We all know, given enough current draw, and insufficient power supply, head lights dim. But does anyone's idle fluctuate with the bass? I have a feeling it's related to the alternator, but just wanted to double check to see if anyone else gets it.

 

The alt produces hardly any current at idle. So the idle goes up when the voltage drops. It's normal, but if it's happening a lot you may want to evaluate your wiring.

 

The wiring should be adequate at 4 gauge from battery to one amp, and another 4 gauge to the other amp. In anything, it's the lack of a capicitor.

Is there any long term damage, or am I placing any increased wear on anything in particular besides the alternator?

 

The only way that I would know if anything is being damaged is if the alternator or regulator died. I don't work with this stuff on a regular basis or have any advances electronics / electrical education.

 

I've had that on all my cars when the the bass hits hard at idle. As far as damaging the alt I did kill one on my old car ('97 Trans Am) so I think it does do something to hurt the alt when you increase the demands beyond its capabilities.

Capacitors can help, but its not the end all solution. The best thing is a high-output alternator. When I had my cap on in the T/A, the lights were still dimming. After speaking with Lightning Audio, they informed me that if my alt cannot produce enough current for the amp then the cap is acting like another battery (ie: drain) on the system and will actually make it worse. Now the alt has to power 2 additional components rather than just one.

Japanese cars are built better than American cars so I'm hoping that this alt will hold out for the duration.

 

absolutely correct.... which is why I'll never recommend a cap to anyone that comes to me for help. yes in some situation it could help, but why pay $100 for a cap (well a bit less maybe), when you can either have your alt. rewound to produce higher amperage, get a new alt., or sometimes just a deep cycle battery will do the trick. The reason your getting the fluctuations, is cause when the alternator runs out of output, the battery covers up for the missing output thats needed. if the battery can't recharge itself fast enough before the next 'big drain' the alternator get strained and in turn drains the battery even more. Eventually the alternator and the battery combined have difficulties supplying the rest of your accessories with power. With a deep cycle battery, you may see a difference. (Please do your own searches on deep cycle batteries and how they work, cause I REALLY don't feel like explaining all that!

 

Sorry, but I started upgrading my vehicles electrical systems in the late 80's. And I disagree about caps. People frequently mis quote Richard Clark as saying that Caps are bad. But RC never said they were bad. Only that improperly installed they are a hindrance. He wouldn't use them if they didn't work. I am sorry about bringing up the most successful person in car audio competition. A cap is a very effective band-aid. Alternators produce all the voltage for electrical devices in cars. Batteries simply start the engine and stabalize voltage. High quality amps use caps to stabalize input voltage. High quality stereo installs use thick copper wire with low oxygen content to deliver power. Because silver or gold wire is too rare/expensive.

 

If you were to play a long sweep, or perhaps a test tone, or even a bass heavy song that has a continuess tone throughout, that cap is only going to hinder the electrical system whether it's properly installed or not.

Anyways, that is a rare occasion, and god help you if you drive around with test tones blaring out of you car! Anyways, I see where your coming from with this, but to me, due to the fact that a cap needs to fully discharge, then must recharge (it does it faster then I can blink, but...) I never really believed in them. I see customers walking in, and their car has 4 1F caps all hooked up in the trunk. In my eyes, that was a waste of money. For that price he could have bought himself a decent HO alternator. Everytime he upgrades his system, whats he gonna do? He's gonna see more dimming, and add another cap? I don't know if you understand what I'm getting at, I may not be explaining myself well enough!

 

I never installed a cap untill they came up with the newer technology high capacity versions. The standard caps try to stay charged even when the stereo is off. I use an alumapro. Fully charges when the stereo is turned on. That's the only time my lights dim. A relay controls the cap and a second relay turns on the rest of the amps/processors. I think I am going to hook up some trunk lighting to the second relay in the next install.

 

I am sorry but this is misinformation. A cap does not need to completely discharge and recharge on every base hit etc. I do agree that a cap is a quick fix (band aid) for the problem and a HO alt is the real answer. However, I think that for most novice installs, it is a good solution and sufficient.

Brett

 

By the time an alternator turns on, your bass hit has been over for several beats of the music. Doesn't matter how big your alt is, or how many volts / amps it puts out. The regulator has to sense the voltage drop before it turns the alt on. By that time it is too late. Caps are nearly instantaneous. The also keep the voltage up at the amp terminals until after the alt has turned on. At that point the cap can start rechargeing while still providing the amps with plenty of current.

 

Caps do exactly what they are designed to do.. They charge up when the voltage on the line is higher than the voltage across the plates of the cap, and they discharge when the voltage on the line is below the plate voltage.
the cap causes much less drain on the system than a battery, and will NOT hurt the alternator. only way it would is if you stuck a huge bank of caps in there completely discharged and tried to connect them at once with the engine running and batter disconnected. otherwise, the battery will take the big hit and the alternator will do what it's designed to do... power the accessories in the car and charge the battery.

caps do benefit systems a great deal, otherwise they wouldn't be used. (I'll agree it's a band-aid, but it's not a hindrance by any means).

That's also why you see huge amounts of them used in ANY audio application, whether it be home or car or professional use. it only takes 5-10000uf in a large home amplifier to smooth the ripple after rectifying the AC into DC, but when you look at decent stuff, it'll have at least 40000uF in it.
I'm getting off the point here, but caps are great in cars and do not drain the electrical system as described above.

And yes, I know what I'm talking about... I'm running a 2500W system in my car on the FACTORY alternator without a problem.
When you really have problems is when you crank the system up and leave it cranked for long periods of time... the only time the alternator is really stressed is when you've got all the accessories running in the car AND have the stereo cranked.. then you'll see a need for a higher output alternator, but it's still not that big of a deal.

also... my car has an ASP underdrive pulley and the alternator still puts out 70A of current at idle.. so I have a hard time believing people who say their alternator doesn't do squat at idle.

 

Thanks Matt!

 

These high output altenators are nearly non-existent in 1/2 Gen Maximas, I know. Serched around for two years before a dealer told me that those altenators will damage electrical systems in the long run, probally sooner. Had to get a normal altenator. As far as the deep cycle batteries, Got a neighbor next door running two high-power amps
(Power Acoustics I beleve) and his dash, parking,and headlights dim when his system is running. He is buying a Cap whe he redesign his trunk this Summer. They wouldn't make them if they wern't nessecary, bro.





By the way, capacitors doesn't fully discharge everytime the bass hits, it is a small draw to compensate for the battery when the cars' engine is shut off.

If anything, Electronics is a stronger hobby of mine....

 

Dammit!!! Someone knows what they are talking about!!!!

 

Yeah.. heaven forbid that happen.. Hell musta froze when Jamie asked me to be a moderator for this forum..