does any one know any thing about capacitors?

id like to get one to help power my system,
2 amps + head unit = 1150watts
is putting a strain on my battery and alternator,

im thinking i should get a unit that is rated between
1 farad, and 25 farad,
but not shure what size is right for me,
or what makes a capacitor good or bad,

fill me in please if you know anything about them.
thanks
and happy holidays!

 

Caps don't power anything. They help with transient peaks by helping to stabilize voltage a bit, but at the end of the day, your battery and alternator still have to power the system including the capacitor. In other words, a cap can add even more strain to an already-strained system. There are better ways to spend your money, such as high-quality amplifiers with good power supplies.

 

Look into doing the big3

 

Big 3 = a $20 mod that will yield significant results.

What is the capacity of your alternator? For your size system, you should be running at LEAST 150 amps. ideally 160-180 will keep you safe and prevent strain.

 

how would the cap strain anything ? It cannot. high reserve capacity AGM battery (optima) and a cap would not hurt, although may not be necessary in this case. st

 

A capacitor is esentially a small-capacity/quick-discharge battery. When it discharges, it has to be re-charged. If your alternator can't maintain a good "floating" current, a cap will just add to the list of things to be recharged.

The High reserve battery you speak of is the Optima Yellow top (aka deep cycle) battery. If you get one of these I HIGHLY reccomend a cap because the deep cycle batteries are slow to discharge and musical bursts/bass hits will suffer. I will be upgrading my optima red top to one of these soon.

 

my alternator is ( stock ? ) I guess.
it reads on the dash about an average of 13.5 volts when driving around with no accesorys on ( no headlights / stereo / wipers ..... )
when cold at idle ( 1200 rpm = 14 ish volts ) and once car is at temp or running for a while vots at idle ( 650 ish rpm = 12.7 to 13.5 v ) if I step on the gas a bit and bring rpm up to 800 volts are around 13.7

when I have the head lights on at night, and im cranking the system, I see voltage go down to low 12's or just 12v flat- and get nervis and turn down - or off the stereo.

I know that a battery needs about 13v to keep it self charged up all the time, so im thinking maby I should check out my alternator output with some kind of digital multi meter.
I have one but dont realley know how to use it , or its propper settings to measure around 80 to 150 amps. hmmmmm....

maby also I should check in to a higher out put alternator, maby one from powermaster, or equivlent.
I do like driving with my music on, but I dont want to go crank it up only to have a dead battery and a car that wont start.
that would suck.

 

Do the "big 3" and then see if you have the same problem. Only afterwards would I consider an alternator upgrade.

Mark

 

www.4alterstart.com

these guys built the alternator for my old truck. Great service and excellent price. I got a CS144 rated at 180 amps for ~$200 shipped. Direct bolt on and no problems. Give them a call ans see if they have somthing for your application.

 

Don't waste money on a cap and its unlikely you will need a HO alternator with only 1200 watts.

big 3 makes a big difference in these cars. And make sure you have proper sized power and ground wires with a very low resistant ground point. Some guys run the ground back to the battery. Thats fine as long as the ground from the battery to the frame is also upgraded.

 

I'm new to the audio side of things. What constitues a "very low resistant" ground point?

 

You can test your ground with an ohm meter. The lower the reading the better

A common ground point is the seat mounting bolt. It works, but is not the best. On the c5 and c6, there is a factory ground in the b pillar trim on the passenger side. Its better if you compare the two with a meter.

 

just so I am 100% certan, this is the propper way to do the big 3?
- I found this on the rockford fosgate support message boards, -

if you dont know how to do the BIG 3 here it is..
Step.
1.open hood
2.unhook and remove battery
3.remove the ground from the vehicle and cut 1/0 gauge wire to that length
4.ive been suggested this method and i know meade uses it, but when attaching the 1/0 to the terminals fill in the terminal where it holds the wire with solder..get it hot and liquid and put the wire in after stripping about an inch or so off.
5.repeat for the wire that goes from the alternator to the battery.
6.make sure you do both grounds. theres one that goes to the chassis and one that goes to the transmision
7. clean battery with baking sode mixed with water. will get al the acid and such off of it.
8.attach new wires and put battery back in.

in short here it is. Ground from the battery to chassis and battery to engine upgraded to big wire.
wire from alternator to battery made bigger.. it usually is better to fuse this wire.


does this seem about right?
wonder where I can find some good thick wire to do this with....
and curious to what guage the alternator to battery charge wire is to be replaced with, and what # fuse?

 

Here's how I did the "Big 3" actually "Big 4".

1) Make four lengths of either 4awg, 1awg or 0awg wire and connect the first one from the battery positive to the factory alternator battery connection. You don't need to remove the factory alternator power wire just connect the new wire onto the stock power connector.

2) Connect the second new wire from the battery negative to the engine block or alternator frame.

3) Connect the third new wire from the battery negative to the vehicles frame.

4) Connect the last new wire from the transmission body to the vehicles frame.

 

Brian84,

Look in the C5 FAQ above... almost at the bottom of page three you will see where Pentavolvo does a good write up on it.

http://forums.corvetteforum.com/show...1117959&page=3

You can also find a write up by DPG here:

http://forums.corvetteforum.com/show...ighlight=big+3

The "Big 3" is basically the same for all vehicles. You want to maximize the conductor (wire) size between the following points:

Main ground(s): Chassis to battery & chassis to engine block. The big part of this is providing a good ground for your charging system to your battery, while tying in the chassis in the process. Some folks even run a dedicated ground from one of the alternator bolts to the chassis just to make sure that the electrical path from the alternator and the rest of the car is 100%. Your mileage may vary.

Power: Alternator to battery. I personally would run fuses at both ends, as both are considered 'sources' of power... but others may have a different opinion about that.

(I have had a bad experience with a power wire and headers... so I err on the side of caution. )

As for the 'right' size wire to use... that all depends on the length of wire and the amount of current you intend to draw. For my system, I wouldn't need more than 4 AWG, but your application may need more than mine, so size it accordingly.

I am not familiar with the C4 enough to understand why you need a transmission ground... but if it's part of the stock electrical system and a current conductor for the rear of your car, then upgrade this as well.

Hope this helps.

Mark

 

cool, that does not sound too hard to handle.

maby the transmision is a key part of the ground system because the c4 frame it self is not all that great of a conductor for ground.
that or the fact that the tranny may be computer controled would mean it needs a good ground for it self.

its cool tho.
thanks all.

Ill be shure to take pics when I do the big 3 and post em up so yall can see.

 

Works better than a cap.