possible electrical/charging problem

[perna00]

ok, here's the sinerio. i have a 96 cav. 2.4 convert. my car idles rough. i've got the garbage jet module that gives me a digital readout. i notice that the reading will fluctuate along with all of the voltage in my car when ever any accessory is used (especailly the stereo, i can see the voltage drop when the bass hits). i've got 2 amps. one an alpine one a kicker zr 360 which uses alot of voltage. i've got a spiral dry cell battery and i 1 farrad cap. i have replaced the alternator about a year ago and added a 4 gauge wire from the alt. to the battery. i've also added 2 more grounds from the battery to the engine and chassis. my car still idles rough. i can actually make it drop power by turning on my wipers or even hitting my breaks. if i have my stereo on loud at night it actually dims my light to almost nothing (and pissed off all neighbors with-in a mile) and if i have the car floored from about 6k-6.5k the battery light comes on telling me that there is not enough amps coming out of the alternator. somehow i'm not getting enough amps. i do have an underdrive crank pulley which i know cuts back the amps produced. i think i'm going to have to get a larger alternator. i know summit offers one that produces 90@idle-150@highway. any one know of something else it could be or is the replacement alternator probably needed? if it is, will that be a strong enough alternator.
*i'm planning on getting pics of my car so i'll post them soon

[Three_Fingers]

Sounds like yer making a slower-on-purpose turning alternator do double the work.
I'll bet your alternator's voltage regulator glows in the dark.
That's where the failure prolly is.
Heat is killling it most likely-heat from the excessive load.

I was you I'd get a heavier alternator/regulator and put a bigger diameter pulley on that alternator so IT will spin at stock speeds even though you got an underdrive pulley on the crank.
Calculate the maximum current load you'll be pulling through it and go some over that when picking out an alternator.
You can't expect the alt to 'idle' and provide maximum output.

[perna00]

k, where can i get a slightly larger pulley? aren't they mostly all the same size? i know i'll still need a larger alternator. any chance anyone knows where i can get one even larger than 90-150? think that i'll increase horsepower with a larger alternator cause of my lack of voltage i'm running now?

[twiztid420]

what kind of wattage are u running? Cause 1 farad cap is only good for 1000 watts

In my 87 hatch i ran 2 1000 watt amps a crossover all hooked to a 1 farad cap and i kill my altenator

So luckly it was under warranty and got a new so now i have 2 batteries
1 deep cycle which goes to the 15 farad cap which the 4000 watt rms amp runs from and its pretty hard to kill the voltage now

[perna00]

i probably got about 850 watts rms through the system. last times i tried using 2 separate batteries i went through alternators again and again. you got the deep cell all by itself or is it connected with the front one? i know they also have those isolation boxes to only let voltage flow one way, those help somehow? either way i'm probably going to need the higher output alternator?

[twiztid420]

yes the deep cylce is connesct to the front battery

[perna00]

i just found a buy on ebay that rebuilds alternators with higher amps. i talked to him for a while and he's going to send me one with a 20% smaller pulley to compensate for my underdrive pulley and puts out a max of 180 amps. hopefully it works, if not it looks like i'm getting a deep cycle battery too.

[Three_Fingers]

Ah, I was talkin' out my ass back there in that post...I MEANT smaller alternator pulley. Shoulda said so then, shouldn't I have?

Well, you got the idea to make the alt turn faster.
Voltage has nothing to do with horsepower.
You need a certain voltage to fire the plugs, but after a point, it doesn't matter and ya'd not notice a difference unless the voltage at the plugs was too low to start with.

If you wanna figure loads:
WATTS=VOLTS x AMPS (Basic equation)
AMPS=WATTS divided by VOLTS (What you'll be pulling thru that alternator).
Voltage is pretty much a constant. Give or take a couple.

Your cap on your system doesn't care what your alternator output is as long as you don't exceed the cap's voltage rating. (It'll 'pop' and spew very hot oil out one end if you exceed the voltage rating).

Deep cycle battery couldn't hurt, but ya really don't need it.
All a deep cycle is for is severe, extreme discharge/recharge cycles. It tends not to develop the 'memory' that standard batteries do.

[perna00]

i understand that voltage and horsepower and not related, but i think it will make a difference cause i notice that the more accessories i have on, the worst my car idles. i even tested quite a few 0-60 runs and noticed that just having the lights on takes away .2 secs off my time. it's a wonder i haven't fried this alternator yet. been using it about a year and a half so far.