With your help, I think I have figured this mystery out. Since the charging system seemed to be working and the battery was adding power after being driven, I was forced to decide that something was draining the battery over time. With one battery cable disconnected, I checked the draw on the battery. I then reconnected the battery and checked the draw on at the fuse box, one fuse at a time. Going through the fuse panel one by one to check current, I found that fuse #8 was accounting for virtually all of the current flow shown at the battery. The clock is on that and it was indeed working but really could not account for much power usage. The over head light is there and when turned on, the power jumped. So that wasn't it. I then opened the glove box. The light was on but there was no jump in power. When I pressed the light switch in there the power dropped to almost nil. I released the switch and the power jumped. I closed the box and it stayed the same. I then saw that the strap from some item that my wife keeps clogging her glovebox with was actually hanging out and could be keeping the door from closing enough to actuate the switch even the the door was latched. I removed this item and now the power drops when the door closes. After sitting overnight in the cold, the car now starts up as usual. Thanks to all!

You can take the car to your favorite store; i.e.Autozone Advanceauto and they will load test your battery for free.

Yes, it sounds as though the charging system is working.
The wire in question, if it goes to the sending unit next to the alt., which is in fact the oil sending unit, would not be causing a battery drain.
The battery should be checked out and only after it has been fully charged will you get accurate test results.
Dirty or loose battery terminal connections can cause intermittent charging problems keeping a good battery from getting a good charge from the alternator.
Check the battery.
Check the connections (clean and tighten them just for piece of mind,don't go by looks alone).
Check tension on alt. belt.
Check to make sure that the crank pulley is not slipping, this can be done by chalking a line across the inner and outer parts of the balancer/crank pulley and then seeing if they still line up after it has run and been revved a few times.
If all above check out to be in good working order and the problem persists,then it is time to try to figure out what is draining the system.

Do the electric door locks work? A friend's 86 240 had an overnight battery drain problem that turned out to be worn wiring in the driver's door for the central locking system. Unplugged the wiring to the driver's door lock and the problem stopped (but he had no electric door locks). Worth a look.