power caps

[vvega]

i left the audi in dustry just as the d class amps were comming in but we were lead to belive that they would outdate the need for a power cap in most installs
ive recently bought a fusion 1000d d class amp
its 1000w rms at 12v and 1400rms at 14v...@ 1 ohm
problem been i now have a issue with dimming lights
i have O guage power cable in my car and have a 750 cca wet cell
my earth is also O guage both to may battery and to my amp

i also run a punch 800a4 for my mains 125rms x 4 @ 12v

soi whats the deal are caps now required again or is there another way to get around this issue(besides not useing my lights)

maybe this is just the wrong place to ask but please if you dont know dont want to hear your guess's
(unless you have a sound backround )

thanks
v

[Alex B]

Not required at all.

[DeeCee]

whats the output of the alternator - if you are running an upgraded electrical system (which is great ) your alternator may not be producing enough power to the battery

also check all earths as well.. but i suspect that you'll have to look at upgrading the alternator.. you could run a cap.. but there are really no major benefits with running a cap

[vvega]

alternater is sitting on 14.4 volts when i get bass spikes then it dipps off to 12.8 so i would be losing a hell of a lot of wattage and im guessing i why my bass is sounding a bit flat
aside from the brushes and regulator been brand new its just the stock camry alternator ..120 amp i belive


v

[Alex B]

What battery are you running?

[vvega]

750 cca genuine toyota one so a xcide
just a wet cell

[DeeCee]

not the voltage output vvega - the amps produced by the alternator
if the ampere output is low on the alternator then it will affect the rest of the electrical system.. meh - just get a cap

[nmemr2]

it almost sounds like you guys are a bit against caps
apart from being yet another costly piece of equiptment, whats the problem with them,
i only ask as im looking at getting caps with my upgrading of my system

[Alex B]

As far as i can tell from reading the ice forums, they do sweet $&#$% all.

[DeeCee]

haha - considering that i know both the theory and reality of caps and how they don't work in theory and work in reality is funny - thats why i keep saying "look at your alternator"

Right - lets get down to it then:
vvega - you have a monoblock - whats the amp loaded down to for the subs? ie 4 ohm, 2 ohm or 1 ohm?

Lets have a look at the specs

CEA 2006 OUTPUT POWER @ 14.4VDC
575 Watts RMS per channel @ 4 Ohms and 1%THD+N
S/N > 64 dBA (reference 1 watt into 4 Ohms)

ADDITIONAL POWER RATINGS 14.4VDC
999 Watts RMS per channel @ 2 Ohms and 1%THD+N
1400 Watts RMS per channel @ 1 Ohms and 1%THD+N

You will most likely never see the full power out of the amplifier unless loaded down to 1ohm and to the point of clipping the sub.

Music has peaks and troughs, ie high volume and low volume points of music, so the power going to the subs is going up and down all the time, therefore you may be drawing a fair amount of power.
But because the power being drawn from the battery is fluctuating all the time the alternator doesn't have time to energise because the power taken away from the bigger battery is a smaller load.

A cap works to increase the load on a battery to ensure that the alternator energises - hence: caps work in this instance with a small battery and subs playing.. BUT caps have a minimal to nil effect when used with a large battery

CAPS PUT LOAD ONTO A SYSTEM - they do not add to the system -they are designed to take away from the system

Moral of the story? You've upgraded the battery and electrical system - look at the alternator instead of looking for a cap to use as a bandaid on a poor electrical charging system cos the cap will just act as a large voltmeter

And if you do look decide that your problem can be solved by a cap then look for one with a low ESR (equivalent series resistance)

This will point you in the right direction and again - you need to ensure that your electrical system is grounded properly and the potential of the system is up to scratch before you go looking at the alternator and capacitors

Dave

[DeeCee]

haha - silly me for not reading properly - you have a stock 120 alternator..

check the loading on the amp and get back to me - i need more info to figure this one out

[vvega]

amp is loaded to 1 ohm
2 x 4ohm dvc subs in parallel mono

v

[vvega]

lol at large voltmeter
my view on caps is that they allow a more constant voltage normally....
im not saying they give 14.4 all the time but they keep it the same
...if that makes sence

finally i also understand why you get drag on batterys of a wet cell (chemical stored to electrical potental)...
maybe i sould also look at going to a gel cell :S

if the battery can suppy the amperage required then technicaly the alternator only has to supply the extra voltage in case of spike draw........
this is how we ere taught at the alpine block course i did back im the day......lol

i imagine they way things are perceved is different these days


i do have a 1uz alternator here (180amp) perhaps i sould look at useing that

v

[Monster_Magnet]

Back when I was doing sound offs class d's were rare at the time.

Most people told me they were running 1 farad caps for every 1000 watts but they wern't running class D's.

But as to class D wouldn't you be more inclined to run a cap??

They are after all a very hefty bit of kit in my mind to run with out a cap??

[the fallen303]

i thought class D's when they came out were a lot more efficient than the other amps? i remember when infinity first released their class D's, they could be run in a smaller environment with less airflow due to not producing as much heat. i've been out of the loop for a few years as well

[vvega]

amp is loaded to 1 ohm
2 x 4ohm dvc subs in parallel mono
....
...
reading that again it isnt very clear

both coils are wired in parallel per sub
then both subs are wired in parallel
im sure you understood the first comment but just to be sure
amp is loaded @ 1 ohm



v