Like

Are there any brands of Capacitors to avoid?

 

Unregistered guest
I'm looking for a 1-farad and a 1.5 farad (for a T1000bd and T15004, respectively) Royal Red, Monster Cap and Stereo Xtreme are the cheapest on e-bay. Would any of these 3 be fine? As long as it works well and is long lasting other feature's don't mean too much to me.
 

RERT
Unregistered guest
All caps are basically the same...companies just stick their logos on it. But i'm not a fan of capacitors cause it's basically a small battery, while you can get a yellow top battery for a little bit more.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1873
Registered: May-04
Not a lot of difference in caps. They're a very simple electrical device. There's not much to screw up.
 

DumbfoundeDave
Unregistered guest
OKay, thanks. I'm running 2 rockford fosgate T1's with 600 rms each, would the caps be enough or do i just need a new alternator or both? Where could i get a new alternator at that would fit my car. '93 buick park ave ultra
 

DumbfoundeDave
Unregistered guest
And with those 2 amplifiers, how many amps would the alternator need to have if I do in fact need to get a h.o. one. Annoying as all heck with these questions ain't I?
 

DumbfoundeDave
Unregistered guest
And with those 2 amplifiers, how many amps would the alternator need to have if I do in fact need to get a h.o. one. Annoying as all heck with these questions ain't I?
 

Bronze Member
Username: Sas

Post Number: 39
Registered: Sep-04
DONT GET A CAPACITOR. all they do is act as resourvers of power. when the cap runs out of power then what will happen? well your cap will start to recharge. to recharge it has to draw the power from the alternator. while it is taking current from your alternator your amp will still need power so it can power the woofers. so while the cap is charging and drawing power off of your alt. , your amp will also be drawing power from your amp.. best thing to do is use your cap money and upgrade ur alternator. all the cap does is cover and hide the problem. the probelm with your car is that the alternator is not producing enough power for the car and your speaker system. to solve the problem all you have to do is get an alternator that will produce the power you need. common sense
 

Unregistered guest
So how many amps would the new alternator need to have? I found a 200 amp one for $169 plus $10 S&H. Would that be good enough, or there was also a cheaper one but it was 105 amp which is more than I have now. And to think all this started when I walked into a best Buy and looked at their subwoofer's thinking "that'd be nice". Nice maybe, but more complicated than heck.
 

Silver Member
Username: Pat_l

Tucson, AZ USA

Post Number: 613
Registered: Apr-04
Sweet system, i am a big RF fan. Way to go!
 

Silver Member
Username: Southernrebel

Louisiana USA

Post Number: 208
Registered: Mar-04
get the 200A alt...you wont reget it!
 

Unregistered guest
So the 200 will be enough with those two amps and 2 t1's with 1200W rms power? Just checkin'. I'd hate to order it then find out i needed a little more.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1887
Registered: May-04
You are lucky enough to find a 200A alternator that didn't have to be custom built. But yes, you'll have plenty of charging power from a 200A alternator with 1200W RMS.
 

New member
Username: Ericaraudionut

Post Number: 5
Registered: Sep-04
hi everyone, just alittle something to add. even with that 200a alt. you may want to consider a small cap. it's going to regulate your voltage, you don't want fluctuation. you should be able to get a flat 13.8. and a cap could insure that.
 

jeremyh01
Unregistered guest
Hey guys,
The capacitor is nothing like a battery! It operates very differently(creates a potental difference =>difference in charges...batteries are slow inproviding power through a chemical reaction). Capacitors are Instantaneous in the delivery of current and are very beneficial to hungry power hungry audio equipment. Basics-> Capacitors store electrons to be released at any time when the current from the battery is insufficient to power the requested output(amp needs more juice instantly). The battery and cable are the limiting factors. A capacitor helps relieve that need and increases output. electrons move at nearly the spped of light so there is next to no wait in charging. run a nice gauge cable with a capacitor and your amp will never go hungry for juice. alternators just maintain the battery and don't directly power your equipment. Do you homework guys. You could all benefit from a stiffening cap.
Jeremyhdz
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1899
Registered: May-04
"run a nice gauge cable with a capacitor and your amp will never go hungry for juice"

You forget that the alternator also supplies the current for the cap. How do you think a cap maintains a charge? If the voltage of the system drops, the capacitors reserve will drop as well. A capacitor will aid in peak draws and transients, but it won't replace the need for an alternator. To quote Glasswolf:

A capacitor WILL:
-Stiffen voltage rails. If you experience very brief, momentary periods of high current demand that cause the electrical system to falter only at these rare, peak draw times, then a capacitor will supply the additional current needed (when bass hits) to keep your voltage rails stiff, and prevent damage to the car or audio equipment.
-Increase response times for musical accuracy by reducing delay caused by transient response times between current demands from the amplifier, and response to this by the electrical system. In other words, your subs will respond more quickly, because they don't have to wait for the alternator to supply additional current at the moment of demand. Amplifiers have to provide a very dynamic and quick response many times. A capacitor can assist in this if the rest of the charging system is up to par.

A capacitor will NOT:
-replace the need for a larger, high-output alternator and/or a deep-cycle battery or batteries.
If your electrical system is inadequate, the ONLY way to fix this, and again I repeat, the ONLY WAY to fix this, is to replace the alternator. This is the SOLE source of electrical current for your car when the motor is running.
When the motor is turned off, the battery then becomes your source of electricity.
When the battery is run down, and when the capacitor(s) is/are depleted, the alternator has to work even harder in order to supply current to the car, the audio system, and also to recharge the capacitor(s) (which deplete very quickly) as well as recharge the car's battery(ies).
So by adding a capacitor to try taking the place of a high-output alternator, you are actually causing more work for your alternator, and causing even more damage to that stock alternator.
-make your system magically sound 10 times better.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1900
Registered: May-04
With that in mind, you can then choose what your system needs. I would only recommend a cap after your charging system is up to par.
 

New member
Username: Protrex

Post Number: 1
Registered: Sep-04
I am installing a system in my 1992 Toyota Camry. It has a 70AMP alternator stock, I ordered a re-engineered 150AMP alternator form mralternator.com. I also ordered a diode Battery isolator to put under the hood and an Optimum Yellow Top battery to put in the trunk with my amps. 4 Gague will go between the battery isolator and the battery in the trunk, 8 gague will go from the battery to the amps. I will be running two JBL amps for approximatly 1000W of RMS power. Do any of you think that I will need a stiffening cap with this setup?

-Jamie
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1916
Registered: May-04
The alternator should deliver the amount of current you need. A cap can help aid in transient response, but whether you would notice a difference is negligible.
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 239
Registered: Sep-04
I've got PPI pro Mos-2050(400 watts) running a pair of 10w3d2's. I added a Tsunami 2 farad cap and love what it did for my system. I listen to a lot of classic rock(Pink Floyd, Phil Collins, etc) and its amazing how "hard" the drum hits are now. I have a 170 amp alternator installed and if I let the car run at idle(70-80 amp output from alternator) with headlights and a/c on the cap does nothing. My in dash voltmeter bounces around and my dome light dims pretty bad. The alternator just never gets a chance to charge up that cap, but if I rev it up a bit the voltage goes rock steady again.

Caps are great, but alternator comes first.

-Fishy
 

New member
Username: Mememegetgetget

Post Number: 10
Registered: Sep-04
"electrons move at nearly the spped of light so there is next to no wait in charging"

Next to no wait my @ss.... I'll agree that caps DISCHARGE in no time at all, but charging is not instant, think about your little kodak flash camera... when you are waiting for your flash to charge up, that's a capacitor in there charging.....
 

