When should you consider getting a capacitor for your car audio
system. Would 800watts be helped out by a capacitor or would it just
be a waste of money.

people always get caps b/c there lights are dimming. i dont know why
they waist there money on them a 2nd battery will work better. upgrade
the car battery to the biggest cca that you can fit then upgrade all
wires to the alt and then upgrade alt .caps are a temp fix do it right
the frist time and save the money from the cap and get the alt
--
trex160s
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"trex160s" wrote in message
s.com...
people always get caps b/c there lights are dimming. i dont know why they
waist there money on them a 2nd battery will work better. upgrade the car
battery to the biggest cca that you can fit then upgrade all wires to the
alt and then upgrade alt .caps are a temp fix do it right the frist time
and save the money from the cap and get the alt

you do realize that if you don't upgrade the alt first you can make the
situation worse. the proper setup should be, wire, alt, batt, and cap, in
that order.

s.com...
people always get caps b/c there lights are dimming. i dont know why they
waist there money on them a 2nd battery will work better. upgrade the car
battery to the biggest cca that you can fit


Not even close. All a bigger battery does is provide more engine off
listening time. When the car is running the battery is nothing more than a
load, just like a light or your defroster.


then upgrade all wires to the
alt and then upgrade alt .caps are a temp fix do it right the frist time
and save the money from the cap and get the alt

I agree about upgrading the alternator first, but a cap does a different
job.



you do realize that if you don't upgrade the alt first you can make the
situation worse.

Care to explain how? Cuz that's total BS.



the proper setup should be, wire, alt, batt, and cap, in
that order.

Really? I've never change a battery in any of my cars, including my
competition cars.


Paul Vina

I'll second the opinion that additional batteries and/or
larger batteries are unnecessary. Batteries are for starting the car
or running the system with the engine off - that's all.

Furthermore, alternators only need to be able to keep up with
the *average* current demand, not the *peak* demand. As long as you
can drive around all day listening to music at your normal volume and
not drain your battery, your alternator is sufficient. Now, for those
large transient peaks that your alternator *can't* handle, that's
where capacitors come in. Caps have an extremely low internal
resistance, so they can provide huge bursts of current for short
periods of time with almost no voltage drop. As long as your
alternator can handle your car's average current requirements, it's
not a "band-aid" or bad engineering to use a capacitor to handle the
transients.

Think of a typical toilet. When flushed, they have to be able
to get rid of about a gallon of water in 10 or 15 seconds (about 4-6
gallons per minute). Now look at the water supply line coming in from
the wall. Odds are, it's so small that it could never flow the
required 4-6 gallons per minute to handle a flush. How do they get
around this problem? The toilet tank that sits on top of the bowl
holds a gallon or so of water in reserve. This tank is refilled from
the small-diameter supply line in-between flushes. If you didn't use
a tank, the only other option would be to use a much bigger supply
line that could handle the peak flow rate required for a flush.

In a car, the supply line would be the alternator, the toilet
tank would be the capacitor, and flushing the toilet would be an
example of a peak transient. As long as your tank is big enough to
handle the transient peaks, you can get away with a smaller supply
line.


Scott Gardner



On Fri, 17 Oct 2003 22:06:22 -0400, "Tha Ghee"
wrote:


"trex160s" wrote in message
ws.com...
people always get caps b/c there lights are dimming. i dont know why they
waist there money on them a 2nd battery will work better. upgrade the car
battery to the biggest cca that you can fit then upgrade all wires to the
alt and then upgrade alt .caps are a temp fix do it right the frist time
and save the money from the cap and get the alt

you do realize that if you don't upgrade the alt first you can make the
situation worse. the proper setup should be, wire, alt, batt, and cap, in
that order.

I'll second the opinion that additional batteries and/or
larger batteries are unnecessary. Batteries are for starting the car
or running the system with the engine off - that's all.

Batteries do in fact supply current to the audio system. Try running a
system with the car on and the battery disconnected. Oftentimes the
amplifiers will shut off due to voltage below threshold. In addition, a
poor battery will draw excess current from the alternator when charging.
This also has a detrimental effect.

Furthermore, alternators only need to be able to keep up with
the *average* current demand, not the *peak* demand. As long as you
can drive around all day listening to music at your normal volume and
not drain your battery, your alternator is sufficient. Now, for those
large transient peaks that your alternator *can't* handle, that's
where capacitors come in. Caps have an extremely low internal
resistance, so they can provide huge bursts of current for short
periods of time with almost no voltage drop.

The voltage drop is proportional to the time. That means that there's
ALWAYS a voltage drop as the capacitor discharges, and it can become
quite substantial for "typical" (whatever that is) transients. This can
all be verified with mathematics also.

