Serious Inconsistent Voltage Issue!

[quakerroatmeal 10+ year member]

Well,

As of lately it seems as if I'm having voltage issues. I just got a new alternator, and it still has the same symptoms as the old alternator. Here's the problem, when I first start up the car , reads 14-14.2 with the stock alternator, now when the new alternator its reading 14.5-14.6 at startup. Play some music moderately plays fine voltage is ok. Full tilt of course a lot of voltage dip. Well here's the problem, when I get out and drive the car if I'm driving 45mph+ its fine. A lot of times when I slow down to a stop sign/red light. My voltage would go from 14 to 12.5-12.8 as if the alternator just turned off all the way. It would not raise back up until I start going 45mph or revving it all the way to like 3krpm. At first I thought it was my alternator regulator but the new Iraggi Alternator 200amp came with a new one. I'm just out of ideas if it could be my amp, batteries or what. Batteries when I don't start up the car both reads 12.7-12.8. I already re-checked all the terminal connections, I already did the big3. I'm stressing out I don't know what else to do I'm tired of this crap. Can someone chime in and help me with this ridiculous problem. Sorry its long

Quang

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[audiolife 5,000+ posts]

need a smaller alt pully

 

[audiobahnuser18 5,000+ posts]

this has happened to me before to but my car had a hard time starting sometimes but i found the cause it's my starter don't suprise me it was from 1989 lol .

 

[azbass 5,000+ posts]

Quang's a cool name

 

[quakerroatmeal 10+ year member]

need a smaller alt pully

Iraggi Alternator already put a smaller pulley on there, smaller then stock. Does same thing with both stock and the iraggi alternator, I had to get a shorter belt too for the iraggi.

 

[quakerroatmeal 10+ year member]

this has happened to me before to but my car had a hard time starting sometimes but i found the cause it's my starter don't suprise me it was from 1989 lol .

My car starts fine. Not sure how a starter would mess with the voltage settings though.

The whole setup is

200amp/115a idle Iraggi Alternator

Front stock battery rear Kinetik HC2400

All 1/0, big 3 1/0, 1/0 power.

IA 20.1

18" RE XXX / FI Soft Parts Dual1 @ 0.5ohms

I'm still getting insane amounts of voltage dips at full tilt, would think that the electrical would be up to par with it for a decent amount of time. I'm stressing out someone help me out.

 

[quakerroatmeal 10+ year member]

Somebody...anybody..help me.

 

[audiolife 5,000+ posts]

have you asked irragi?

 

[quakerroatmeal 10+ year member]

He was close by the time I was done. I did email and will be calling him tomorrow. Trying to get some people on the forum to give me some ideas/suggestions on what I can do/test out.

 

[ravendarat 10+ year member]

Whats the draw on the amp? I mean if the alt only does 115 at idle, mabye you quite simply still dont have enough juice? Is this with the lights on, AC running etc? What kinda vehicle is this

 

[quakerroatmeal 10+ year member]

95 Acura Integra. The draw on the amp is probably 250amps or so. No lights/AC on. The thing I am trying to figure out is why is my voltage jumping around, when i'm driving it says 13.8-14.X or so then I'll stop and it'll jump down immediately to 12.5-12.8 (this is without high level volume bumping this is moderately low volume). It will not go up until I reach limits of either 45mph OR 3krpm+ revved.

 

[ravendarat 10+ year member]

Ya man, Im not shocked here at all. Even at low volumes that amp is gonna pull some serious power, you car is probally looking for 60-70 amps already. That leaves you 45-55 amps at idle for the stereo, I would expect that you are pulling more than that with just the amp. What kinda voltage gauge is this. Is it in the dash or part of the amp or what?

 

[quakerroatmeal 10+ year member]

Stinger Digital Voltage Gauge. Maybe around .1 or .2 off from my DMM. I can have the volume all the way to zero, on mute, it doesn't matter the voltage acts weird on its own and its random, sometimes it'll act normal.

 

[spoonraker 10+ year member]

Like somebody else said you just need a smaller pulley. Maybe they put a smaller one on already, but it's obviously not small enough.

Your alternator puts out more or less power depending on the speed it is rotating at. More RPMs on the alternator means more power. The alternator is driven by the engine, via the pulley, and the pulley determines how fast the alternator spins in relation to the engine. A large pulley means the engine must be at high RPM for the alternator to spin at it's optimum RPM. The smaller the pulley, the lower the engine RPMs need to be for the alternator to reach maximum efficiency. Your pulley is obviously spinning your alternator at the correct speed at around 3k RPMs, a smaller pulley will reduce that number to somewhere closer to idle so that you make good power while stopped or driving city speeds.

Remember, most HO alternators were designed for race cars, not cars with monster stereos, so it's no surprise that they are designed to be at maximum power at a high RPM range.

 

[quakerroatmeal 10+ year member]

So I don't get it, there's a smaller pulley on it already. If it needs a smaller pulley, why would it work fine when the car starts up and sits parked? It'll read 14.5-14.6 and recharges perfectly fine, its all when my car starts to drive when it acts up. And sometimes it'll actually work and re-charge normally. I'll check the battery again. Hope dom has some ideas for me when I call him tomorrow.