Bronze Member
Username: Mememegetgetget

Post Number: 11
Registered: Sep-04
and I know I know, the charge time is also related to the battery, but if your battery/Altenator set up isn't providing the juice for your amp, the cap alone won't solve it, it might cover it up completely if your music generally never hits hard very fast and very repetatively but it isn't a cure to the problem merely a band aid and when you're comparing $100 for a cap vs $260 for a HO alternator in this persons case it's pretty easy to see the better choice....
I recomend Caps, I think they are a great asset to your system, but I take issue with you implying people who thinks caps aren't the answer need " Do you homework guys"..
 

Silver Member
Username: Johnnylemoine

LaPlace, Louisiana United States

Post Number: 125
Registered: Aug-04
i have a '94 chevy silverado, where can i find a high amp alt. and for how much? I have a power cap, 1 farad, and my current alt. is a 105 amp. should i go bigger on the alt., i listen to alot of bass songs like rap and stuff and some rock. I have a punch 150 pushing a JL 12W3D4 and a sony 222 pushing 2 4x6's and 2 6x9's.
O yeah, the truck is power everything: locks, windows, cruise, a/c, etc.
 

Silver Member
Username: Zacdavis~

Post Number: 137
Registered: Sep-04
i gained 1.2 db using a 50farad hybrid cap:-)
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 245
Registered: Sep-04
Do you have in dash voltage(battery) gauge on that Silverado? I wouldn't think those two amps would be that much an extra load for a 105 amp alternator, but if you have an in dash gauge you can check that pretty easily. Run your engine a bit above idle, say 1200 rpm or so and note the gauge position with headlights and a/c on. Crank your system. If the voltage drops a good deal and doesn't recover you might benefit from from a higher output alternator.

I got a 170 amp alternator for my Explorer for $180 shipped here.

http://motorcityreman.com/

I've had it for a couple months now and aside from a lil pulley/belt "chirp" when cold I'm completely satisfied. My new alternator came with a substantially smaller sized pulley so I guess that was to be expected. I tightened the belt tension a tad and although it still squeaks occasionally the problem is pretty much gone.

Being a remanufactured unit the alternator had the exact same housing as my stock one and basically plugged right in. Took about 30 mins to install.If you're shootin for an alternator in the 160-170 amp range I don't think you can beat these guys pricewise.

-Fishy
 

Silver Member
Username: Johnnylemoine

LaPlace, Louisiana United States

Post Number: 127
Registered: Aug-04
Thanks Fishy, I do have an in dash voltage meter, when i am idling and listening to music, the meter goes down to about 10 volts and does not recover good, but when i am driving with a/c and lights on it drops to about 12-13 and still bounces a little when the bass hits. It ususally runs at 14 with out lights, a/c, and music.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1962
Registered: May-04
You need an alt then. Sounds like you're just pushing the limitations. That 170A Fishy showed you will work great, I believe www.mralternator.com has a 200A for Chevys also.
 

Silver Member
Username: Johnnylemoine

LaPlace, Louisiana United States

Post Number: 128
Registered: Aug-04
thanks Jonathan, you da man.
 

jeremyh01
Unregistered guest
Hey Guys,
I want to start by saying that i meant no harm, or disrespect and didn't want to sound insulting with my comments. jonathan is correct when he says that a capacitor will not fix an inadequate electrical/charging system. That should have been considered first when ugrading beyond stock or factory components.For those who didn't.....homework. He is incorrect in saying that the alternator is the sole source of current when the motor is running. he is also incorrect in saying that it charges the capacitor. the battery does this. The battery supplies the juice and is maintained by the alternator through the voltage regulator. Want proof, disconnect you alternator and the engine and all your components will work. You can turn your car on and off and play your radio as loud as you like but will quickly drain the battery. Without the battery, you wouldn't be able to even start the car or listen to the radio. once started, the battery can be disconnected but the current delivery will not be as consistent because this is dependent on the rpms of the alternator.
I will say again,the alternators main purpose is to maintain the charge and then aid in current delivery while running. --> I don't recommend that you all try this disconnecting stuff because it can cook some of the "newer" electrical circuits but its true. Ask any mechanic who knows.
There is a flip side to the high amp alternators though. continuosly overcharging a battery mechanically ruins it internally and over the long term kills your battery. Electrolysis is the chemical process that "charges"(mechanically rebuilds the cathode and anode plates) the battery and to much overcharging can create an internal short circuit--> dead battery. If you have a killer system and really stress the electrical, get the alternator.
The "do your homework" was for those who said that the stiffening capacitor was like a battery Jim. And as for the waiting for charge to build up on your camera has to do with the capacitance area(l x w) as well as the potetial difference applied to it. Those cameras have super small capacitors (micro, pico farad) and have a small potential difference applied. Check out the guys who can afford those killer camera setups that have seperate flashes and battery packs. The have the larger area and the larger potential difference. They can flash you till you go blind. oH yea, those of you who think you pusing all those amps from the alternator, your doing it only part of the time. Most high amp alternators are only slightly better than stock at idle but really blow away the stock alternator at their certain designed rpm range. you only really get those extra amps when your revolutions are up.

Jonathan is right! add the cap if you need after you have taken care of the weak electrical system.
Jeremyh01
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2013
Registered: May-04
"He is incorrect in saying that the alternator is the sole source of current when the motor is running. he is also incorrect in saying that it charges the capacitor. the battery does this. The battery supplies the juice and is maintained by the alternator through the voltage regulator."

The battery won't charge w/o the alternator, making the alternator the "heart" of the system. You're taking the way I phrased it a little too directly. w/o an alternator a battery and cap will discharge, making the alternator the most important upgrade. The battery is what transfers this power, but it's simply a chain. I think you know that's what I meant, I'm not that much of an idiot :-).

"And as for the waiting for charge to build up on your camera has to do with the capacitance area(l x w) as well as the potetial difference applied to it. Those cameras have super small capacitors (micro, pico farad) and have a small potential difference applied."
It's simply b/c of the voltage. A smaller capacitor will charge more quickly than a larger one.
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 290
Registered: Sep-04
whoa whoa whoa

How is it possible for current to flow from a lower potential voltage to a higher one?

If your alternator is providing a steady 14 volts to both your cap and battery there's no way I know of that your battery could be doing anything but "accepting the juice" from that 14-12(or whatever your battery is at) voltage difference.

And when it comes to DC circuits a capacitor IS analogous to a battery. They both are energy resevoirs. They both can be considered voltage sources if their "internal" voltage is higher than that of their outputs or voltage "sinks" if that same "internal" voltage is lower.

The only time a battery provides current is when the alternator output AND that of the cap falls below 12 volts or whatever the "internal" voltage of that battery is such as when you shut the engine off or when your amps/headlights/a.cond are demanding more current than the alternator can provide. Likewise the only time a stiffening cap provides current is when the voltage provided by the alternator falls below its "internal" voltage like when you get a quick current demand from your amp that your alternator can't deal with. Once your cap's potential voltage falls below that of the alternator it then "sinks" current just like your battery does. It just charges up a helluva lot quicker.

I dunno, maybe I'm wrong(my terminolgy probably is subpar), but I've taken quite a few EE, Electronics, and Acoustics courses in my failed 8 year quest to get a Aerospace/Ocean Engineering degree. Regardless, thats my take on this alternator/battery/capacitor controversy.

Wish Glass was here to a definitive treatise on the subject.

:-)

-Fishy
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 291
Registered: Sep-04
...Glass was here to *give* definitive treatise...

