I am going to be doing my first nice install in any of my cars in my new (to
me) 99' 528i. I have a Directed 1100d (old style Black and Silver). I am
going to be going with 4 of the Kicker S8L5's in a sealed box. I love the
sound of the current S10L5 I have but want a bit more sometimes. Now I think
I have it measured correctly for Amp/Sub ratio. That Amp should put out
exactly the right amount for those 4 subs in a 1ohmish load.

My question is:

I REALLY don't want to jack up the battery or any of the power devices or OE
cabling in the car, I haven't really cared in the past with my Junker cars
but this one I want to take car of. My question is, with that type of setup.
Should I buy a Optima Yellow top and install that into the car also? Or
would a standard 1 Farad Cap or 2 do the job well enough to cover
everything.

If you need anymore info on the subject please reply and ill try to include
that.


--
Thank you,

~~~
Branden Nelsen

ok.. you need the lanzar 2.4 cap like i got. $99.
theyre going to tell you not to get a cap...theres pros n cons to
it..its your call.not thiers.
the reason for a cap is to supply you bursts of power faster than a
battery can.

now i paid $80 for my cap 8months ago.they went up.
also caps recharge every minute or less,i think alot of people think
they recharge after theyre totally dead.causing you battery problems.

1cap..lol why bother...go bigger or not at all.....

Branden,

With that kind of power you would be fine with a good yellow top and
disregard any notions to caps. Also, completely ignore Bob Wald's advice on
anything car-audio related. I'm sorry to involve you in all this, but we as
a newsgroup are in the process of banning together to ignore him in the
hopes he will go away.

Also, any reason why you want four 8s as opposed to a couple of 10s?

Tony


--
2001 Nissan Maxima SE Anniversary Edition
Clarion DRZ9255 Head Unit, Phoenix Gold ZX475ti, ZX450 and Xenon X1200.1
Amplifiers, Dynaudio System 360 Tri-Amped In Front and Focal 130HCs For Rear
Fill, Image Dynamics IDMAX10 D4 v.3 Sub

2001 Chevy S10 ZR2
Pioneer DEH-P9600MP Head Unit, Phoenix Gold Ti500.4 Amp, Focal 165HC
Speakers & Image Dynamics ID8 D4 v.3 Sub

alot of people here are so crushed i dont need thier advice.theyve
turned bitter.....
or jealous.
in case you dont know a yellowtop costs what $159+....a good cap $99....
get a good 850cca battery at least. $99.....
like me....well i got a 750cca... but i was doing a trade back.that all
they had.without a big jump in price.

On Mon, 24 Oct 2005 13:22:26 -0500, "Branden Nelsen"
wrote:

I am going to be doing my first nice install in any of my cars in my new (to
me) 99' 528i. I have a Directed 1100d (old style Black and Silver). I am
going to be going with 4 of the Kicker S8L5's in a sealed box. I love the
sound of the current S10L5 I have but want a bit more sometimes. Now I think
I have it measured correctly for Amp/Sub ratio. That Amp should put out
exactly the right amount for those 4 subs in a 1ohmish load.

My question is:

I REALLY don't want to jack up the battery or any of the power devices or OE
cabling in the car, I haven't really cared in the past with my Junker cars
but this one I want to take car of. My question is, with that type of setup.
Should I buy a Optima Yellow top and install that into the car also? Or
would a standard 1 Farad Cap or 2 do the job well enough to cover
everything.

If you need anymore info on the subject please reply and ill try to include
that.

If your alternator won't provide enough current to supply your car's
electrical system and your stereo needs, with a little left over to
keep the battery topped off, then no battery or capacitor will help
you.

That being said, I would replace your battery on general principle if
it's the original battery, and an Optima or Stinger is as good a
choice as any.

A 1999 BMW will probably have a pretty stout alternator as standard
equipment, so I'd install the stereo and see if you have any problems
with you battery discharging, lights flickering/dimming, etcetera, and
then go from there.

Unless you're cranking the stereo at full blast all the time, the
*average* current requirements for your stereo will be surprisingly
low, even for a "big" stereo.


--
Scott Gardner

"Invalid thought detected. Close all mental processes and restart body."

The reasoning I am wanting the Four 8's instead of Two 10's is that with the
L5 series by kicker (Square subs) the 8" equals the surface area of a
standard 10" round sub. In this setup I would be running the equivalent
surface area of Four 10"s in a sealed box. Also with 8" L5 they only require
a .33ft^3 box per sub. In my 528i ill have those 4 in a total 2ft^3 box with
each having their own .5ft^3 box inside the box as a "whole". This will Fit
nicely in the front part of the trunk and still leave me access to a useable
spare tire while having a nice professional looking install.


