lorettaboy

I would like to add a capacitor to my system, but have a question.
First off, the car is a '92 buick LeSabre, the amp is a RF power 500.2, the sub is an Infinity perfect 12. I am currently using 8 ga. power cable. Is this cable large enough to allow a capacitor to be hooked up?
Thanks

FusionMadsen

iTrader: (4)

Yes it is.

DesolataX

iTrader: (1)

Why do you need a capacitor? Lights dimming? A cap won't do anything to fix that. Do the big 3 then see if you still need the cap.

d4rin

Maybe a simple cap will help with that. Without doing the "Big 3".

They make Capacitors for a reason.

Starterwiz

That amp has a 50 amp fuse.
With an average of 22 ft of 8 ga wire including the ground, you'll be losing about 1.5 volts.
Step up to 4 ga, and do the big three.

http://www.powerstream.com/Wire_Size.htm

zinger002

iTrader: (1)

with 2/0 guage wire and about 17 feet how much voltage drop will i encounter if im running 800Wrms?

FusionMadsen

iTrader: (4)

Probably a volt, but if you cut a foot or two off that then the drop will be remote. It seems like the difference in the 15-18ft range is quite high compared to other lengths.

Starterwiz

800 watts RMS on a typical class D amp will draw over 1000 watts, or over 85 amps.
Using the calculator I provided, .5 volts or more.
Drop to 14ft, and it's still about .4V.

Remember to add all the wire in the circuit tho.....ground, battery to chassis ground, alt to chassis ground, and alt to battery line.
You'll have a lot more than 17 feet.
Then add in the resistance of all the connections, and fuses, and....well you get the picture. Resistance is a VERY BAD thing when it comes to big power.

Here's some simple math.

R=V/I
R(amp)=12/100 = 0.12 Ohms. The amp must show 0.12 Ohms of resistance to a 12 Volt source to be able to draw 100 amps of current in.

The voltage drop across two series resistors is divided proportionaly between the resistances.

If the wire has 0.12 Ohms, and the amp has 0.12 Ohms, then the amp gets 6 volts, and the wire gets 6 Volts.

Yes you read that right....crappy wire and connections and you're running at 1/2 the voltage you need.

Ideally, you want 1/100th the resistance of your amp on the wires. Or 0.0012 Ohms.
Practically, you will probably settle for more resistance/larger voltage drop.

If I lost you.....read my sig lol

Starterwiz

Just to take it a step further in support of the Big 3:

If that 800 watt amp has a good regulated power supply, it will still try to put out 800 watts, even tho it's only getting 6 Volts.

I= P/V
I= 1000/6
I =166 amps
Did you see your lights dim yet?

But wait.....if the amp is now drawing 166 amps....then it's resistance is now LESS than the wire, so it's not getting 6 Volts any more....maybe 3 volts.

Now are they dimming???

Oh crap....3 volts means 333 amps.....Um...that wire must be getting pretty warm.

JohnVroom

Please dont take good advice and contradict it Darin, he never actually said he had a problem... he just wants a cap
And yes they make capacitors for a reason and that reason is to make money! The cap could have value but not in a system that has more significant issues (and the system in question does not necessarily have any huge issues).

I would recommend a second 8 gauge or a 4 gauge run of wire to the amp, this will cost less than the cap and do more to help the amp put out rated power. You have an excellent SQ system BTW it should sound good and be plenty loud. Also your car has some age to it check your ground and power wires to the battery. Also is the battery fresh or is it > 10 years old?

And back to the Q as asked; yes you can hook up a cap with 8 gauge wire