Sure suxxorz not being able to edit these things. :P
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2022
Registered: May-04
"How is it possible for current to flow from a lower potential voltage to a higher one?"
It can't

"The only time a battery provides current is when the alternator output AND that of the cap falls below 12 volts or whatever the "internal" voltage of that battery is such as when you shut the engine off or when your amps/headlights/a.cond are demanding more current than the alternator can provide. Likewise the only time a stiffening cap provides current is when the voltage provided by the alternator falls below its "internal" voltage like when you get a quick current demand from your amp that your alternator can't deal with. Once your cap's potential voltage falls below that of the alternator it then "sinks" current just like your battery does. It just charges up a helluva lot quicker."
The battery is always the source of electricity. Current comes from the battery, but that's because it's part of the chain. The alternator doesn't directly power the system b/c it's not on all the time, it simply provides a voltage bias in order to keep a charge. The reason I call it the sole source of electricity is b/c it is the supply for the system. W/o the alternator, the system would eventually die. The voltage regulator will trip on and off, when it's off, the battery is the source of electricity, as when it's on. The battery becomes the sole source when the alternator is either off or doesn't have enough charging power to create a bias.

For those who don't know how these work (not talking about you, Fishy)I guess the easiest picture is to say that the alternator is like a water supply line, the battery is a pump with a reservoir, and a capacitor is a reservoir with a dump valve(dump valve is capable of emptying faster than the supply fill it up). When the supply is fully running, the reservoir w/ valve and pump's reservoir stay full and all flows well with a consistent water level. When the supply cuts off or can't keep up, the reservoir w/ dump valve will supply water out of it's own sources, and the pump reservoir will pump into the dump valve and slowly lose it's level until all water is gone (dead battery). So you see, the pump reservoir is capable of suppling the lines with water by itself(without source) but without the source it is incapable of maintaining this system.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2023
Registered: May-04
I guess it's just a terminology thing. The alternator could be considered the supply, but w/o the battery, you wouldn't have electricity. That's why you say that current always comes from the battery. Kinda like the water example above. Current for batt comes from alt., capacitor current comes from battery, amp's current comes from the capacitor. Just b/c they're in series, so I guess you'd say the closest component to the load would be considered the "source" of electricity to the load, the battery is the only thing that can supply current from it's own sources. Kinda like the water always comes from the pump, but that water wouldn't be there without the supply.
 

New member
Username: Stanleyc

Post Number: 4
Registered: Oct-04
Anybody know where I can get a HO alternator for a 240sx that has more than 150amps. mralternator.com only has 150amp alts for nissan.
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 315
Registered: Sep-04
Nah, the source that has the highest voltage potential or bias as you put it is what provides the power or "water". Think of that red power wire that goes from your alternator to your battery, to your cap, and then to your amps as a river. Then imagine the alternator as a high volume/pressure pump, the battery as a high volume tank, the cap as a low volume tank(with dump valve), and your amps as firehoses.

Now think of the water flow as current(hmmmm.... :-)) and voltage as water level or "head" as it is referred to in hydrodynamics. Whatever location has the highest level or head(pump pressure counts as head btw) will be what is providing "water" to this river just as whichever component(alt, cap, or battery) that has the highest voltage will be providing the electrical "current".

If either the cap or the battery "resevoirs"(another hmmmm.... :-)) fall below the level(voltage) of the river it gets filled up with water(electrical energy) or conversely dumps it during droughts(alternator at idle maybe?).

You see it doesn't really matter who provides energy faster just who has the most potential.. err... energy. Your battery and cap both act the same. One just has the ability to reach a higher voltage and charge and discharge a minimal amount of energy at a very high rate(cap), whereas the other although having less potential voltage and a slower charge and discharge rate has a huge of amount of storage space comparatively speaking(battery).

One thing I didn't know was how a voltage regulator worked. Now that I have some idea i can see why its absolutely necessary to have a battery in the system although it would seem a HUGE capacitor bank could work just as well.


-Fishy
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2029
Registered: May-04
See, now you had to get all technical on me and use better analogies :-) lol j/k. A voltage regulator is very simple actually. It simply sends a signal to the stator(coil windings) of the alternator. The rotor begins inducing current in the windings, thus a charge. If voltage goes above a set point, it stops current going to the stator and the alternator stops charging.
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 320
Registered: Sep-04
hehe, yeah that was a fun exercise that really just modified your analogy a bit.

So is the voltage regulator just a "switch" that momentarily cuts(or shortens?) the circuit of the windings? or is it a "backwards emf"(electromotive force, sry kinda technical) that applies a reverse voltage bias to knock the voltage down.

If its a "fast" switch I can understand why you'd have to have a battery to power your amps( a voltage base when the alt. is totally "off"), but if its just applying a reverse voltage it seems like you could run your system with the alternator alone.

On second thought I guess it'd have to have a lot of power potential to apply a sufficient reverse bias and that would have to come from somewhere like maybe the battery? :-)

think i'll go googling

-Fishy

 

jeremyh01
Unregistered guest
Hey jonathan, Your not an idiot! you've got the idea. The truth of the matter is though that the battery is nothing like a capacitor guys. Want proof! Grab the posts of a battery, one in each hand. What do you feel? Try it with wet hands. Try it with a minor scrape or cut on your fingers---->nothing you can't really handle(don't drop your resistance to much).
Now Try touching the terminals of a fully charge capacitor....You're dead! really!..Batteries contain only chemicals and metals so the current delivery is governed by the rate of the chemical reaction. They don't hold a charge. they just hold chemicals that have a potential difference
A capacitor on the other hand holds a charge(only device that can by the way-> other then a lyden jar), transfers only the electrons needed to achieve an equilibrium in charge. Trouble is that is does this at the speed of light...even through and over you body. ---> DEAD! They are very high amperage. the body can handle thousands of volts but not much more than .5 amps. true! if you had less resistance, you'd handle even less. thank God for tough skin huh.
The current for the bat. does not come from the alternator though. the battery has its chemicals that generate juice. the alternator helps reverse the reaction in the battery so that its reaction doesn't run to completion.
The regultor simply blocks the flow of the current when necessary (through use of diodes and such). the permamnent magnet "induces" a current in the windings. magnetic fields induce current in a wire just like a wire carrying a current has a magnetis field.
you are right though, it is a technical word, word play. but you have to be technically right when it comes to electricity. one error and poof!
see you all later
Jeremyh01
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 321
Registered: Sep-04
Is this "series volatge regulator" the type used in automotive applications?

http://www.tpub.com/neets/book7/27k.htm

I guess the zener diode sets the base voltage of that transistor and the transistor seeking a .7 volt emitter bias acts like a variable resistor that adjusts its voltage drop relative to the unregulated input voltage. uhgg.....

Other than needing the battery to crank up your car I still don't see why the the alternator can't be the sole source of power for your amplifiers, etc. In other words why couldn't you just simply disconnect the battery once your car is running? What would happen?

-Fishy
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2035
Registered: May-04
There were different types of voltage regulators through the years, but most of them simply short out the alternator so no current is produced. For example, the first regulators were "shunt" regulators and were used back in the 60s when alternators began being used(and before that they were used w/ generators), it used a ballast resistor to dissipate power (those regulators had a HUGE heat sink) and the rest traveled to ground, shorting the output. Relays were what triggered contacts by the relay coil's temperature, and that controlled the voltage via contacts. Newer designs went to solid state, most are switched mode power supply type regulators, using transistors as switching devices to turn the stator on or off. It uses a feedback circuit and compares output voltage to the reference voltage (set via potentiometer or other means) and this is what switches the mosfets on or off if necessary. SMPS regulators are much smaller and produce a lot less heat, which is why now regulators are typically integrated w/ the alternator.

