Need a few Ideas here

[SSEimatt93]

Alright....
So, the Scan gauge in my SSEi tells me at an idle, with the Air Cond running, say at a red light, my charging system is dropping below 10.9-10.8Volts, one I get going again, it migh hit 12-12.5 volts charging. I am taking this as gospel, as at night, the interior lights almost dim to a non visible orange at an idle.

Now, in the morning, say if its colder out (Below 50-55) I have good charge until the car warms up..usually 13.8Volts or so, then by the time I get to work its around 12.9-12.8. This is a fresh Delco Reman 140 Amp (2 months old max) and the Battery is an ACDelco that I purchased from the dealer last August.

I have stripped back and inspected all my cables on both ends, and they look fine, no corrosion or any sort of crap.

We also have a charging system tester at work, I hooked it up, and it reads usually over 14 volts on the top posts of the battery...what gives? Under load test it appears to recover just fine.
Any ideas? There is obviously an issue...as my lights to dim out (WAY more than normal) and the SES comes on PO401 Voltage low..quite a bit..

[2000Silverbullet]

It sounds like you might have a ground issue. Try running a dedicated ground from the battery to the engine. Make sure the alternator wiring to the battery is good. How fresh is the alternator?

[SSEimatt93]

The Alternator is only about 3 months old.

[2000Silverbullet]

My Bird will do that sometimes when it's circuits are loaded and the idle drops....but only after I installed a larger pulley so it turns a little slower thus producing less current at low rpms. It could be the new alternator has a bad regulator. Did it do the same thing before you replaced the alternator?

If it did, then I would suspect a grounding issue.

[lowrider0308]

My dad had a new alternator act up on his truck. It would produce low volts and a battery light after starting up some mornings and then go away. The battery and alternator tested fine. After several tests and a lot of complaining, he got a new alt and everything has been fine. You have a warrenty on the alternator?

[SSEimatt93]

The old Alternator did the same thing, I didn't notice it in the winter, as the cold seems to make it charge a lot better.
I will check the ground.

[SSEimatt93]

Alright, vistiting this yet again...
I changed the Negative battery cable today, new one was only 22 bux..so I Figured..why not.
Still low volts...Alternator is testing around 14.5-14.7 volts charging, Battery is holding a good, strong charge as well.
Why is my Aeroforce still reading low?
The lights dim out and all at night A ALOT as well..if its charging so good, why are my accessories dieing?

The past few days it has been cold and raining outside..Aeroforce has been reading a good steady 13.5+ volts charging, lights have stayed fairly bright.
This morning it was 54 out and raining a bit, started the car, lights were bright, aeroforce said 13.9 volts charging...
As soon as it gets hot out..look out..for it to hold a reading of 12.5-12.9 is a miracle...in traffic at a light..it will dip down to 11.0..this is really bad at night.
I've noticed PO401 only sets a code when its charging good..say over 13.5 volts...why low voltage warning when it says its charging good?
How does the outside climate effect it?

[dpcookson]

Heat and humidity are electricities worst enemies.

Have you checked the harness and connector going into the alternator?

[2000Silverbullet]

How old is the battery? How old is the alt belt and tensioner?

[Jrs3800]

Alright, vistiting this yet again...
I changed the Negative battery cable today, new one was only 22 bux..so I Figured..why not.
Still low volts...Alternator is testing around 14.5-14.7 volts charging, Battery is holding a good, strong charge as well.
Why is my Aeroforce still reading low?
The lights dim out and all at night A ALOT as well..if its charging so good, why are my accessories dieing?

The past few days it has been cold and raining outside..Aeroforce has been reading a good steady 13.5+ volts charging, lights have stayed fairly bright.
This morning it was 54 out and raining a bit, started the car, lights were bright, aeroforce said 13.9 volts charging...
As soon as it gets hot out..look out..for it to hold a reading of 12.5-12.9 is a miracle...in traffic at a light..it will dip down to 11.0..this is really bad at night.
I've noticed PO401 only sets a code when its charging good..say over 13.5 volts...why low voltage warning when it says its charging good?
How does the outside climate effect it?

You make me wonder if you have an issue with the Positive cable from the alternator to the battery... Its a smaller wire than I'd like to see for 125-140 amps... I am wondering if you are having issues with this wire... Possible corrosion internally??

Here is an example... Its a different set up and functions a little different...

On my 95 Trans Sport I had an issue with power and voltage... Would see low volts under load or just out of the blue... Took a while for me to figure out what the deal was... Then one day 12v constant... I knew the Alt was failing so I replaced it... 12v.. I started checking all of the wires and found 14.5v at the alternator and 11.5 at the battery... Knew I had an issue between the Alt and the battery and the gauge was telling the truth... The charging circuit of this van runs from the alternator to the back of the started and from that pole on the starter to the battery.. The size of the wire was half the size of the wire on a Bonneville... And supported a 140 Amp Alt from the factory

In checking these wired I found that not only did it cook the fusible link, it fired the wire at the back of the starter... The wire cooking and failing is the reason I was having issues with voltage... In the end, instead of trying to fix what was there I ran a starter cable from the back of the Alternator straight to the battery in the same manner the bonnevilles were set up.. I know have good voltage all of the time even with a 105 Amp alt and all of the accessories running... I think for me what GM had done was used the 60* V6 W Body electrical system with the 3800 V6, actually a mixture of A body( Cutlass Ciera, Buick Century )and W Body( Grand Prix, Regal ) Electrical parts...

Matt if you could load the system, see what voltage you are getting at the alternator, at the battery post and at the maxifuse positive hub... You are bound to find your issue...

If all tests well you may find a bad alternator... Also have you had the battery Load tested? And what is the Alternator RPM shutoff in your PCM?

[Rusgreim]

Since your charging system tester showed 14 at the battery, I, personally would doubt this has anything to do with battery or alternator.

Is there an AC / voltage connection here? More specifically your fan? Is it drawing a ton of power off the system? What about your cooling fans?

[2000Silverbullet]

Rus may be on to something. If those fans (or one fan) is drawing excessive load due to a failing motor.......

[SSEimatt93]

alright guys, I've got a few things to test now. Easy enough to do. I guess, one thing I could do to factor the fans either in or out would be to drive the car until its hot, with the fans running, remove the Fuse so the fans turn off, and see if that makes a difference.

I need to fix the hole in the Drivers side rear tire first....only holds about 6 hours worth of air..thank god for my Craftsman air compressor!