As long as your
alternator can handle your car's average current requirements, it's
not a "band-aid" or bad engineering to use a capacitor to handle the
transients.

The engineers already put them inside the amp. Are you suggesting their
engineering is inadequate?

Batteries do in fact supply current to the audio system. Try running a
system with the car on and the battery disconnected.

That's a sure way of damaging your alternator.

Oftentimes the
amplifiers will shut off due to voltage below threshold.

Yes they will, alternators do not respond fast enough to power peaks, causing
voltage drops triggering under-voltage protecting in the amplifier, shutting
it off . That's where a capacitor comes in to play.

In addition, a
poor battery will draw excess current from the alternator when charging.
This also has a detrimental effect.

What is a poor battery, a faulty one ?
.

The voltage drop is proportional to the time. That means that there's
ALWAYS a voltage drop as the capacitor discharges, and it can become
quite substantial for "typical" (whatever that is) transients. This can
all be verified with mathematics also.

True, most this voltage drop occurs between the battery and capacitor and not
as much so between the capacitor and amplifier.


The engineers already put them inside the amp. Are you suggesting their
engineering is inadequate?

Yes, Mid-grade amplifiers such as some Kenwood, Alpine amplifiers, use paper
electrolytic capacitors that are way to small for their application. Not that
long ago, I have bench tested a Profile 200 watt rms mono block amplifier
after replacing a few burnt out output mosfets. At 14 volts with a current
draw of about 18amps at peak the power led stated dimming. At that point i
have ripped the amplifier apart again and upgraded the power hexfets to lager
ones, I also doubled the size of the power capacitors and changed them from
paper film to aluminum film capacitors, and that totally eliminated the power
led dimming problem that this amplifier had at high volumes.

On Sun, 30 Nov 2003 03:00:49 GMT, Mark Zarella
wrote:

I'll second the opinion that additional batteries and/or
larger batteries are unnecessary. Batteries are for starting the car
or running the system with the engine off - that's all.

Batteries do in fact supply current to the audio system. Try running a
system with the car on and the battery disconnected. Oftentimes the
amplifiers will shut off due to voltage below threshold. In addition, a
poor battery will draw excess current from the alternator when charging.
This also has a detrimental effect.

I agree that the battery will provide current when the
alternator cannot keep up with the load. Unfortuneately, the battery
is a poor candidate for this job, since it has a relatively high
internal resistance. This resistance, combined with a high current
drain, will cause a significant voltage drop. This is why it's
acceptable for even a "good" battery to drop from 12V all the way down
to 9.6V while cranking over the engine.
Capacitors have a MUCH small internal resistance, so they can
provide a larger surge of current without a corresponding large
voltage drop.

Furthermore, alternators only need to be able to keep up with
the *average* current demand, not the *peak* demand. As long as you
can drive around all day listening to music at your normal volume and
not drain your battery, your alternator is sufficient. Now, for those
large transient peaks that your alternator *can't* handle, that's
where capacitors come in. Caps have an extremely low internal
resistance, so they can provide huge bursts of current for short
periods of time with almost no voltage drop.


The voltage drop is proportional to the time. That means that there's
ALWAYS a voltage drop as the capacitor discharges, and it can become
quite substantial for "typical" (whatever that is) transients. This can
all be verified with mathematics also.

Again, you're absolutely right. There is a voltage drop across the
capacitor's terminals as a load is applied, but we can vary how
quickly the voltage drops by varying the capacitance. Depending on
our needs for a particular installation, we can make the discharge
time constant equal to whatever we want by using smaller or larger
capacitors.

As long as your
alternator can handle your car's average current requirements, it's
not a "band-aid" or bad engineering to use a capacitor to handle the
transients.

The engineers already put them inside the amp. Are you suggesting their
engineering is inadequate?

I think the engineers do the best they can within the
constraints of packaging size, cost, and the fact that they can't
predict how exactly the amp will be used. They don't know how much
capacity your car's alternator has, or what other loads are sharing
that capacity.
My guidance is that unless you know for certain that
your stock alternator isn't up to the task (like trying to put 3000
watts of amplification in a stock Civic), give it a try without
upgrading the alternator or adding a capacitor. If you can drive
around all day playing music at your normal levels without discharging
the battery, then your alternator is obviously capable of handling the
*average* load you're putting on it. At this point, either
everything's good, or you're getting some dimming of lights during
large transients. Now, I would try a capacitor. Start off with the 1
Farad/kW estimate and go from there. If that still doesn't solve the
problem, you have to find out which is cheaper - more capacitance, or
a higher-capacity alternator. Some applications are cheap - you can
get 150A alternators for Hondas for less than $250. For older or more
offbeat cars, the choices are slimmer.
I'm not saying that every installation needs a capacitor, and
I'll admit that beyond a certain point, it becomes more cost-effective
to put in a higher-capacity alternator. I'm just responding to the
people that make blanket statements like "capacitors suck", or blindly
follow rules-of-thumb like "one Farad per 1,000 watts amplifier
power".