About the above, It's difficult to put into words b/c the battery and alternator are connected in parallel, anything connected past that point will use the battery as reference (simply, the battery isn't the supplier of current, it's just the point where all current comes from because that's what the alternator is connected to). BUT being a parallel circuit, power can come from either depending solely on if the alternator is charging or not, if the alternator is on, it uses the battery simply as a direct connection to the rest of the system. If it isn't charging and your bass hits, that comes from the battery temporarily until the regulator kicks in. But since it's parallel, when the alternator is charging, the battery is considered a load to the alt. and everything is powered by the alternator. I guess to describe it, the battery is the "reference point" that all power comes from, but the battery doesn't provide it from it's own sources until voltage goes below the alternators range (or if the alternator is disengaged).
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 322
Registered: Sep-04
err.... jeremy for your information ALL electrons travel at the speed of light. It doesn't matter if they're comin from a battery, capacitor, coil, alternator, or whatever......

Its true that curent is what kills, but voltage is what facilitates the transfer of current.

Did I ever tell you the story bout the guy who sat down on a marine starting battery after waterskiing in the Intracoastal Waterway(saltwater)?

-Fishy
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 323
Registered: Sep-04
So today's automotive voltage regulators are simply solid state switches which simply "remove" or isolate the alternator from a car's electrical system when the voltage gets too high.

That about right?

-Fishy
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2037
Registered: May-04
Can't remember if series regulators were used (probably were) but to answer your question, yes the alternator COULD be the sole source of current, I say that meaning it is capable of providing the necessary current, and yes your engine would still run. And usually, it is the sole source, except the VERY brief periods that the regulator takes a little while to kick in. But you couldn't disconnect it b/c it would have voltage spikes, destroying the regulator and every other piece of equipment it leads to. The alternator is either on or off, floored or stopped. Since the regulator works as such, the second you had current draw, the voltage would shoot through the roof, then totally stop when all current demand stopped. Without storage, the alternator would have to be on constantly, meaning you'll overcharge. The battery helps to regulate the voltage that your equipment sees b/c of it's storage capacity, similar to how a capacitor helps when rectifying 3 phase outputs, it will discharge it's stored current during the brief periods that the voltage drops and rises. It smoothes out the spikes simply put. If the battery wasn't there, the electronics in your car would be subject to a constantly changing transistor output, and since these components (audio especially) don't steadily draw current, the regulator's kicking on and off would be so inconsistent it wouldn't even be funny, voltage would be sporatic. It'd be different if you had a consistent current draw and an alternator perfectly matched to provide "X" amount of current, or a regulator that was capable of actually cutting voltage to a set level, but since it's either on or off, you would get the alternators full power capability all the time, which wouldn't be good when you only need x amount of amperes.
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 324
Registered: Sep-04
So the battery acts as a fairly constant "load" or base which smooths out the voltage. Yeah that makes perfect sense if the regulator is just a pure on and off switch. In order for your alternator to power everything you'd need somethin like that "series voltage regulator" which "gradually" regulates the voltage.

I guess todays regulators must "switch" awfully fast. I took my little voltage gauge off my cap(what a stupid place for a voltage gauge) and mounted it in the 1/2 din space under my h/u. My Explorer's regulator must do the switching thing very quickly or it seems I'd be able to notice the drop from 14.5 - 13.5 volts(or whatever the batteries at internally). When I turn everything down/off and rev up the engine that voltage stays rock soilid at 14.4 - 14.5 volts.

There is a very annoying beeping that comes from my gauge when it stays around 14.4. Guess thats some sort of over-voltage warning. May have to take the dykes to those lil "beeper" chips.

:-)

-Fishy
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2038
Registered: May-04
"Batteries contain only chemicals and metals so the current delivery is governed by the rate of the chemical reaction. They don't hold a charge. they just hold chemicals that have a potential difference"
You've got that backwards. The charge is already there. When the materials are assembled in a battery, the reaction instantly takes place, it doesn't gradually happen. Depletion of charge is when things change. When the alternator provides a bias, the bias is maintained within the battery so that this chemical reaction remains there. Voltage is always there as long as the load hasn't drawn all charge from the battery. The plates contain chemicals that react with certain types of metal, but since each plate is positive or negative, it is considered charged because potential difference is there. It's not the chemicals that hold the charge, it's the metal used. They use a specific metal(spongy metallic lead for the anode, lead dioxide for the cathode) and when the chemical is applied, the charge instantly happens (like magic :-)) because they remove either protons or electrons from the metal (depending on which cell you're talking about) resulting in a charge. Anyway, when you draw current from a load, you're not waiting for the chemicals to react, it's simply because of the internal resistance of the battery, similar to using too small of a power wire.


"The current for the bat. does not come from the alternator though."
Technically it does when the engine is running, simply b/c of the voltage bias provided to the plates. If the alternator was disengaged the battery would eventually lose charge. Anytime the voltage is below or at the battery's internal voltage, 12V, then the current comes directly from the battery because the alternator isn't creating enough bias to overcome the batteries internal resistance. When the alternator is running, the battery is actually a load to the alternator, and current basically goes straight past the battery because the alternator is the point of least resistance to the electrical components. Of course, the voltage bias simply creates electrolysis on the plates, but if it didn't "come" from the alternator the bias wouldn't be there. Batteries are a chemical reaction, but it is the alternator that maintains this reaction and keeps it from stabilizing. So technically, the alternator isn't what made the battery have a charge in the first place, it maintains the charge that the battery currently has by creating a bias to overcome the batteries own internal resistance. Terminology thing.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2039
Registered: May-04
"So the battery acts as a fairly constant "load" or base which smooths out the voltage. Yeah that makes perfect sense if the regulator is just a pure on and off switch. In order for your alternator to power everything you'd need somethin like that "series voltage regulator" which "gradually" regulates the voltage.

Yep. That series regulator wouldn't work well because any extra power would have to be dissapated in the form of heat in the regulator. That's why we use switching supplies.

"I guess todays regulators must "switch" awfully fast. I took my little voltage gauge off my cap(what a stupid place for a voltage gauge) and mounted it in the 1/2 din space under my h/u. My Explorer's regulator must do the switching thing very quickly or it seems I'd be able to notice the drop from 14.5 - 13.5 volts(or whatever the batteries at internally). When I turn everything down/off and rev up the engine that voltage stays rock soilid at 14.4 - 14.5 volts."

They have to switch extremely fast, far past 20 khz, because anything below that would generate noise in audio components. Faster than the typical car amplifier would, if that gives you a hint.
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 326
Registered: Sep-04
Yeah how much current can you sink(?) through a typical transistor w/o destroying it. That series deal must be used for low power/current apps.

-Fishy
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2041
Registered: May-04
It is. It depends on the transistor how much current they can sink. Just like resistors. They're usually used in the milliamp range.
 

jeremyh01
Unregistered guest
fishy
I'm glad you realize that electrons move at NEARLY the speed of light. Good for You! What i don't think you understand is the rate of electron flow in a battery is limited by the rate in which the tranfer of electrons in the chemical reaction can occur. When they move, they do move at Near the speed of light.
A capacitor has stored charge from electrons already seperated from their parental atoms. They just need to get back to were they came from. They are not dependent on the rate of reation or anything like that. They all transfer immediately at nearly the speed of light. That equals a great flow of electrons almost instantaneously. they don't wait for a thing, just to be connected with a path back home.
simple enough... i thought.
oh yea.. voltage is what they call a potential difference.
Hey fishy, tell me that story anyway. sounds interesting.
jonathan, " the reaction instantly takes place, it doesn't gradually happen." is that right? the molecules involved in the reaction must find the other type of molecules so they can "tranfer" there charge. it doesn't happen instantly.ever heard the term "rate of reation".
they do have a potential difference between them though("they just hold chemicals that have a potential difference." You've got that backwards. The charge is already there".--> I'm glad you see that but the difference in charge IS the potential difference. Who's got it backwards?
oh, and thanks, i didn't know you could remove protons? ....that is without a whole lot of energy and some particle accelerator.-->nice batteries!
" the alternator isn't what made the battery have a charge in the first place, it maintains the charge that the battery currently has"(through electrolysis) Glad you see it. afterall, terminology is important.
catch you all next time
Jeremyh01
 

Anonymous
 
I dont know much about cars but heres my input anyway. from what i understand about the only reason we HAVE a battery is to start the car when it is turned off. I mean something has to get that alternator moving..right?
 