"Tony F" wrote in message
...
Branden,

With that kind of power you would be fine with a good yellow top and
disregard any notions to caps. Also, completely ignore Bob Wald's advice
on anything car-audio related. I'm sorry to involve you in all this, but
we as a newsgroup are in the process of banning together to ignore him in
the hopes he will go away.

Also, any reason why you want four 8s as opposed to a couple of 10s?

Tony


--
2001 Nissan Maxima SE Anniversary Edition
Clarion DRZ9255 Head Unit, Phoenix Gold ZX475ti, ZX450 and Xenon X1200.1
Amplifiers, Dynaudio System 360 Tri-Amped In Front and Focal 130HCs For
Rear Fill, Image Dynamics IDMAX10 D4 v.3 Sub

2001 Chevy S10 ZR2
Pioneer DEH-P9600MP Head Unit, Phoenix Gold Ti500.4 Amp, Focal 165HC
Speakers & Image Dynamics ID8 D4 v.3 Sub

As far as the Cap being $99 and the Yellowtop being $159+, I dont have to
worry about that i can get a Yellowtop for abour $120. so that price doesnt
matter.

-Branden

"bob wald" wrote in message
...
alot of people here are so crushed i dont need thier advice.theyve
turned bitter.....
or jealous.
in case you dont know a yellowtop costs what $159+....a good cap $99....
get a good 850cca battery at least. $99.....
like me....well i got a 750cca... but i was doing a trade back.that all
they had.without a big jump in price.

Thanks for the link ill look it over!

-Branden


"I. Care" wrote in message
.net...
In article , says...
I am going to be doing my first nice install in any of my cars in my new
(to
me) 99' 528i. I have a Directed 1100d (old style Black and Silver). I am
going to be going with 4 of the Kicker S8L5's in a sealed box. I love the
sound of the current S10L5 I have but want a bit more sometimes. Now I
think
I have it measured correctly for Amp/Sub ratio. That Amp should put out
exactly the right amount for those 4 subs in a 1ohmish load.

My question is:

I REALLY don't want to jack up the battery or any of the power devices or
OE
cabling in the car, I haven't really cared in the past with my Junker
cars
but this one I want to take car of. My question is, with that type of
setup.
Should I buy a Optima Yellow top and install that into the car also? Or
would a standard 1 Farad Cap or 2 do the job well enough to cover
everything.

If you need anymore info on the subject please reply and ill try to
include
that.



Look here first to see how a cap works and if you need one:

http://www.mobileaudio.com/rac-faq/


--
I. Care
Address fake until the SPAM goes away ;-}

Unfortunately I am not sure what the power output of my Alt is on that car.

As far as replacing the battery with a Optima or Stinger, Unfortunately
where BMW place's the battery in their cars (Trunk) it requires a battery
that resembles a 'stout' Marine battery, so a normal Yellowtop type battery
wont fit in the stock area. There is however a nice place to install a
second battery above the stock one if I go that route.

Main reason I want a second Battery or a cap is that I don't want to over
tax the Alt or standard battery as I have heard either one is pretty costly
to replace.

-Branden



"Scott Gardner" wrote in message
...
On Mon, 24 Oct 2005 13:22:26 -0500, "Branden Nelsen"
wrote:

I am going to be doing my first nice install in any of my cars in my new
(to
me) 99' 528i. I have a Directed 1100d (old style Black and Silver). I am
going to be going with 4 of the Kicker S8L5's in a sealed box. I love the
sound of the current S10L5 I have but want a bit more sometimes. Now I
think
I have it measured correctly for Amp/Sub ratio. That Amp should put out
exactly the right amount for those 4 subs in a 1ohmish load.

My question is:

I REALLY don't want to jack up the battery or any of the power devices or
OE
cabling in the car, I haven't really cared in the past with my Junker cars
but this one I want to take car of. My question is, with that type of
setup.
Should I buy a Optima Yellow top and install that into the car also? Or
would a standard 1 Farad Cap or 2 do the job well enough to cover
everything.

If you need anymore info on the subject please reply and ill try to
include
that.

If your alternator won't provide enough current to supply your car's
electrical system and your stereo needs, with a little left over to
keep the battery topped off, then no battery or capacitor will help
you.

