capacitor, yes? no? dont need?
 

hey peeps i was hoping yall had some knowledge of this. i had a car once with some massive audio, like over 1100 watts just on subs, and another 300 on the mids + highs. it drew so much power it would slow the car on accel, dim the lights, and eventually destroyed the car completely. someone said adding a capacitor would solve the issue / protect the car, but i have no idea and this was some random d-bag. would be greatful to learn the wisdom of this theory if someone is gracious enough to share...:ugh2:

Upgrading the rest of the electrical system would be much more beneficial to you. Replacing your alternator with a high output version and a larger battery plus upgrading your engine wiring. Battery to Alternator, Battery Ground, Engine Ground and Battery to underhood fusebox will also help and/or cure your issue. Capacitors are a band-aid on a broken leg kinda fix. The average cap takes five times as long to charge as it does to discharge therefore, the majority of the time your cap is in the car is spent charging and not helping. They are however good at smoothing out ac ripple from your alternator that makes it past the battery. This ac ripple generally is the cause of hard to find engine noise.

Check out the car audio 101 section for advice about caps.

Also the z's stock alternator can handle a good amount of draw as aposed to older and other cars I have worked on.

If you need a cap DO NOT USE THEM instead it would be time to do, bigger alternator, second battery, "big 3"

rep'd both of ya. and thanks. one thing the car manufacter says is that each car is designed with a battery / altenator for specific tasks in mind that it was engineered to support, but we all know lots of people have successfully modded and had little to complain about. im sceptical about changing major components, mostly because o what happened to this other car i had 10 years ago, which was an epic turd by the way (pontiac grand am lmbo). but i dont plan on getting super beefy bass and all that this time. just gonna replace with a decent HU, some top end door replacements, and maybe one small sub, like 8"?

:iagree:

While a well designed system should never need a big capacitor, it's use is really dependent on the system and should not be frowned upon so readily. If your lights dims only on bass notes, and all is good otherwise, adding a capacitor would help. The cost for one and ease of install is worth a try. The best way to go is always an alternator that is capable of supply the necessary amperage to the system. That said, it is not always practical. Think of the capacitor is a fast filling fast replenish reservoir. Adding one will allow the amps to draw momentary power. It cannot supply sustained power. Your alternator provide that. Because music is transient in nature, power draw often spike, this then come into play when your alternator cannot supply the power but with the capacitor in place, the headroom can be compensated.

i.e.

Alternator supplying constant 70 amps @ idle
Amps requires on transient 65 amps average and 85 amps @ 25 ms

The capacitor would help with the 85 amps spike.

Remember a battery is also a crude capacitor and is another load when it is charging. It has higher capacity and reserve but at a lower discharge rate vs a true Cap. Adding a second battery will increase your reserve listening but also increase your load on the alternator. The bottom line is adding a second battery through an isolator will prevent your system from the draining the main battery, thus allowing you to start your car. It does not appreciatively solve the dimming of your lights.

Think of it this way zakimak, if an amp is pulling X amount of current and making the lights dimming. Adding a cap is only going to take the initial pull from the battery. However a cap does have to recharge, and where does it get that recharge? The battery of course. So your really only applying a band-aid to the situation. Caps actually can have more of a draw on a battery than a amp itself.

When you say "adding a cap is only going to initial pull from the battery", I agree in part if the car is a) not running and b) that the alternator could not supply enough amperage to the system in the first place. Then and only then the the reserve of the battery's power is use to compensate.

The moment that the car is running, the battery becomes a load to the alternator. The battery cease to becoming the source. If the system demands more than the alternator can supply, it will draw from the battery. If continue long enough, the battery will be dead.

By your rationale, the battery is the source of power and if that is the case, an alternator is not needed and your car can run. BTW, a car can run indefinitely without the battery after being started but cannot do so without the alternator. FYI - practically every amplifiers uses capacitor in their output stage, digital ones does it slightly different, but that can be left for another day. All that said is that if you have an amplifier, you already have a fast switching capacitor in your system.