Bronze Member
Username: Heresy209

Post Number: 13
Registered: May-04
I didn't read this whole thing, only about half. I don't know about you, but I've started my car, pulled the battery out and it still ran fine, music, lights, A/C and all.
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 428
Registered: Sep-04
Jeremy your confusing(or confused us with) the speed of an individual electron with the "volumetric" rate or how many electrons/sec are going through something.

Your story about a capacitor is completely valid but probably refers to a cap charged up at a "high voltage". Any large energy storage device, be it battery, a coil, or a cap has the potential to kill but only if it also has the requred voltage to transfer that energy.

No one's gonna die from grabbing hold of the end of an 18v stiffening cap. If someone could do you think they'd let 16 year old's buy em at Best Buy?

Not

No, what is fast about a cap is how quick it can go from delivering 0 current to say 100 amps. Nothing delivers current instantaneously. A cap just makes this "leap" better than a battery. Otherwise they're basically the same animal.

-Fishy
 

New member
Username: Terps297

Potomac, MD USA

Post Number: 1
Registered: Oct-04
Hi, i have 2 Audiobahn aw1251t's (800w max 400rms) and getting a rf 700x or 700s or some other rf amp to power my subs, along with another 150w amp to power my 6x9's. 200w pioneer deh-3400 cd recierver also. I'm getting a 1.5 farad capacitor to help out with 4ga wiring. WILL I have problems in my 92 buick regai???
 

jeremyh01
Unregistered guest
Fishy,
you've got the correct idea but let me clarify what i meant with the "rate" or as you stated, the volumetric rate. If an electron can move form one atom to another, it will do so at nearly the speed of light. that is a given. what i meant when i said rate of transfer in a battery is that the electrons can move at nearly the speed of light Once they have left the valence shell of the parental atom and have another atom to cling to. The trouble with a battry is that the chemicals in them can find only so many of the other kind per unit time to "give or exchange electrons" with. that is the limiting "rate" of electrons traversing a connection per unit time in a battery. In a capacitor, the electrons are ALREADY seperated from the parental atom and wish to get back. remember, nature prefers systems of "less energy". Once connected, the electrons all want to return home at the same time and at the nearly the speed of light. This gives rise to a Huge number of electrons trying to traverse the connection per unit time. That kills!
The reason they sell them to anyone though are because they are not exactly a basic or a true capacitor. they have additional circuits so that people don;t kill themselves. otherwise the companies could be held liable. they make it so you can't so its one less thing they have to worry about. with some tweaking, you could if you wanted to.
So truth be told, a battery and a capacitor are nothing alike. it is a fundamental misconception to believe that they are.
See you all later
Jeremyh01
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2243
Registered: May-04
"The trouble with a battry is that the chemicals in them can find only so many of the other kind per unit time to "give or exchange electrons" with. that is the limiting "rate" of electrons traversing a connection per unit time in a battery."

Exactly, it's limited by the battery's internal resistance, which I stated far above. The rate of discharge you're speaking of IS the internal resistance of the battery, BUT in the car application I was referring to, you should optimally never have to rely on the battery for power. What I thought you were talking about was the rate of charge of a battery at first. I think we're on different pages. I was describing what happens in an application such as a car, in which you're NOT waiting on the battery because when the alternator is charging (which is 99.9999% of the time) it is directly powering the system, and everything, including the battery and capacitor, is a load to the alternator. So yes, the alternator charges the capacitor, and the battery as well. Because the battery has a higher internal resistance than the alternator does, electronic components are naturally going to choose the path with least resistance, via the alternator. Thus, like I said, to supply your vehicle, you are not waiting for the chemical reaction to occur because the alternator is the supply. The battery is considered a load to the alternator, and should optimally only charge, not discharge. Only during those brief periods of time that the system pulls from the battery will you have to rely on it's rate of discharge. The alternator and battery share a parallel connection, so either can supply the system without the other, so saying "That's wrong, if you disconnect the alternator the car will still run" is wrong. The battery aids to regulate the alternator's output, and helps during those periods of time that the alternator is incapable of supplying the required power, such as at idle or when the regulator is kicked in, but during normal driving periods the alternator should always be the sole source of current. Both can supply the system, and rely on each other. But a system running off just the alternator would last a lot longer, because the alternator could supply current forever (at least until it breaks down). The battery is simply the reference point. People can compare a capacitor and a battery all they want to, but in a car application, it's stupid to compare them because with the engine on, the battery shouldn't even power the system. You're really comparing the capacitor and alternator, and when your lights dim, that's that momentary lack of current due to the regulator having to kick in, adding a capacitor only aids this because it stores current and releases it long enough for the alternator to "turn on" and supply the system. The battery doesn't really supply the capacitor unless the alternator is disconnected, anything that pulls current from a circuit will remove electrons from everything, so the capacitor and battery will level off so to speak, but the alternator is what directly charges it. Also, because the capacitor has less internal resistance than a battery, and it's closer to the system than an alternator, it naturally will be capable of supplying the system more quickly, and will charge more quickly. We never stated a battery and capacitor are the same. You stated that the alternator doesn't charge the capacitor, but if it didn't, what would be the point as you'd be relying on the battery, which is slower to charge and dissipate electrons, to charge a capacitor, which charges quicker and dissipates charge more quickly than a battery? You'd be getting nowhere as the capacitor would only charge as quickly as the battery would allow it.
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 506
Registered: Sep-04
C'mon dude, a stiffening cap is about the simplest device you can add to a car audio system. Its just a really high farad, low voltage capacitor. You could make one yourself by soldering a bunch of "smaller" caps together in parallel. There's no "protective circuitry" involved. Its a real easy thing to "weld" one of those suckers to your chassis, but a much more astounding feat to stop a heart.

A charged high voltage ignition coil is another story. Those things can be deadly.

Amps kill, but voltage is what enables current to flow through high resistances like one's skin.

V = IR => I = V/R

Given a fixed resistance, the higher the voltage the higher the current.

Try wiring 50 automotive batteries in series and grabbing the end terminals. It'll light you up.

A common phrase heard in reference to electrical safety goes something like this: "It's not voltage that kills, it's current!" While there is an element of truth to this, there's more to understand about shock hazard than this simple adage. If voltage presented no danger, no one would ever print and display signs saying: DANGER -- HIGH VOLTAGE!

The principle that "current kills" is essentially correct. It is electric current that burns tissue, freezes muscles, and fibrillates hearts. However, electric current doesn't just occur on its own: there must be voltage available to motivate electrons to flow through a victim. A person's body also presents resistance to current, which must be taken into account.