That being said, I would replace your battery on general principle if
it's the original battery, and an Optima or Stinger is as good a
choice as any.

A 1999 BMW will probably have a pretty stout alternator as standard
equipment, so I'd install the stereo and see if you have any problems
with you battery discharging, lights flickering/dimming, etcetera, and
then go from there.

Unless you're cranking the stereo at full blast all the time, the
*average* current requirements for your stereo will be surprisingly
low, even for a "big" stereo.


--
Scott Gardner

"Invalid thought detected. Close all mental processes and restart body."

"Branden Nelsen" wrote in message
...
Unfortunately I am not sure what the power output of my Alt is on that
car.

As far as replacing the battery with a Optima or Stinger, Unfortunately
where BMW place's the battery in their cars (Trunk) it requires a battery
that resembles a 'stout' Marine battery, so a normal Yellowtop type
battery wont fit in the stock area. There is however a nice place to
install a second battery above the stock one if I go that route.

Main reason I want a second Battery or a cap is that I don't want to over
tax the Alt or standard battery as I have heard either one is pretty
costly to replace.

-Branden


Adding a second battery will over tax the Alt since it will work twice as
hard to keep 2 battery's charged

That is a good point... Hmm..

Looking at the 'Standard' Stock Equipment on that car it has:

-120 amp alternator
-90 amp battery

As far as I know the Amp has not been changed. I do however think the
battery has, as it has a Interstate battery in there right now I believe. So
maybe just running with it all and seeing if something *might* break, would
be a better idea the over doing it and actually hurting it more overall.

Would a Cap effect it as much as a battery if I used that?

-Branden



"e-nigma" wrote in message
news:kBr7f.15758$hP6.1548@trnddc05...

"Branden Nelsen" wrote in message
...
Unfortunately I am not sure what the power output of my Alt is on that
car.

As far as replacing the battery with a Optima or Stinger, Unfortunately
where BMW place's the battery in their cars (Trunk) it requires a battery
that resembles a 'stout' Marine battery, so a normal Yellowtop type
battery wont fit in the stock area. There is however a nice place to
install a second battery above the stock one if I go that route.

Main reason I want a second Battery or a cap is that I don't want to over
tax the Alt or standard battery as I have heard either one is pretty
costly to replace.

-Branden


Adding a second battery will over tax the Alt since it will work twice as
hard to keep 2 battery's charged

"Branden Nelsen" wrote in message
...
That is a good point... Hmm..

Looking at the 'Standard' Stock Equipment on that car it has:

-120 amp alternator
-90 amp battery

As far as I know the Amp has not been changed. I do however think the
battery has, as it has a Interstate battery in there right now I believe.
So maybe just running with it all and seeing if something *might* break,
would be a better idea the over doing it and actually hurting it more
overall.

Would a Cap effect it as much as a battery if I used that?

-Branden



A cap will not effect the Alt. It can help the bass response.
Whenever the bass hits the battery voltage drops a little.
The Cap discharges at that time to keep the battery voltage steady.

Ah, so im prolly beating a dead horse on adding anything, to help with over
all load on the system. Also looking at that FAQ (still reading though) it
would be better to upgrade the Alt in this case then to add a cap/battery to
the system.

-Branden

"e-nigma" wrote in message
news:gAs7f.6206$tl5.4474@trnddc02...

"Branden Nelsen" wrote in message
...
That is a good point... Hmm..

Looking at the 'Standard' Stock Equipment on that car it has:

-120 amp alternator
-90 amp battery

As far as I know the Amp has not been changed. I do however think the
battery has, as it has a Interstate battery in there right now I believe.
So maybe just running with it all and seeing if something *might* break,
would be a better idea the over doing it and actually hurting it more
overall.

Would a Cap effect it as much as a battery if I used that?

-Branden



A cap will not effect the Alt. It can help the bass response.
Whenever the bass hits the battery voltage drops a little.
The Cap discharges at that time to keep the battery voltage steady.

Branden Nelsen wrote:
Unfortunately I am not sure what the power output of my Alt is on that car.

As far as replacing the battery with a Optima or Stinger, Unfortunately
where BMW place's the battery in their cars (Trunk) it requires a battery
that resembles a 'stout' Marine battery, so a normal Yellowtop type battery
wont fit in the stock area. There is however a nice place to install a
second battery above the stock one if I go that route.

