Alright guys, help a guy out here!

Couple weeks ago the battery light started coming on...dim at first...then it would go off...then it would come on....then it would go off. I parked her for about a week then went ot start her and nothing...and I mean nothing! So on the charger she went. But the battery light comes on as soon as I start her. And when I pull her back in the garage and put her back on the charger she usually only registers about 50% charge.

I had the alternator replaced about two years ago and I'm hoping I didn't get sold a piece of crap. Anyway, can someone suggest what to check first and how to check it? Would it more than likely be the alternator (checked belt tension and it seems fine), or is there a voltage regulator that might be causing the problem?

Haven't had the ocassion to have her out at night so I haven't checked to see if the lights get dim or not.

Anyway, now that the weather has cooled down up North here I really want to drive her, but can't trust her to sit for too long (or even short). I've got towing and everything, but would rather not have to put myself in the situation where I need to use it.

Any ideas would be helpful. Thanks, in advance, you fine people.

Get your battery charged up and check its in good condition, then get hold of an ammeter. I've just done this test on my 80, which was sucking its own battery dry. Hook up the battery positive lead, then hook up the ammeter with its negative lead to the battery's earth post, and its positive lead to the now disconnected battery earth cable - apologies if you know how to hook up an ammeter, don't mean to insult your intelligence

If its a digital ammeter, with a milliamps and an amps scale, start off with it set on the amps scale, just in case your current draw is more than 1 amp (unlikely, but still you never know!) so you don't blow the internal fuse.
OK, so you should now see the current draw. don't forget to shut the doors/hood so all the lights are off! Keep pullin out fuses until you see a change in the current draw. When you see the current drop, you've isolated the circuit where the draw is. I would expect a stereo with a preset memory feed to draw in the 5-10 milliamps range, so don't be surprised to see a drop in current of about that much when you disconnect the stereo...
Do you have an original power antenna? My juice was being sucked out by leaving the antenna up, so the relay was drawing current - about 0.2 amps infact. Enough to flatten the battery after a few days.
Also, try disconnecting the plugs from the alternator to see if that gets rid of your draw. My alt creates a 3.5 mA draw - I don't know if it's supposed to (I suspect not) but that's not enough to hurt the battery when i'm driving every other day or so...
Anything more than 100mA/0.1A or so should be looked into.
When you've got the dodgy circuit nailed down, let us know...
Good luck!