Taking Ohm's Law for voltage, current, and resistance, and expressing it in terms of current for a given voltage and resistance, we have this equation:

I = E/R

The amount of current through a body is equal to the amount of voltage applied between two points on that body, divided by the electrical resistance offered by the body between those two points. Obviously, the more voltage available to cause electrons to flow, the easier they will flow through any given amount of resistance. Hence, the danger of high voltage: high voltage means potential for large amounts of current through your body, which will injure or kill you. Conversely, the more resistance a body offers to current, the slower electrons will flow for any given amount of voltage. Just how much voltage is dangerous depends on how much total resistance is in the circuit to oppose the flow of electrons.


from here:
http://www.ibiblio.org/obp/electricCircuits/DC/DC_3.html

I'd read the whole thing.

-Fishy
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 507
Registered: Sep-04
Sure a capacitor and a battery operate in two different ways but your car's amplifier doesn't know the difference. It draws current from the highest available voltage source, be it the stiffening cap, the battery or the alternator. All that valent and covalent bond terminology you grabbed off the internet somewhere don't mean squat.

All three are just available energy sources. Whichever has the highest voltage potential provides the power. You've just managed to complicate a very simple system that is quite easy to understand otherwise.

-Fishy
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 510
Registered: Sep-04
I'm sorry man, I didn't mean to be rude. I'm sure you know a lot about chemistry and molecular physics. I really don't know much about how a battery operates on a chemical or atomic level. I do know that for most applications it can be modeled as a simple DC voltage source which can provide current to a load defined as

I = dQ/dt

or the rate of change of charge with respect to time.

1 ampere = 1 Coulomb/sec

and the charge on a single electron is

e = 1.602 x 10^-19 Coulombs

So for every one amp of current you have 6.2x10^18 electrons passing thru something per sec.

All of this info is just fine and dandy but its really just easier to just view all these guys as simple energy sources(or sinks when charging).

When it comes to how these sources interact in a car audio application I think you're "missing the forest for the trees" here a bit.

-Fishy
 

New member
Username: Krazy_karl

Kansas City, USA

Post Number: 8
Registered: Oct-04
I just want to say this is possibly the most interesting thread I have ever read on any board at any time. Including Fantasy Football mock drafts in 2002! That's saying a lot.

Props to all who keep this going.
 

jeremyh01
Unregistered guest
Bet your rear Krazy Karl! Some sad stuff huh? before i forget, did you read it all Karl?

Hey don't worry about it fish. You don't sound rude, just misinformed. yup! --> that was not meant to be rude either. oh yea! before i forget, who' looking stuff up on the net?
-->"from here:
http://www.ibiblio.org/obp/electricCircuits/DC/DC_3.html
I'd read the whole thing.
-Fishy"

-->Doin your homework to keep up huh? well, so you know, i don't have to. this is remedial stuff from high school so i'll go over it as many times as i need to.
The "missing the forrest for the trees" is a truly funny comment as your misconceptions concerning individual components aswell as combined components(systems)has proven to be a fatal flaw in your logic.
think about it?
Why in the world would we need Capacitors anyway?
They are a completely different device aren't they? They do(so you know)behave completely different and have very different dynamics. They are simple enough but are extremely different in juice delivery.
Maybe you should try this. Disconnect your alternator. Turn on you system and bump it as loud as you like. Turn on your car. turn up the system. having any trouble? if so, it's due to your weak electrical system... Add a cap. Still no trouble just a little more output when needed (No more laging amplifier)...... now Reconnect the alternator. Now that your battery is in need of charging you can get serious use from your alternantor. Connect your only your alternator to your system. Don't blame me if stuff acts "wierd".

And no one said that voltage poses no danger. There is more than "an element of truth" to that saying. so you know, it's the potential difference with you completing the circuit that is dangerous. you can touch those high voltage lines if you yourself have the same voltage. Aslong as there is no difference, your cool. Try having no potential difference while standing on the ground. boom! toast! Huge potential difference. Ever seen a bird on a power line? they are experiencing thousands of volts. but no potential diff means no cooked bird for supper. The human body can handle thousands of volts but only about .5 amps. increase the amperage enough for even a small voltage and your gone leaving nothing but smoking shoes. Do you know the difference between volts and amps?

You've just managed to incorrectly oversimplify and incorrectly generalize a simple system.
Jeremy H
 

New member
Username: Krazy_karl

Kansas City, USA

Post Number: 10
Registered: Oct-04
Of course I read it all. I wasn't being sarcastic. This is fantastic. I hope that you guys disagree for another couple weeks on this deal.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2302
Registered: May-04
"Maybe you should try this. Disconnect your alternator. Turn on you system and bump it as loud as you like. Turn on your car. turn up the system. having any trouble? if so, it's due to your weak electrical system... Add a cap. Still no trouble just a little more output when needed (No more laging amplifier)...... now Reconnect the alternator. Now that your battery is in need of charging you can get serious use from your alternantor. Connect your only your alternator to your system. Don't blame me if stuff acts "wierd"."

You neglected my explaining of this above. The battery aids to regulate the alternator's output, and helps during those periods of time that the alternator is incapable of supplying the required power, such as at idle or when the regulator is kicked in, but during normal driving periods the alternator should always be the sole source of current. Both can supply the system, and rely on each other. But a system running off just the alternator would last a lot longer, because the alternator could supply current forever (at least until it breaks down). The battery is simply the reference point, that's why people commonly think that power comes from the battery, BUT since the alternator is the point of least resistance, current really comes from the alternator. The reason you don't run off of just the alternator is the nasty voltage spikes that would occur. Current is capable of coming from both, but it's really stupid to say "Disconnect this, and the system will still work" because you could say that about both the alternator and battery, because they share a parallel connection. When the car is running, the alternator is the source of energy, PERIOD. For proof, all you have to do is measure the voltage while the engine is running. It should be approximately 13.5-14.4 volts DC. Then turn the engine off and measure the battery voltage again. Now it'll be around 12-12.5 volts. Whenever the voltage at the battery is up around 14 volts, there is current flowing into the battery. This page will very simply explain to you WHY the alternator is the supply in a charging system. http://www.bcae1.com/charging.htm
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 537
Registered: Sep-04
Whatever, Jeremy.

Here are couple facts you are a bit misinformed about.

1) any large farad cap charged at 18 volts or less ain't gonna kill anybody. 18 volts is NOT enough voltage to provide the necessary .5 amp current through your body due to its high resistance.

2) There's no special protection circuitry in the typical store-bought stiffening cap.

3) although a battery, an alternator, and a stiffening cap all have different operating characteristics/limitations, they all can be viewed as "simple" DC voltage sources in a mobile audio system to simply explain how things work. Whichever "source" has the highest voltage potential will be the device that is powering your system at that moment.

Its that simple and its not my problem if refuse to accept that.

-Fishy

[note] and any links I provided were there for your's and other's benefit, not mine.


 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 538
Registered: Sep-04
[edit] should read "not my problem if you refuse to accept that"
 

Bronze Member
Username: Chevy_for_life

Post Number: 86
Registered: Sep-04
Jermey ur makin yourself look like an @SS just let it go...
 

ZAP
Unregistered guest
your typical car audio cap WILL NOT HURT YOU!!!

i have presonnaly touched the terminals on mine (not on purpose, but i have).

Oh, and the real reason that the birds on the high-lines dont get fried it because their bodies are not grounding! it they touched 2 lines at once, then yea you will get a cooked bird. believe me...i have seen birds get cooks, lmmfao! (squirrels too...lol)
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 539
Registered: Sep-04
lol, squirrel climbing on transformer make BIG bang, but make my TV go off.

:-(

-Fishy :P
 

audiobahn user
Unregistered guest
lol
 

Silver Member
Username: Johnnylemoine

LaPlace, Louisiana United States

Post Number: 169
Registered: Aug-04
HAHAHA!
I dont like jeremy, he acts like an @$$ to everybody, like a know-it-all.
Jonathan and Fishy are keepin it real.
 

