Low voltage on datalogger, faint glowing from CE, brake, radiator cluster lights

[Dan2]

My car has been doing some weird stuff lately, maybe this is related. I'm really thinking this is a battery or alternator, and thought someone might know for sure:

1) My datalogger is showing 12.3v battery voltage upon initial startup. As I drive around it creeps to around 13.5-13.6 peak. Then after it idles for a long time it seems to drop back down to 12.5 or so. Turning on the radio, A/C, lights, etc. all affect the voltage.
2) While driving around, especially after just starting the car up, I noticed the Check engine, Radiator, and Brake lights on the gauge cluster would very faintly glow. They weren't ON, but just barely emitting light. If I pulled the ebrake up a tiny bit, it would seem WAY brighter.

Any help's appreciated. Thanks.

 

[Defiant]

Your alternator has died.

 

[trbotaln]

same thing happened to me and it was an alternator fuse

 

[Thunderskull]

Your alternator has died.

Happened to me and it was the alternator. I've had an alternator fuse blow, and that is different. Your voltage will never go much beyond 12 and then will start to drop plus other wierdness. Your problem is a dead alternator.

 

[Blue92]

Alternator, car should run at 13.8 V with a good one.

 

[Dan2]

Man o man...
My alternator must've been going out for ages. I put in a new one today ($135! ) and the voltage was at 14.1-14.2v on the datalogger. SWEETTT... my headlights are astoundingly bright compared to before, the glowing dash lights are gone, the fuel pump doesn't make awful sounds when the turn signals are on, and the car runs INCREDIBLY hard. I am not joking, the car is significantly quicker with a new alternator. I guess 12.2v really does take a toll on performance.