If you do that, be sure to use a proper battery isolator - most
"auto-parts superstores" should sell them for RVs, which typically use a
second battery for camper accessories.

Main reason I want a second Battery or a cap is that I don't want to over
tax the Alt or standard battery as I have heard either one is pretty costly
to replace.

Unfortunately, the current has to come from somewhere in the first
place, and that place is your alternator. The battery(ies) only store
it. If the alt can't supply enough, no number of batteries will help -
they'll just take longer to drain. And if you're overloading the
alternator, you'll probably end up having to replace it anyway, probably
AFTER you're stranded somewhere.

A cap won't create any extra current either - like a battery, it only
stores energy; the idea is that it can release large "shots" of current
quickly for loud spikes, nothing more.

Really, you're looking at the process backward. The first thing to do
is make sure your alternator can provided the current necessary for your
entire car. Put your system in, get it tuned up, then start the car
and, running at idle, turn on ALL the accessories (lights, fan, A/C,
defroster, wipers, etc.), then crank up the stereo. If your lights dim
significantly with the bass hits, then you're pulling more current than
the alternator can supply (some flickering is okay). Upgrade the
alternator FIRST, to avoid problems later - as I say, if you run on the
stock alt too long under these conditions, you'll likely have to replace
it soon anyway; better to do it when it's NOT inconvenient.

A second battery at this point will help ensure you don't end up stuck
somewhere unable to start the car - an isolator will allow the system to
run only off the secondary battery so it won't drain the primary, and
the car's other electrical won't drain your secondary battery.

If you find the amps "dropping out" or going "soft" on the big bass
hits, that's the time to add a cap.



-Branden



"Scott Gardner" wrote in message
...

On Mon, 24 Oct 2005 13:22:26 -0500, "Branden Nelsen"
wrote:


I am going to be doing my first nice install in any of my cars in my new
(to
me) 99' 528i. I have a Directed 1100d (old style Black and Silver). I am
going to be going with 4 of the Kicker S8L5's in a sealed box. I love the
sound of the current S10L5 I have but want a bit more sometimes. Now I
think
I have it measured correctly for Amp/Sub ratio. That Amp should put out
exactly the right amount for those 4 subs in a 1ohmish load.

My question is:

I REALLY don't want to jack up the battery or any of the power devices or
OE
cabling in the car, I haven't really cared in the past with my Junker cars
but this one I want to take car of. My question is, with that type of
setup.
Should I buy a Optima Yellow top and install that into the car also? Or
would a standard 1 Farad Cap or 2 do the job well enough to cover
everything.

If you need anymore info on the subject please reply and ill try to
include
that.

If your alternator won't provide enough current to supply your car's
electrical system and your stereo needs, with a little left over to
keep the battery topped off, then no battery or capacitor will help
you.

That being said, I would replace your battery on general principle if
it's the original battery, and an Optima or Stinger is as good a
choice as any.

A 1999 BMW will probably have a pretty stout alternator as standard
equipment, so I'd install the stereo and see if you have any problems
with you battery discharging, lights flickering/dimming, etcetera, and
then go from there.

Unless you're cranking the stereo at full blast all the time, the
*average* current requirements for your stereo will be surprisingly
low, even for a "big" stereo.


--
Scott Gardner

"Invalid thought detected. Close all mental processes and restart body."






---
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Branden Nelsen wrote:
Ah, so im prolly beating a dead horse on adding anything, to help with over
all load on the system. Also looking at that FAQ (still reading though) it
would be better to upgrade the Alt in this case then to add a cap/battery to
the system.

Actually, 120 amps is a pretty hefty alternator; you may be okay with
that.

Perform the test I described, or better yet, have an alternator shop
check your current draw while you have everything on and cranked up:
they can tell you how much current you're actually drawing, and can test
the condition of your charging system while you're at it.

-Branden

"e-nigma" wrote in message
news:gAs7f.6206$tl5.4474@trnddc02...

"Branden Nelsen" wrote in message
...

That is a good point... Hmm..

Looking at the 'Standard' Stock Equipment on that car it has:

-120 amp alternator
-90 amp battery

As far as I know the Amp has not been changed. I do however think the
battery has, as it has a Interstate battery in there right now I believe.
So maybe just running with it all and seeing if something *might* break,
would be a better idea the over doing it and actually hurting it more
overall.

Would a Cap effect it as much as a battery if I used that?