Bronze Member
Username: Chevy_for_life

Post Number: 89
Registered: Sep-04
yep i agree Johnny.. Fishy dose good job too..
 

Silver Member
Username: Johnnylemoine

LaPlace, Louisiana United States

Post Number: 176
Registered: Aug-04
hell yeah.
 

Jeremyh01
Unregistered guest
I appreciate your comments BADAZZBOWTIE.
But it is important to understand guys that what is right is not always popular and what is popular is not always right. Ignorance is bliss i guess though.
Fishy, volts don't kill, amps kill. Why do you think those 18 volts teamed with your resistance don't kill you. try 18 volts with a higher amperage. you'll learn something real quick! use those research(homework) skills to find some correct information about the difference in voltage and amperage.
and ZAP, there is no potetntial difference or completion of a circuit through "grounding" or "touching " so the bird lives. If the bird completed a circuit inwhich the sides he connected had a potential difference(laymens terms--> touched something else not at the same voltage---ie pole, other wire, the ground), the bird would be toast.
Johnny, what you said is fine. You don't have to like me. I actually prefer that you don't. Why would i want the support of an ignorant half wit. Don't get angry, you asked for that. Can't take it? Fine. Don't cry about it.
Afterall, Knowledge is power. If you have none but only half truths, you probably shouldn't talk. That was not meant to be condescending or demeaning, just honest.
I don't mean to come off like a know it all either. But i will not dumb myself down so that you can keep up or so that you feel you know what is going on. If you have something to clarify, put in your two cents. otherwise, keep your child like comments to your self.
I have only attempted to point you in the right direction. in the beginning of this thread, which i happened to stumble upon, i found some grossly distorted ideas. I attempted to clarify. Peoples ignorance won out. I retried and found some obstinent people who enjoy the wrong information.
More power to you. Be leary though, Ignorance will only carry you so far.
So krazy Karl, i don't think it will go that far. Fish has proven his obstinance or hard headedness, "Its that simple and its not my problem if you refuse to accept that. -Fishy"
How does that saying go again Karl, you can lead an @ss to water but you can't make him drink! ..... or was it horse?

You're right about one thing johnny, "Hell yea."
Jeremy H
 

Bronze Member
Username: Chevy_for_life

Post Number: 93
Registered: Sep-04
Jeremy if u dont care what we think of you and all this Sh!t that ur goin on about.. then why do u keep reposting?????? just shut up!!!!
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 553
Registered: Sep-04
lol, Jeremy, whatever you say guy. I'm done arguin, but I'll leave you this to dwell on.

V = IR

Its the Law

-Fishy
 

Anonymous
 
V=IR...... precisely.

What are you going to do to raise said current Jeremy, lick the damn thing? Juggle it with wet hands? Incidently, it takes much much less than half an amp to kill, it's more like 10mA, for a period of 1 second or more, through the heart. That's why you use the one hand rule around high voltage. Generally body resistance with dry skin is ~1Meg ohm (changes from person to person somewhat). So it would take "around" 10 000Volts to really get you smoking, and at 18volts, you're being shocked with about 18uA, can't feel it can ya. This is all highly speculative mind you, there's no hard and fast rule as to what kills, so it's best to always play safe.

What someone came close to, but failed to nail down:

Cables/wires have inductance, and inductance resists changing currents, this is the true transient killer, not the electro chemical/internal resistance of the battery! BTW, Try putting a screw driver across your battery terminals and tell me how long it takes before you hear a fizzle if you need proof, I think you'll find it's not slow at all.

We are working faaaaaar below the speed of light when it comes to audio signals.

So the reason for stiffening caps is but one, to cancel the inductance of the looooong power cable, thereby providing a localized source, the fact that it acts to help smooth the voltage even more, is just a bonus, and not the real goal of having them.



 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2349
Registered: May-04
Actually, amps really are what kill you. Just the way it's put, an ampere is 1 coulamb (6.24×10^18 electrons) that passes by a certain point in 1 second. Voltage is a measurement of potential difference (deficiency of electrons on one side, stockpile on the other) and since opposites attract, electrons will move to the atoms that have a deficiency. It is the actual electrons moving through the load (in this case the human body) that kill you. BUT, like the equation states, you can't have one w/o the other, volts and amps are eternally bound. If you raise voltage, amperage will raise as well given the same resistance. Higher voltage means higher amperage, and thus higher voltage has more potential to kill. People can be killed with something as small as a 9V battery, although it is rare. Look here: http://www.darwinawards.com/darwin/darwin1999-50.html
1 ma is enough to give a tingling sensation. OSHA lists how much electricity it takes to be fatal. http://www.osha.gov/SLTC/etools/construction/electrical_incidents/eleccurrent.ht ml
The resistance of the skin is around 100,000 ohms when dry. Most people don't realize that the skin usually isn't totally dry, though, due to perspiration (even very minor, you may not even notice it). Electric shock isn't something to take your chances with. There have been people killed with 9V batteries, and people who have survived lightning strikes, and it all depends on how they ground and their resistance basically.
 

Anonymous
 
Hi Jonathan,

You've complicate the issue, why? it's easiest summed up as ohms law and left at that.

I never at all implied amps aren't what kill, I did however imply an 18V cap under normal circumstances with normal precautions won't.That is, you're not going to lick it, sit on it, or play around with it with soaking wet hands.

When I say dry skin resistance, I simply mean you didn't soak your hands in a pail of water, of course there's oil /sweat.Now 100K ohms seems rather low, I've never seen dry skin (sweat included) measure so low. If I jab probes into my hand hard enough (as opposed to taking the information off of a website)to leave a serious dent but not draw blood, I'll get around 500K, if I jab them into my arm, I'll get absolutely no reading, even on the 2Meg scale. If I wet my skin, it's still ~350K. I have seen many people test themselves and not one has attained so low as 100K. So I'm more inclined to agree with the ~500k stated in your darwin award link, but it can also be ~2Meg or ~1Meg.. or ~1k(there's always the expection to the rule).

This does vary widely from person to person, part of the reason why it's such a speculative subject. How much Iron do you have in your diet, drink much coffee/beer.. etc.

You'll note that in the case of the darwin award, meter probes were intentionally pushed "through" the skin of the thumbs, which of course gives a low resistance path directly through the heart. This is not normal use with normal precautions.

Now I find the page you've linked to is OK, yet flawed in that it tries to nail down all the ratings in typical government efficiency. So here's another for people to look at http://www.ibiblio.org/obp/electricCircuits/DC/DC_3.html
What I like about this page, is while it may not all be entirely believable, it does show you there are no cold hard facts regarding any of this.

Though I stand by, under normal circumstances with normal precautions, an 18V cap is far from lethal:

1.Worst possible screw up, the cap is fully charged and you touch one lead with each hand (dry skin, I'm assuming no one is dumb enough to use em with wet hands), the shock you get won't even be felt.

2. Normal precautions: Read this part real carefully folks, Make sure the cap is fully discharged before you play with it!! Sooner or later some fool is going to "weld" one to his gas tank.. and get stiffening caps outlawed.
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 569
Registered: Sep-04
Well dammititalltohell! :P

Now I gotta remove those spring loaded, needle sharp test leads from my power cap.

I was gonna put those "tazer" guys outa business, but looks like I might kill someone. Better test it on the cat first.

