I've got two things going on and I'm guessing they're related.
I was coming home after dark and nailed a skunk about a quarter mile from home. I hate it when that happens. I left the car outside in spite of pouring rain because I didn't want the whole garage smelling of skunk.
The next day when I went to start the car I noticed two things:
1. The starter turned slower than normal, as if the battery were not at a full charge.
2. The rear spoiler lifted immediately before I even moved the car.
The next day the battery was low enough that the starter wouldn't even activate. I put a charger on it. Once fully charged I checked the battery voltage a couple of times with a multi-meter and observed that it indeed was dropping. Inside the car the small warning light on the spoiler switch on the console was illuminated. So for now I've simply disconnected the battery. But I've got to figure this out. What's up with that spoiler lift system and why is it pulling from the battery? Any ideas?

 

You are describing a bad battery. If you want to know what is draining it, remove the ground cable, insert an ammeter, and measure the current flow. Wait three minutes after connecting the meter to get an accurate measurement. You must see less than .06 amp (60milliamps), any higher value indicates a problem. You must wait 3 minutes, as currrent flow will be high at first, until modules hibernate.

It is possible you had water instrusion and your CLP/SSM is now wet and destroyed, draining the battery, but in a Coupe I really doubt that.
Also, it is possible water backed up in the windshield drain, flooded the blower for the climate control, and that resistor/regulator is flowing current - but again, after ONE night, I doubt this.

I suppose hitting the skunk could have caused damage under the car to the alternator, but I really can't see that happening.

In any event, you don't diagnose current flow by observing battery voltage, you do so by measuring the current. PLease see the attached, this comes up so often, I took the time to write a document addressing this very issue.

 

OOPS. Uploaded wrong file - it's fixed now.

 

Pizzaguy,
Sincere thanks for your lesson and guidance. I'll have to retrieve my clip leads from the trunk of my Hudson tomorrow before I try the ammeter testing process. The way this battery is responding to charging, I'm beginning to wonder if the battery itself is the problem. It's only about two months old. A brand new ACDelco. I would think that if I fully charged the battery it would start the car again. That's not happening.

 

The battery shop in Cincinnati swapped the current battery for a brand-new one. I put the new battery in and conducted your "Battery Drain" test. It went exactly as you described. Initially it showed a current just short of 0.3 amps. After settling into hibernation, the current jumped between 0.01 and 0.02 amps. So, I guess that's normal, right?
That red light is still illuminated in a solid fashion on the spoiler override button on the console. Is that normal?

 

It is lower than average which is good. Mine runs just below .02 amp.

No it is not.

I"d start the engine and measure battery voltage right across the battery (make sure you change the leads to the right jacks first).
The battery voltage should be 13.80-14.20 with the engine idling and up to 14.4 at 2000 rpm.

 

So this is now a one day old battery. First of all, it DOES start the car! That's an improvement over the other one.
At idle I'm getting roughly 14.55 volts. At 2000rpm it goes up to roughly 14.65.
I've been removing the negative cable at days end to eliminate the draw from that ongoing red light.
As the previous battery was failing, the spoiler was raising as soon as I started the car. That's NOT happening now. I've not had it out anywhere with the new battery in place to get up above 60mph to make sure the spoiler goes up on its own.