-Branden



A cap will not effect the Alt. It can help the bass response.
Whenever the bass hits the battery voltage drops a little.
The Cap discharges at that time to keep the battery voltage steady.






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Excellent! I think that is what ill do. I really appreciate everyone's
advise it has helped me allot on this decision..

Now to get the Sub's and build a custom box.

-Branden


"Matt Ion" wrote in message
news:%ft7f.296507$1i.94299@pd7tw2no...
Branden Nelsen wrote:
Unfortunately I am not sure what the power output of my Alt is on that
car.

As far as replacing the battery with a Optima or Stinger, Unfortunately
where BMW place's the battery in their cars (Trunk) it requires a battery
that resembles a 'stout' Marine battery, so a normal Yellowtop type
battery wont fit in the stock area. There is however a nice place to
install a second battery above the stock one if I go that route.

If you do that, be sure to use a proper battery isolator - most
"auto-parts superstores" should sell them for RVs, which typically use a
second battery for camper accessories.

Main reason I want a second Battery or a cap is that I don't want to over
tax the Alt or standard battery as I have heard either one is pretty
costly to replace.

Unfortunately, the current has to come from somewhere in the first place,
and that place is your alternator. The battery(ies) only store it. If
the alt can't supply enough, no number of batteries will help - they'll
just take longer to drain. And if you're overloading the alternator,
you'll probably end up having to replace it anyway, probably AFTER you're
stranded somewhere.

A cap won't create any extra current either - like a battery, it only
stores energy; the idea is that it can release large "shots" of current
quickly for loud spikes, nothing more.

Really, you're looking at the process backward. The first thing to do is
make sure your alternator can provided the current necessary for your
entire car. Put your system in, get it tuned up, then start the car and,
running at idle, turn on ALL the accessories (lights, fan, A/C, defroster,
wipers, etc.), then crank up the stereo. If your lights dim significantly
with the bass hits, then you're pulling more current than the alternator
can supply (some flickering is okay). Upgrade the alternator FIRST, to
avoid problems later - as I say, if you run on the stock alt too long
under these conditions, you'll likely have to replace it soon anyway;
better to do it when it's NOT inconvenient.

A second battery at this point will help ensure you don't end up stuck
somewhere unable to start the car - an isolator will allow the system to
run only off the secondary battery so it won't drain the primary, and the
car's other electrical won't drain your secondary battery.

If you find the amps "dropping out" or going "soft" on the big bass hits,
that's the time to add a cap.



-Branden



"Scott Gardner" wrote in message
...

On Mon, 24 Oct 2005 13:22:26 -0500, "Branden Nelsen"
wrote:


I am going to be doing my first nice install in any of my cars in my new
(to
me) 99' 528i. I have a Directed 1100d (old style Black and Silver). I am
going to be going with 4 of the Kicker S8L5's in a sealed box. I love
the
sound of the current S10L5 I have but want a bit more sometimes. Now I
think
I have it measured correctly for Amp/Sub ratio. That Amp should put out
exactly the right amount for those 4 subs in a 1ohmish load.

My question is:

I REALLY don't want to jack up the battery or any of the power devices
or OE
cabling in the car, I haven't really cared in the past with my Junker
cars
but this one I want to take car of. My question is, with that type of
setup.
Should I buy a Optima Yellow top and install that into the car also? Or
would a standard 1 Farad Cap or 2 do the job well enough to cover
everything.

If you need anymore info on the subject please reply and ill try to
include
that.

If your alternator won't provide enough current to supply your car's
electrical system and your stereo needs, with a little left over to
keep the battery topped off, then no battery or capacitor will help
you.

That being said, I would replace your battery on general principle if
it's the original battery, and an Optima or Stinger is as good a
choice as any.

A 1999 BMW will probably have a pretty stout alternator as standard
equipment, so I'd install the stereo and see if you have any problems
with you battery discharging, lights flickering/dimming, etcetera, and
then go from there.

Unless you're cranking the stereo at full blast all the time, the
*average* current requirements for your stereo will be surprisingly
low, even for a "big" stereo.


--
Scott Gardner

"Invalid thought detected. Close all mental processes and restart body."






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i wish i had a 120a alt...mines 90.
i guess you could race your motor alil at standing stlll or before you
start out could help.
not flooring it for 10minutes..just race it alil for a minute...

"Branden Nelsen" wrote in message
...
