Does anybody know where to purchase a hi-output alternater for a 2.2 balt from??? My sounds drop the volts down to 13 volts. They used to be about 14 volts. Now I gotta put a trickle charger on the battery at night to fully charge it. You guys think the battery is dying out or the alternator??? It starts up ok...and no dummy lights on the dash. But it seem like my ignition is'nt running up to par. Should I replace the delco battery with more cca???

 

You shouldn't need to put a trickle charger on it at night. The battery voltage itself is ~12.7 Volts, so even if the alt. output is dropping into the low 13's it's still charging the battery.

What's causing the lights to dim is the voltage drop. Every time a bass note hits it draws more amperes from the battery. When that happens, voltage has to stay the same, but since the internal regulator in the alt. can't switch that fast, the lights dim.

That's why some systems benefit from a capacitor. They help eliminate the voltage drop. If you're exceeding the output of the alt. at the time of the voltage drop, then there's nothing to fix that except a better alt. Even a capacitor won't fix that. Neither will a higher CCA battery.

The easiest analogy I've heard used is water.

Voltage is the water pressure.
Amperes is the rate of flow.
Resistance is how far a flow valve is open.

Think of the battery as a pressure tank which holds 12.7 PSI. Think of the alt. as a water pump. It's job is to keep the pressure up to at least 12.7 PSI, plus supply all the things in the car with pressure to help them run. The easiest way for it to do that is have it put out 14.4 PSI.

The amp needs, let's say 20 amps to play constant music (we'll call that gallons per hour, or GPH), plus the headlights need 20 GPH and the alt. can only put out 80 GPH at 14.4 PSI. Well, you're already at half what the alt. can put out.

Now, all of a sudden a bass note hits and the amp needs 60 GPH to do so. It sucks the all the pressure from the battery by emptying the water line (the wire to the amp) of water, and the alt suddenly has to up the flow to 100 GPH to both fill the battery and feed the amp and the headlights at the same time. The sudden need for flow drops the output pressure of the alt. to 13.3 PSI. Since the amp keeps sucking the pipe dry, and the alternator is trying to keep it supplied with enough flow, the pressure drop causes a lack of flow of water to the headlights. They're now only getting 13.3 PSI and maybe only 15 GPH of flow. That's why they dim.

Adding an additional pressure tank, be it a battery or a capacitor, will help keep the flow up momentarily, but eventually the alt. has to "refill" both pressure tanks. Either can help the problem, and the capacitor will be quicker at it than a battery, but it changes the demand on the alt. from instant, high pressure drops, to more gradual, lower pressure drops. But the life of the alt. will decrease and it will not last as long.

Adding a higher output alt. will increase GPH to, let's say 120 GPH. It won't have to work as hard to keep the flow of water going to the battery, the amp and the headlights, and everything will get enough PSI and GPH to work properly. It's a better long term fix.

I hope this simplifies it a little so you can better understand what happens when the headlights dim. This analogy doesn't take into consideration the fact the alt. only puts out 80 amperes (or GPH) when the engine is at 1,500-2,000 RPM or higher. At 500 to 1,500 RPM the "flow" may be as low as 60 amperes (or GPH).

 

nice way to explain it... +rep

 

Thanks for the reply. I guess no one knows a hi-output replacement for our cars. I need at least a 140amps to keep my battery charged. Is anyone else having voltage drop problems??? I'm only pushing about 500 watts with the amp pushing a 2 ohm load.

 

Weak sauce, my voltage used to drop into the tens during idle and hard hits.

 

hell no mine burly got to 11.9 and i was runnign probably twice the power as you hack.... but ya lat time i checked no one makes a cobalt alternator yet... did you hit up all the main places or what?

 

You don't need an upgraded alternator for 500watts. A 1 farad cap should help regulate your voltage levels and keep them above 14V while the car is running. My system is 2000watts (~1100watts RMS) and I have a 2 farad cap. My voltage holds steady in the mid to high 13V range. I haven't had any problems with a dead battery. You probably already know this, but don't run your stereo unless the car is running, otherwise you will drain your battery pretty quickly. Where are you reading the voltage levels? If you're getting your reading at the amp, you may need to use heavier gauge power and ground wires. What are you using now? If your system is 500watts, you could benefit from a 1 farad cap. If your only using 8 gauge wire from your battery to your amp, upgrade to 4 gauge and you'll be able to flow more current, therefore keeping your voltage levels higher and more consistent. You shouldn't need to bother changing the power wire from your alternator to your amp, the stock wire is pretty beefy (~4 gauge).

