In article ,
"Kim Inglar" wrote:

Why do you use a capacitor? what is it good for? And do you realy have nead
for it if you have large batteries?


They attempt to hold the voltage steady. Unfortunately they have
minimal value for car audio amps. If the voltage is drooping from thin
wire, the better solution is bigger wire. If the voltage is drooping at
the battery, you're drawing too much current for a capacitor to be
useful. (You probably need a more efficient system if you're loading
down the battery!)

A capacitor doesn't do anything to help the alternator. They don't
store nearly enough power for that.

One farad is the capacitance where 1 amp causes a 1 volt/second change.
A 1/60 second surge at 60A would drain a 1F cap 1V or a 2F cap 0.5V.

In article m, "KaeZoo" wrote:

"GregS" wrote in message
...
In article m, "KaeZoo"
wrote:

"Scott M" wrote in message
...
KaeZoo wrote:


My point was that a capacitor's purpose is NOT to assist the alternator.

If the car is running a capacitor will supply or "assist" the alternator,
which
also includes, assisting fuses, wiring , connections.

The cap tries to maintain voltage, period.

greg

The cap isn't creating power. Only the alternator can do that, by
converting mechanical power to electrical power.

The alternator generates the voltage that the cap tries to maintain. If the
cap discharges to maintain voltage in the circuit, the alternator must work
to recharge it.

The only benefit of the capacitor is that it can react to changes in voltage
more quickly than the alternator can.

It can act with more authority, but not speed.
The electricity does not change speeds. It will come out of one as fast as the other.
As I mentioned before, the cap improves upon voltage depression from lossy
resistive lines, and it smooths out transitions which the alternator can not supply,
due to given RPM, and output capability at that RPM. The alternator is also supplying other
currents, like air conditioning clutches, lights, etc. The cap is at the amp, so it has a slight
buffer of resistance between everything else.

Basically the capacitor "assists" the alternator in the same way that my
credit card "assists" my cash flow. I may be able to pay for lunch a little
faster, but I'm not working any fewer hours because of it.

On Wed, 16 Jul 2003 at 20:14 GMT, GregS wrote:
In article m,
"KaeZoo" wrote:
The cap isn't creating power. Only the alternator can do that, by
converting mechanical power to electrical power.

The alternator generates the voltage that the cap tries to
maintain. If the cap discharges to maintain voltage in the
circuit, the alternator must work to recharge it.

The only benefit of the capacitor is that it can react to changes
in voltage more quickly than the alternator can.

It can act with more authority, but not speed. The electricity
does not change speeds. It will come out of one as fast as the
other. As I mentioned before, the cap improves upon voltage
depression from lossy resistive lines, and it smooths out
transitions which the alternator can not supply, due to given RPM,
and output capability at that RPM. The alternator is also
supplying other currents, like air conditioning clutches, lights,
etc. The cap is at the amp, so it has a slight buffer of
resistance between everything else.

I think KaeZoo has it right except for the fact that it isn't speed,
but simple cash flow...

It is not that the credit card allows you to have access to money
faster, it allows you a larger buying power then you actually have
at any give point in time. In the end, you do have to pay it back.

Here is another example:

Think of a capacitor as a large bucket of electricity that is filled
from the top by the alternator and is always tilted over just a bit
to feed the amp. Under a normal load the alternator has more then
enough current to keep the bucket filled up. There are times (when
hitting loud and low bass notes), though that the amp will need to
pull significantly more current then the alternator is able to
deliver. For those times, the amp simply pulls the capacitor over
enough to get the all the current it needs for that bass note. Then
the alternator ups what it is putting into the bucket as to still
feed the amp, but to also replenish the capacitor.

Sam

Kim Inglar wrote:

I´m not going to play that mutch with the engine off. It´s going to be used
when I´m driving to work and other locations. But do you think it will be
enough with an alternator that deliveres 70A?

Kim

I used to run a 400 watts system of a 30 amps alt. Of course, the
headlights dimmed like crazy but I never actually drained the battery.
I have now upgraded to a 55 amp alt and Optima yellow top battery which
is more than sufficient...