Although the battery, alternator and in part, the capacitor all does essentially the same thing; supply power once charged or rotating. They do it in however in very different ways.

Alternators are designed to supply constant power at certain RPM. Contrary to popular beliefs, the car electronic system is not 12 volts but it is 14.4. That is the charging voltage of the alternator.

Battery are designed to provide a buffer to the system and when the alternator is not in use. aka (starting of the car)

Capacitor in this context is to supply transient power.

Music by definition is not a sine wave where it is constant. If that is the case, a capacitor would be useless. But because music has peaks and valleys, while the load is low, the alternator has already charged the capacitor AND the battery and on on the peaks (dimming of the lights), the capacitor would supply the fast spike past what the alternator is capable of supplying aka dynamic headroom.

There is way too much to get into the specifics but the bottom line in relation to the O.P question, a capacitor would help but has dependencies of other aspect as well. I agree that an high output alternator is the way to go, the addition of a capacitor has it's merit especially in raising the peak capacity of a system which essentially from what I can tell from O.P. is the issue.

I could revert it all the way back to the alternator itself, either way your adding more a a quick draw load on your system with A) a cap b) a amp. Either way you look at it your still putting an additional load on your system the cap as I mentioned is just helping take the initial pull from coming from the battery, but the cap still has to get a recharge from the electrical system.

Bottom line OP a cap will help for a while, however if you do a quick search on google you will find that caps can cause damage overtime to either your battery or your alternator. This is why I do not recommend using them at all.

If you're using a cap in an average system, you've applied a band-aid to a different problem. Like Big said, there's other areas that are cheaper to address and will actually solve the issue and not mask it.

Adding anything into the electrical system will absolutely add additional requirement of the alternator. The difference is that the loads of the capacitor varies in conjunction with the music's demand and is not on the consistent basis. Hence it's merit. It is very logical.

Again given the cost factors and ease of use when comparing to a High output alternator, it is worth investigating when dealing with the dimming issue. All that said, even if you have the best alternator in the world and if your demand is past the capacity of the alternator at transient, then a fast acting capacitor would help. Alternatively, turn down the volume.

As for the reliability issue, in my opinion, there was are several causes. Manufacturers used poorly made ones who jumped on the bandwagon when it was introduced at IASCA back in the early 90s (think it was Wayne Harris and his Octobus) to make a buck, people did not allow enough cooling and not removing bad ones when they bleed.

If evrything thing else, big 3 is done, adding a cap is fine, and should be done, IMO. On a SQ system it will help even out the sound, by providing that lil extra current when needed.
The real problem is people use them in the wrong way and it doesn't fix the problem, yeah cause you didn't use it correctly in the first place!

well the last thing i want is to kill the altenator or battery, or even worse, destroy the car's computer like i did with another car i had. thats why im not gonna get anything big, just want good sounds. im beginning to wonder if im the only person to destroy a vehicle via audio system, since nobody chimed in to share their own similar experience. im hoping i can get away with the alpine IDA X305S and some replacements for the 4 speakers without an amp. but if i add an amp im hoping it wont draw enough juice to necessatate a cap or a new altenator. thanks for all the input, all of you guys are awesome

Capacitors do nothing to help your issue.

The most important upgrade for very high power stereo systems is the alternator. You need a high output alternator, that alone will make a world of difference. With really high power set-ups your drawing more AVERAGE power then your alternator is designed to handle. This ultimately destroys the car like you mentioned.

Others have made good suggestions, your best bet is to upgrade your entire electrical sy stem. High output alternator, a very good battery, maybe two. Also upgrade all your wiring with a larger diameter wire.

I imagine I came pretty close to destroying my first car this way..

I had a 98 accord when I was 16... For some reason in my head I thought it was a good idea to install a 1600w amp that drew over 60 amps :p

I had no idea what I was doing, what ended up happening was my car could not keep up with those electrical power demands. Ultimately my amp blew out very premature as a result, most likely saved the car.