Alternator, Battery or Wiring?

[BonesDT]

I'm low on juice. Can't start normally, but can jump start and roll-and-clutch-drop start.

The battery is definitely low, and one would think that would be the problem, but I got a ~1 year old Optima Yellow Top. So I'm thinking the alternator especially since it has never been replaced in 9 years & 150,000+ miles.

Here are some tests I've done so far:
1) 12.77 Volts across the battery with the engine running.
2) 12.1 V for the disconnected battery
3) The engine still idles with the battery disconnected, but actually revs higher when I turn on the headlights. With the hazards, headlights, interior lights, and power windows in full effect, the engine died. Should the alternator be able to handle all of this alone?

The weird thing is that I was able to drive back and forth from work (25 mins each way) today. However, my turn signals didn't work and my speedometer and tachometer were acting crazy. Could this be a wiring problem?

Also, when I was checking things out, I noticed the fan belt tensioner seems crooked at it's pivot point and vibrates a little with the engine running. Could this have anything to do with it. I will try to take a pic.

I saw that commercial where AutoZone was bragging about checking alternators, I'm thinking about bringing it in for that.

What's the best aftermarket alternators?

 

[Tbars4]

...With only 12.77 at your battery while it is charging, I am thinking it is the voltage regulator,(Alt)..It should read about 14 while charging...Pull the alt. to have it checked by itself otherwise, your charging system will probably check out ok at autozone as has happened to so many people..