The reasoning I am wanting the Four 8's instead of Two 10's is that with
the
L5 series by kicker (Square subs) the 8" equals the surface area of a
standard 10" round sub. In this setup I would be running the equivalent
surface area of Four 10"s in a sealed box.

It is more complicated than that, to a point you may be running technically
the same surface area but if you're thinking that equates to output you've
only got half the story.

Also with 8" L5 they only require
a .33ft^3 box per sub. In my 528i ill have those 4 in a total 2ft^3 box
with
each having their own .5ft^3 box inside the box as a "whole". This will
Fit
nicely in the front part of the trunk and still leave me access to a
useable
spare tire while having a nice professional looking install.

Now that's a good reason, but there is no reason you shouldn't be able to
get, say a single 12" sub, in a 1cubic foot (notice half the size) box
instead of 4 8" subs, have just as much output, and pay less money. If
you're concerned about space, cost, and simplifying things I would look into
that route.

Les

"e-nigma" wrote in message
news:gAs7f.6206$tl5.4474@trnddc02...
A cap will not effect the Alt. It can help the bass response.
Whenever the bass hits the battery voltage drops a little.
The Cap discharges at that time to keep the battery voltage steady.


*Can* being the key word. Won't is the word I would typically choose to use.
The cap discharges very quickly, yet charges relatively slow. So, the likely
hood of it making any audible difference is about impossible. Helping with
light dimming, maybe....Besides don't you think the amp manufactures already
put enough in?

Les

Les wrote:
"e-nigma" wrote in message
news:gAs7f.6206$tl5.4474@trnddc02...

A cap will not effect the Alt. It can help the bass response.
Whenever the bass hits the battery voltage drops a little.
The Cap discharges at that time to keep the battery voltage steady.



*Can* being the key word. Won't is the word I would typically choose to use.
The cap discharges very quickly, yet charges relatively slow. So, the likely
hood of it making any audible difference is about impossible. Helping with
light dimming, maybe....Besides don't you think the amp manufactures already
put enough in?

Unless you're "separating" input and output voltages with a resistor and
diode or something, a cap should charge and discharge at exactly the
same rate.


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i ws thinking if discharging at less than a tenth of a second n charging
back in just over a tenth of a second to half a second..is slower i
guess it is slower.....

"Matt Ion" wrote in message
news:LcE7f.299062$oW2.295456@pd7tw1no...
Les wrote:
"e-nigma" wrote in message
news:gAs7f.6206$tl5.4474@trnddc02...

A cap will not effect the Alt. It can help the bass response.
Whenever the bass hits the battery voltage drops a little.
The Cap discharges at that time to keep the battery voltage steady.



*Can* being the key word. Won't is the word I would typically choose to
use.
The cap discharges very quickly, yet charges relatively slow. So, the
likely
hood of it making any audible difference is about impossible. Helping
with
light dimming, maybe....Besides don't you think the amp manufactures
already
put enough in?

Unless you're "separating" input and output voltages with a resistor and
diode or something, a cap should charge and discharge at exactly the same
rate.

Not only that, but, if you isolate it with a Diode to ensure it will only
supply surge current to the amp as opposed to the horn, AC compressor
clutch, and blower inrush, you will be dropping the charge voltage by around
..7V due to PN junction loss. More harm than good.

Chad

"Chad Wahls" wrote in message
...

"Matt Ion" wrote in message
news:LcE7f.299062$oW2.295456@pd7tw1no...
Les wrote:
"e-nigma" wrote in message
news:gAs7f.6206$tl5.4474@trnddc02...

A cap will not effect the Alt. It can help the bass response.
Whenever the bass hits the battery voltage drops a little.
The Cap discharges at that time to keep the battery voltage steady.



*Can* being the key word. Won't is the word I would typically choose to
use.
The cap discharges very quickly, yet charges relatively slow. So, the
likely
hood of it making any audible difference is about impossible. Helping
with
light dimming, maybe....Besides don't you think the amp manufactures
already
put enough in?

Unless you're "separating" input and output voltages with a resistor and
diode or something, a cap should charge and discharge at exactly the same
rate.

Not only that, but, if you isolate it with a Diode to ensure it will only
supply surge current to the amp as opposed to the horn, AC compressor
clutch, and blower inrush, you will be dropping the charge voltage by
around .7V due to PN junction loss. More harm than good.

Chad


What if it's a germanium, and how big is a diode that handles that much
current (60-100 amps)?

