While this is out of place, and should likely be in the classifides, I've got a 150A Alternator for a non-vtec civic for $200. There was a difference between the US and Canadian Alternators and I'm SOL. It's only been tested, never used. 150A should be more than enough power for a 1K amp, unless of course you plan on deafening yourself.....

 

I've got lot's of stereo stuff in my crx. I installed it all with two one farad caps. The amps still clipped off when turned to loudly because of the lack of power. I then installed an optima yellow top battery. That solved my problem. Like somebody posted above, the caps won't really supply the power you need unless you've got a strong power supply(good battery and/or alternator). I have'nt played my stereo without the caps, so i could'nt tell you if they did any good or not. I'm sure they help to a certain degree, or else, they would'nt make them. Also, a capacitor will do no good if it's not installed as closely to the amp as possible. At least that's what i read somewhere.

 

Capacitors hold a charge for a certain period of time, even after the power is cut off, and it dosnt take much to charge them... They are not only charged while they are supplied with voltage... They act as buffers for energy basically... And how they work on your stereo is, while your stereo is on and your battery isnt being strained (no loud bass hitting, and the amp trying to pull tons of power from the battery), the capacitor is being charged upto its capacity (measured in farads)... And once its full it continues to hold that amount of power, and when the amp draws more power than you battery can give, the capacitor supplies the amp with the required power, and then when the battery isnt being strained again, it will charge back up and store the energy until the amp requires it again... It basically just acts as a buffer for energy...

They are the main reason, why your not supposed to open up electronics, even after you unplug them...

And to back up what I am saying...

From this link:

http://www.uoguelph.ca/~antoon/gadgets/caps/caps.html

Also note that a weak battery, already being drained, will probably not be enough to power the whole system... Hence why Tankard still had a problem, and had to replace his battry... So replacing the battery with a new one, will definately help... But the capacitor will help the new battery to not become so less drained...

So basically, both sides are right to a point...


But yea, if your lights dim, its a sure sign you might need one... Either that, a new battery, or an alternator... They will both solve the not enough current/power problem... Remember, anytime u add an electrical component, you are working your alternator harder, so it does have a better chance of dying out sooner than it would normally... But me, Id worry about that when the time comes, and just get a capcitor now, if that dosnt help then Id get a new battery... And since capacitors all do the same thing, brand name is not an issue... Size is, and 1.5 farad is plenty...

 

Well that was a nice lengthy post, but once again you are promoting something that you shouldn't be!
I am going to try and sum this up as blatantly as possible, and I think that WiLL is leading you in the right direction.
A stiffening capacitor is not made to stop the dimming of your lights while playing high power audio equipment.
Yes, in some cases it helps the dimming of the lights because it stores charge.
"Stiffening capacitors are used as a sort of electrical shock absorber. As voltage starts to rise, the capacitor will absorb energy which will tend to keep the voltage from rising as quickly as it otherwise would."
If you want to correctly fix the light dimming problem on your high power audio system, upgrade your alternator. As WiLL said Honda doesnt really supply their cars with a very big alternator at all. They dont build the cars with large audio systems in mind.

 

i'd rather have an extra battery than a cap, but thats just me

 

Not to resurect the smoldering coals of a dead flame thread, but I figured it was only fair to somewhat explain what a cap does and what situations it will and will not fix as this is the first working hit off of google when looking for what cap size you need.

A capacitor is very much like a fast-acting battery. Under no-load conditions, a cap will charge up to the supply voltage it is connected to. In the case of your car battery and alternator setup, it will charge to a little over 12V. If a sudden load is applied to the system, the battery and alternator don't "sit back while the cap does the work", they both still supply whatever energy they can. The cap simply supplies energy faster so it appears to take load off the system. Once the cap drains down (which happens --very-- quickly), it is useless until it recharges again. This recharge takes a finite (but small) amount of time and while it is charging, the cap is taxing your battery and/or alternator.

As was said before, a cap does not "add evergy to the system" a cap "buffers" or "filters" the energy in a system. In electronics terms, "a capacitor resists a change in voltage across its terminals".

So, as for what a cap can do to help you:

If you turn on your amp(s) and your lights dim and stay dim, a cap isn't going to help you. You have a constant draw that is more than your system can handle. You need to upgrade your alternator no matter what and your battery if you plan on using your stereo without the car running. Using your stereo in this situation is damaging your electrical system. You should cease usage of your system until upgrades have been completed.

If your electrical system doesn't react when you power on your amp(s), but the lights dim or something along those lines (In Dodge, the dash LEDs flash) during the particularly heavy bass hits, then a cap can help you out by charging during the down-cycles when your electrical system has some extra energy and providing the needed punch during the heavy hits when your electrical system can't afford the necessary power. However, if this is the situation you find yourself in, you're right on the borderline of what your electrical system can handle and you really should upgrade your alternator anyway. If you're planning on doing a lot of stereo thumping without the car running, you'll also need to upgrade your battery.

If your electrical system seems happy to power your amp(s), but your heaviest hits clip, then a cap may be able to help. If this is your situation, you probably have a reasonably high quality amp. What is happening is that the amp stops drawing power when the electrical system doesn't have it to give. Theoretically, the amp could cut out if the supply voltage drops below 11.5V or so. This idea sacrifices sound quality for the safety of your electrical system. As before, a cap will give you the punch you need for the hard hits so long as it has down-time to charge in between. Again, as before, you're right on the borderline of your electrical system's ability and you really should upgrade your alternator and possibly battery.

If your current electrical system seems happy to power your amp(s) even during the heaviest hits, this is when a cap can do you the most good. Under this condition, even though you probably won't hear the difference, the cap is still taking the brunt of the heavy load bass hits. What this accomplishes is saving your battery and alternator from experiencing the voltage drops caused by the bass hits. This voltage fluxuation is one of the major causes of premature death of your charging system components.

I hope this clears some stuff up. If anyone with a more intimate knowledge of power electronics notices any mistakes or misinformation, feel free to correct me.

Drive Safe