GOOD show!

N!

I'm not talking about the stereo at all, which is a fairly cheap item with NO amp!

Battery: I charged it today. It is in great condition, only about 2 years old, and YES it is the correct size- 49.

My voltage gauge jumps up and down at stoplights with my turn signal on, yet when I test the battery AT THE TERMINALS, both engine and no engine....it checks out perfect. And the system voltage is correct: At the battery, there is a consistent 13.7 volts engine on. With ALL the lights on and the AC cockpit fan at MAX...even with the brake pedal pressed there is 13.7 volts. Ladies and gentlemen, my original, 25 year-old alternator is working just fine. And my battery is perfect too. Yet, I am getting voltage fluctuation.

[as per Jean Luc Picard...]

"Suggestions?"

N!

PS: I personally think that the voltage regulator is going south. My alternator is 115 amps; I don't know how that couldn't be enough. The Delco alternator that can be modified to fit is actually a Motorola unit just like the original- it was just designed for the 60 degree V6 Camaro and Firebird from 1988. For some reason, I thought that the Delco is actually a 115 amp unit, which makes it a good upgrade for the '84 and earlier cars which had the Paris-Rhone alternator.....which was not only weak but also unreliable. I had no idea that this Motorola alternator was now 130 amps~

N!

So, HOW does one actually install a capacitor? I'm sure it has to be spliced in some place. Where? What wires actually mount to the thing, and what else is needed?

N

There are many types, sizes, voltage ratings of capacitors. The one you would possibly use is an electroletic type to store energy. It would have polarity + and -. The + goes to your positive 12 volt and - to ground. You would wire it in at your radio feed point, where ever it's hooked up for power. You would want a fairly large capacitor for what you are trying to do, but I don't think this is your answer to the problem. Usually capacitors in this case are used for spark/interference suppression and not for power storage. They are used to "clean up" the DC feeding the radio. Capacitors have many different applications and uses in electronics.

Normy - well your issue won't be solved by a capacitor. You have a connection issue somewhere, quite possibly in the ground return lines rather than the power feed lines.

I'd clean all the connections to the CE panel and the grounds, e.g. at the front jump post and possibly alternator and starter.

If you did want to install a capacitor you need to install it as near as possible to your big consumer - usually the amp. It will only help with brief high transient loads -(e.g not with your brake circuit).

Here is an example of my capacitor install for my audio. It is a 0.5F capacitor (500,000uF). This mounting location is quite insanely tight - I'd not realy recommend it to most... you have to do a lot of fabrication.

My amps are located on my the rear seat backs so this is a great loaction for that - possibly also good for spare wheel well mounted amps...

Ideally you have a capacitor switch and charging mechanism. The capacitor is just mounted across the supply (in parallel to the battery - but very local to the amp) use big conductors to the capacitor and to the amp (8AWG is OK, 4AWG is good).

http://www.moore-fun.net/images/Porsche/DSC00195.JPG

Alan