--
Eric (Dero) Desrochers

Hiroshima 45, Tchernobyl 86, Windows 95

By now the solution seems to be clear:

1) Largest gauge and shortest run mains possible.
2) High capacity battery.
3) High output alternator.
4) Use money budgeted for capacitors for items one through three above,
unless you want to spend it for "show not go."

Best,

Phil Sharkey

On Thu, 17 Jul 2003 at 15:47 GMT, Phil Sharkey wrote:
By now the solution seems to be clear:

1) Largest gauge and shortest run mains possible.
2) High capacity battery.
3) High output alternator.
4) Use money budgeted for capacitors for items one through three above,
unless you want to spend it for "show not go."

That is one solution, all depending on how you value capacitors.
There is also the issue of price. It looks like a 1 farad caps is
less then $100 normally. A high output alternator for my car is
going to cost somewhere around $300 to $400.

Personally I think a cap is a much better investment then a high
output alternator, assuming your alternator has enough umph to drive
the system, normally. Which it is my understanding most alternators
do until the system reachs the 1000+ watts area.

Sam

--
See my links engine for a collection of sites that
might be of interest to you. Your additions will
make this engine more powerful global resource.
http://www.miltonstreet.com/scarleton/links/

Caps provide your system an extra surge of power that the battery or
alternator cannot supply.

Normal Stereos, or minimal systems do not need caps for they do not draw a
lot of power.

To know whether or not you need a Cap or not, throw a bass test CD into your
car, and play the music the way you noramlly would. If your lights in your
car dim, the engine revs like mad and the check battery light comes on in
your car, install a cap.

I have 2 -3 Fadad Caps in my show vehicle. 8,000 watts of RMS Power.
Regardless of what anyone says, the main line fact is that if you need an
instant-power source due to a bass hit or power spike to deal with peak
wattage then get a cap. A Cap. however will not do anything if you are
contantly overpowering your battery or alternator. Getting a bigger battery
might help, but make sure that it is a high powered one, you will probably
need to re-build the battery box in your car, since a stock battery or one
that is the right size for your vehicle will get over-driven and you will
tear though a battery in a matter of months.

K

"Kim Inglar" wrote in message
...
Why do you use a capacitor? what is it good for? And do you realy have
nead
for it if you have large batteries?

--
Det ER størrelsen det kommer ann på. 18" eller mer.

Kim Inglar

The discussion reminds me of a bumper sticker I saw the other day,
"Lotteries are taxes paid by people who can't do math."

Best,

Phil Sharkey

Hello,

I have a massive pair of spotlights which cause the engine to rev lower and
it really puts a load on the battery. So are you also claiming that a
capacitor will also help this. The capacitor will not know it's not an
expensive audio amp, unless you can get "intelligent" ones!

I have never read so much rubbish in my life - the reason they are sold is
to make money out of people that are a bit thick. The type that will buy
blue LED washer jets, induction kits to suck hot air from around the engine,
big exhausts and wheels that could fit onto a tractor.

So long as you THINK it does something then good for you. If that's what
you want to believe in!

"Kevin Glass" wrote in message
ble.rogers.com...
Caps provide your system an extra surge of power that the battery or
alternator cannot supply.

Normal Stereos, or minimal systems do not need caps for they do not draw a
lot of power.

To know whether or not you need a Cap or not, throw a bass test CD into
your
car, and play the music the way you noramlly would. If your lights in
your
car dim, the engine revs like mad and the check battery light comes on in
your car, install a cap.

I have 2 -3 Fadad Caps in my show vehicle. 8,000 watts of RMS Power.
Regardless of what anyone says, the main line fact is that if you need an
instant-power source due to a bass hit or power spike to deal with peak
wattage then get a cap. A Cap. however will not do anything if you are
contantly overpowering your battery or alternator. Getting a bigger
battery
might help, but make sure that it is a high powered one, you will probably
need to re-build the battery box in your car, since a stock battery or one
that is the right size for your vehicle will get over-driven and you will
tear though a battery in a matter of months.

K

"Kim Inglar" wrote in message
...
Why do you use a capacitor? what is it good for? And do you realy have
nead
for it if you have large batteries?

--
Det ER størrelsen det kommer ann på. 18" eller mer.

Kim Inglar