 

ya a small cap should help you out... a 1v loss isnt really anything to be worried about

 

You only need a 1/2 farad for every 500 watts. The more the better though. Also when you ran your ground wire did you run an extra ground from the battery and ground them off at the same place in your trunk? I was told that this will help you out a lot and with your amp you shouldn't need a capacitor or anything else to keep your car running like it was from the factory.

 

adding an extra ground from the battery to wherever youramp is grounded isnt nessicary... and for a good portion of the amp installs in the cobalt the amp is close enough to the battery that that is going to be your best ground.

 

as far as a bigger alt... you can have it rebuilt to a higher spec.... costs a lot, but it can be done...

 

but for a 1v loss messing with the alt is a waste

 

no doubt, but, i was just answering the man's question

 

damn.. i would have to buy a 2 farad cap then? im pushing 1800 RMS with 2 10's..

 

could do a 2nd battery as well...

 

Evidently, I, once again, feel as though I've wasted my time.

Why do people come here asking questions then refuse to listen to the correct answers? They only do what they want to hear people tell them to do even if it's incorrect.

I guess I'll join in on the fun....

You need 5 batteries, a 10 farad capacitor and blue neon lights under your car for it to work.

There. Is that what you wanted to hear?

 

straight up... thats the only way it works... what i want to know is how you found out. weve been trying to keep that a hush hush secret for forever

 

See...i just asked a simple question...and it turns into a pissing match! I know about current draw and emf. I know what my problem is, I need more current and maybe a second battery. Also I might upgrade the stock delco battery. I might just see if a local alternator shop can beef mine up a little bit. Also remember that a drained electrical system will have your ignition running rough at times. Thanks for da replies.

 

I didn't mean for it to turn into a pissing contest. My apologies.

The only reason you will need an extra battery is if you're planning on running the system while the car is off. Even then, you'll need a battery isolator. It will keep the car's battery charged while you drain the battery going to the system and it will keep one battery from draining the other.

In order to gain maximum benefits of an extra battery, the head unit, crossovers, parametric equalizers, etc. should also be run off the spare batter.

A capacitor does help a system react quicker to short, instantaneous bursts of music, primarily kick drums (think of Metallica - One). It has a quicker discharge time than a battery does as well as the rectifier in an alternator.

It will not cure an inefficient charging system. It will only be an addition to the strain put on the alternator. It's just one more thing the alt. has to "fill".

LOL

Thought you could keep it from me, didn't you.

 

IMO rewinding the stock alt isnt a good idea... you will gain a bit in terms of top end but you will probably loose alot of your idle power. That alone will make you end up using trickle chargers every night. See if you can get a SS/SC alt (although the belt sizes are different so check up on that) if anything.... I got a 200a alt and like most of them it makes maybe 1a at idle so using one alone isnt going to help a stop and go type daily driver

 

Really. I hadn't heard that. Why?

 

well think about it gm didnt make the alt with tons of extra space in it so usually rewinding it creates a lil harsher enviroment for evertyhing inside and kills your idle power. Im honestly not sure why but the higher total output power u get kills the bottom end. Anyway im lookign at the "birthsheet" on my alt and from 1800-2k its making zero power and from there it bows up to ~200 at 4200 rmp and ends at ~ 235 at 6k. But since this is an addon to my current alt that doesnt really matter because only thing that happens is the voltage on the system is going to drop and the battery will have to kick in but for what its worth its going to be alot better then it is now

 

Ahhh.

I know my wife's '99 Olds Intrigue suffers from an overheated rectifier because GM made the alt. too small (in size).

Cruising down the road in OD at about 40 mph the headlights dim in and out. Put it down into third gear and it'll stop because of the increase in RPMs.

I would guess that's similar to what you're referring to and experiencing. Is there any way to put a smaller pulley on yours? That would cause it to spin faster which would, both, put out higher amperage at lower engine RPM and help keep it cooler.

On the flip side, it would reduce HP output on the engine though. If you're a HP junkie that may be a problem.

 

i may or may not get a power pulley for the alt

 

sorry to bring an old thread back but cant you just replace the rectifier with a higher output one?