bob wald wrote:
i ws thinking if discharging at less than a tenth of a second n charging
back in just over a tenth of a second to half a second..is slower i
guess it is slower.....

Nope. A cap charges and discharges according to the RC formula -
resistance times capacitance. Charge and discharge times are identical.
There might be a few milliseconds' variation because of the longer
wire to the battery having more resitance than the shorter one to the
amp, but it should be insignificant.


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e-nigma wrote:
"Chad Wahls" wrote in message
...

"Matt Ion" wrote in message
news:LcE7f.299062$oW2.295456@pd7tw1no...

Les wrote:

"e-nigma" wrote in message
news:gAs7f.6206$tl5.4474@trnddc02...


A cap will not effect the Alt. It can help the bass response.
Whenever the bass hits the battery voltage drops a little.
The Cap discharges at that time to keep the battery voltage steady.



*Can* being the key word. Won't is the word I would typically choose to
use.
The cap discharges very quickly, yet charges relatively slow. So, the
likely
hood of it making any audible difference is about impossible. Helping
with
light dimming, maybe....Besides don't you think the amp manufactures
already
put enough in?

Unless you're "separating" input and output voltages with a resistor and
diode or something, a cap should charge and discharge at exactly the same
rate.


Not only that, but, if you isolate it with a Diode to ensure it will only
supply surge current to the amp as opposed to the horn, AC compressor
clutch, and blower inrush, you will be dropping the charge voltage by
around .7V due to PN junction loss. More harm than good.

Chad



What if it's a germanium, and how big is a diode that handles that much
current (60-100 amps)?

Battery isolators are generally just a pair of big diodes like that,
they're maybe the size of a deodorant stick. Frankly, this is not
something you'd normally do, or want to do, so it's really moot.


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"e-nigma" wrote in message
news:IuL7f.15860$Io4.817@trnddc06...

"Chad Wahls" wrote in message
...

"Matt Ion" wrote in message
news:LcE7f.299062$oW2.295456@pd7tw1no...
Les wrote:
"e-nigma" wrote in message
news:gAs7f.6206$tl5.4474@trnddc02...

A cap will not effect the Alt. It can help the bass response.
Whenever the bass hits the battery voltage drops a little.
The Cap discharges at that time to keep the battery voltage steady.



*Can* being the key word. Won't is the word I would typically choose to
use.
The cap discharges very quickly, yet charges relatively slow. So, the
likely
hood of it making any audible difference is about impossible. Helping
with
light dimming, maybe....Besides don't you think the amp manufactures
already
put enough in?

Unless you're "separating" input and output voltages with a resistor and
diode or something, a cap should charge and discharge at exactly the
same rate.

Not only that, but, if you isolate it with a Diode to ensure it will only
supply surge current to the amp as opposed to the horn, AC compressor
clutch, and blower inrush, you will be dropping the charge voltage by
around .7V due to PN junction loss. More harm than good.

Chad


What if it's a germanium, and how big is a diode that handles that much
current (60-100 amps)?


Although Germanium diodes have a lower voltage drop (around .3V) they cannot
handle the current needed for rectification and switching. Germanium
devices are generally used for small signal detectors in RF equipment, They
are also quite sensitive to heat and vibration.

Unfortunately there is no way around the drop other than increasing the
voltage before the diode. In most applications the forward voltage drop is
not critical because they are used as rectifiers and the circuit can be
designed around the drop. But in a simple "check" valve situation in an
automobile it is tough to design around. most people will not to lose
upwards of 6% of the available voltage when one can employ a battery with
very low internal resistance and proper sized supply wire.

As for size of diode, they aren't that huge, they DO need to be mounted on a
metal plate, the plate is not only used for heatsinking but also for
electrical connection. Often times several are used so the plate becomes a
common connection point. Here's a datasheet for a 200A device at 35V, I
always overestimate the current and voltage of a diode by over 100%. There
are sooo many variables in a car it's worth the money, Fortunately if it
fails it will fail short and the system will still work, as opposed to
failing short in a rectifier application :()

http://www.irf.com/product-info/data...200hf40pvl.pdf

Chad

Here are a couple of other good links on this topic:

http://www.bcae1.com/charging.htm
http://www.bcae1.com/chargin2.htm
http://www.bcae1.com/capacitr.htm


--
Jethro

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I. Care wrote:


If you would like to see a virtual demonstration of charge/discharge:

http://www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?t=48


That's really cool!


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