:-)

-Fishy
 

Gold Member
Username: Glasswolf

NorthWest, Michigan USA

Post Number: 4762
Registered: Dec-03
"your typical car audio cap WILL NOT HURT YOU!!!"
I disagree with this statement.
touching the terminals won't generally cause the cap to discharge, no.
However, if you charge the cap, wire it backwards, or in some other way misuse the capacitor, it can produce a very concussive discharge.
I can blow the windows out of a car with an average 20V 1Fd electrolytic used for audio systems, and cause fairly severe burns if it's in somebody's hands.

They are dangerous.. you just need to handle them safely and properly.

I'll leave it at that, since I feel any thread that reaches this many posts needs to be disregarded and a new thread opened with the actual topic noted.
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 572
Registered: Sep-04
I dunno this may seem a very long, pointless thread, but if you take the time to read it there's some pretty good info therein.

Its nothin like that "Theater Research" thread over in Speakers.

I'd hate to see this one go..... yet.

-Fishy

[note] How can reverse polarity on an electrolytic cap lead to combustion. I understand how over-voltage can and that reverse polarity can break down the dielectric. Does loss of dielectric material simply reduce the amount of voltage the cap can handle?
 

Anonymous
 
Glasswolf, sounds like you had a few bad experiences and have since learned to treat them with some respect. That's good.

You know, even your shoes will kill you if you use them improperly. (try swallowing one)

Fishy,

You pretty well have got it figured out:
The ensuing breakdown of the dielectric film basically leads to an internal dead short, and so high current flows, which boils the electrolyte, creating high pressure in a sealed container, at which point whatever pressure relief mechanism is built in hopefully kicks in before it turns into a real grenade, and yes, the "pressure relief" can mean the top explodes, with boiling electrolyte spewing all over.

I'd imagine in this case with a car battery attached it would go off in one hell of a hurry as it could have ~1000 amps flowing through it to get it to boil, you wouldn't get the chance to question where that hissing sound is comming from, a very good reason for hooking up the battery last, when your face is well away from it.
 

Gold Member
Username: Glasswolf

NorthWest, Michigan USA

Post Number: 4770
Registered: Dec-03
I haven't misused a capacitor.
I'm an E.E. I know how they work.

I'm sure this therad is useful. My point was just that it doesn't need to be a long evolving thread that changes topics 12 times. Start a new topic and new thread when it's appropriate so I don't need to go refill my drink waiting for teh thread to load.. lol
 

Silver Member
Username: Fishy

Tamarac, FL USA

Post Number: 578
Registered: Sep-04
Oh. I forgot about all the bandwidth challenged out there.

Guess I'm spoilt.

:-)

-Fishy
 

classDchris
Unregistered guest
Hi

Sorry for making that assumption GlassWolf, it was wrong of me. Just the way you said it.. sounded like you had first hand familiarity with it.

Being an E.E doesn't mean much to me, I know what it takes to get through school.. I'll trust that you are one of the few intelligent ones though :-)

Even, mishaps happen to the best of us at times. Now I'll go post some junk in your new thread to give it a good boost.
 

Gold Member
Username: Glasswolf

NorthWest, Michigan USA

Post Number: 4817
Registered: Dec-03
yeah no broadband out here yet *wistful sigh* it blows.

no offense taken, and I know what ya mean about a degree not meaning much. I've met plenty of "paper" network engineers and such as well.. lol
I do have first hand experience, but mostly from being an installer and seeing the aftereffects of people misusing stuff and coming to me to fix it.. lol

anyway it's all good.
hey at least this isn't like that 330-post thread in subwoofers I think it was..
man I won't even open that one.. it scares me. haha
 

ROFL
Unregistered guest
was that 330 post thread the one about BOSS?

lol
 

Bronze Member
Username: Krazy_karl

Kansas City, USA

Post Number: 13
Registered: Oct-04
I just want to know why I got dragged into Jeremyh01's last rant. What the hell did I do?

And Glass, we "paper" network engineers take exception to actually being called that. I personally prefer the term "Government Contractor".
 

Gold Member
Username: Glasswolf

NorthWest, Michigan USA

Post Number: 4851
Registered: Dec-03
no, I remember now, I think it's in security on "wiring diagrams for alarm systems."

what people don't realize is, those codes are guarded like fort knox. companies don't give out color codes for alarm brains to prevent thieves from knowing which wires to cut.
They can ask till they turn blue but they aren't getting the color diagrams for alarms.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 2372
Registered: May-04
The Theater research thread will catch up sooner or later, I'd hope these people will have learned not to buy home speakers out of a white van, and with a 90+% discount from their supposed "retail value". You can get $3200 home cabinets for 100-200 bucks, this doesn't sound shady now does it? Even people that steal speakers that expensive would sell them for more than that.
 

Jeremyh01
Unregistered guest
My last rant! Heck no! I'm back for more..... just joking guys!... relax. I dealt with the ill informed and the immature comments as they came. We did get a bit off topic at times. but hey, things happen. Your right though Glasswolf, This is one long thread that i don't care to read. Where did you get your degree? I got mine at UT.
see you all later. And relax everyone. We can have civilized conversations without losing our cool.
Jeremyh01
 

Gold Member
Username: Glasswolf

NorthWest, Michigan USA

Post Number: 4899
Registered: Dec-03
VPI (Va tech)
EE and English
 

jeremyh01
Unregistered guest
Physics and education. I was an EE major but changed my last year when i saw what it entailed. (My sister is a civil Engineer). I can't handle an office all the time. As a teacher, i get weekends, summers and holidays off with pay(not the greatest i might add)year round.
 

davidryder
Unregistered guest
hey just had to add that your battery is always the source of power for your car. motor running or not. starting the engine doesn't rewire the electrical system, everything still comes from the battery, and the alternator provides a charge for it while the car is running. if the alternator fails when the car is running, the battery will still be powering everything, just discharging very rapidly.
 

davidryder
Unregistered guest
do you guys know what parallel means? battery, alternator, and the loads are all in parallel meaning the circuit can be complete without either a) the alternator or b) the battery. just needs one. all the battery is doing when the engine is running is maintaining a charge. but if the car's electrical load is constantly causing the output voltage to drop below 12v, it will damage the alternator and battery. to stop the output voltage from dropping is upgrading the alternator
 

Gold Member
Username: Glasswolf

NorthWest, Michigan USA

Post Number: 5193
Registered: Dec-03
I think we've all said that about two billion times now.
the point is upgrading a battery isn't the solution to lights dimming when the engine is running.
If the alternator can't supply the required amount of current, the voltage rails sag, the battery doesn't charge because the voltage from the alternator won't be greater than the voltage of the battery, and you'll not only end up damaging the alternator but the battery as well, and the speakers when the amplifiers enter clipping.

What was your point in posting? Particularly to a thread we've esssentially deemed dead.

As long as the car is running above idle, the voltage supplied by the alternator is greater than that of the battery. The battery will be in a charging state. The alternator is supplying the power to the car for all intents and purposes. Yes if the alternator fails the battery will supply power as well, but not for very long and the voltage rails still sag, and still cause damage. IN THIS CONTEXT (car audio), the alternator needs to be upgraded if voltage rails sag while driving the car.
 

Laura
Unregistered guest
I hope someone can help me. I havent a clue about cars! How do you install the power cap? The instructions I got dont make sense to me!

Please help.
 

Bronze Member
Username: Carguy

Post Number: 92
Registered: Nov-04
Hey Laura there is a post already on installing that. Try under another main topic.
 

Bronze Member
Username: Carguy

Post Number: 93
Registered: Nov-04
Here's the link Laura.
https://www.ecoustics.com/electronics/forum/car-audio/107876.html
« Previous Thread | Next Thread »

Facebook

Shop Related Deals

Directory

Main Forums

Today's Posts

Forum Help

Follow Us