Scott Gardner

Here is my experience: I had 500W Amp. + JLW6, when I cranked up my music
without the cap., and whenever it came across strong bass, the amp. shut
down by itself (underpowered) and then turned back on after 5 sec. so I
installed a 1 Farad cap. and solved the problem!

Side notes: I didn't see a lot light dimming, only slightly.. so light
dimming wasn't a good indicator in my case.


"Nathan" wrote in message
om...
When should you consider getting a capacitor for your car audio
system. Would 800watts be helped out by a capacitor or would it just
be a waste of money.

i had a 1 farad cap on my rf 800a2 and it didnt do didly squat


--
capone
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caps are junk!


--
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Only if you're trying to get it to do something it wasn't meant to do. Caps
aren't meant to keep headlight from dimming, they're to provide voltage
quickly when the alternator can't keep up, but only for very quick bursts.


Paul Vina



"capone" wrote in message
...

caps are junk!


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I eould highly reccomend againtst a cap. yeah some of them look cool and
unless you are planning on a show setup there aint no point to having one.
In mine and most others opinion a second battery with an isolator and a
higher amp capable alternator (or two or more even) will give you much
better results. Even if you only change your stock battery to something like
an Optima RedTop you might notice some performance gain.

EFFENDI

"Nathan" wrote in message
om...
When should you consider getting a capacitor for your car audio
system. Would 800watts be helped out by a capacitor or would it just
be a waste of money.

FYI, Adding a "stiffening" capacitor to a fully regulated amplifier won't
even help at all. You can tell if your amplifier has a fully regulated
supply by checking to see if it has a secondary storage device in the amps
PS. Usually, it will be another ferrite core wound with wire just like the
PS transformer. I wouldn't recommend opening your amp up just to check, but
I would tell you to contact your amp manufacture's tech support and ask
them.

Adding a second, isolated battery/alternator UG is always good. Keeps you
from stranding you somewhere with a dead battery ( if done proper ) as well
as adding capacity. Just be sure and use a sealed battery if you plan on
placing it in the trunk. It is against the law in many states to put a
vented battery in a "sealed" or passenger area. Vented batteries give off
poisonous/corrosive/explosive vapors when charged.

Taffer Garrett

"Nathan" wrote in message
om...
When should you consider getting a capacitor for your car audio
system. Would 800watts be helped out by a capacitor or would it just
be a waste of money.

I have no first hand experience with Caps in my system. I never felt the
need for one. If my amps were overloading the electrical system in any way
I wouldn't fix it with a cap. My choice would be a high output alternator.

This is my understanding....
Its a product that many times does nothing to improve SQ or SPL. IMHO its
used as a band aid, quick fix to try and cover up an overloaded alternator.
Your SPL scores will not improve, if anything your SPL will decrease, as the
cap is placing an additional load on the alternator. If your headlights are
dimming, adding a cap will provide extra current for transient peaks, but at
the same time youre adding a load to the alternator and taking precious
power away from your amps.

Again, I dont have first hand experience with caps in my system... unless
someone can convince me they are worth the $$$ :~) If I did need an
electrical system upgrade an alternator would be my choice.... fix the root
cause.

Garrett

"Nathan" wrote in message
om...
When should you consider getting a capacitor for your car audio
system. Would 800watts be helped out by a capacitor or would it just
be a waste of money.

Just put .05f caps on your headlights if it bothers you so much
"sanitarium" wrote in message
news:1065206183.423449@sj-nntpcache-5...
I have no first hand experience with Caps in my system. I never felt the
need for one. If my amps were overloading the electrical system in any
way
I wouldn't fix it with a cap. My choice would be a high output
alternator.

This is my understanding....
Its a product that many times does nothing to improve SQ or SPL. IMHO its
used as a band aid, quick fix to try and cover up an overloaded
alternator.
Your SPL scores will not improve, if anything your SPL will decrease, as
the
cap is placing an additional load on the alternator. If your headlights
are
dimming, adding a cap will provide extra current for transient peaks, but
at
the same time youre adding a load to the alternator and taking precious
power away from your amps.

Again, I dont have first hand experience with caps in my system... unless
someone can convince me they are worth the $$$ :~) If I did need an
electrical system upgrade an alternator would be my choice.... fix the
root
cause.

Garrett

"Nathan" wrote in message
om...
When should you consider getting a capacitor for your car audio
system. Would 800watts be helped out by a capacitor or would it just
be a waste of money.