No, I have not run it with lights on to see if it drains out. We live out in the sticks, so I would have to either idle it carry a spare battery or such. Mostly, just have not tried it.
While I do not know if the problem has been solved, it certainly could not hurt and avoids future problems. It might be as simple as a weak alternator and upon looking seriously doubt they actually put on a "rebuilt" alternator at all on the road when my wife broke down. To dirty for a rebuilt and that was only about a month ago and a 1,000 miles. Probably just billed $400 for wiping the old one off with a shop rag.
(Middle aged woman driving an out of state old Porsche knowing nothing about cars - easy target, no? As the problem only surfaced with the lights on, having it done in the AM would mean she would be 500 miles away before this known. This might be the story, but not sure. It is certain it did not need another alternator.)

There is no doubt the alarm drains the battery while parked and the alarm is a mess (compounded by a previous owner adding a second alarm and we literallty could not drive it due to the alarm system ignoring the S-key. I began unplug one thing and then another until the lights stopped flashing and it would start - however I will hear the flasher switch clicking for a minute or so any time the door is opened...

Hopefully, I will figure out how to completely remove or fully disable the original security system (if possible) and the second aftermarket alarm system completely.

While maybe unwise in the city, these are sleepy little towns with few road between them and a lot of small town police, sheriff's deputies and troopers all about. Our 928s are parked at our bedroom window and at night they are loud enough to wake the dead. While in the city police will yawn at a stolen car call, here they would throw up roadblocks for the whole area and probably turn on the air raid sirens (which they do 3-5 times a day as it is) as it would be the big crime of the month. Not much happens for them other than lots and lots of speed traps for tickets. So scratching the S-key would be low risk.

Do you want the fenderless 84? If not, I'd lreally ike to give him a call. Also, if you want to go out of the loop on any topic, my email is dfwx@hotmail.com.
Thanks again.
Mark

Buss Replacement
 

My 85 928 had enormous electrical problem that I chased for over a year. It was finally resolved by replacing the brass fuse base plate buss. It had a crack in it that would separate when warm, so the car started fine and then crapped out when it warmed up.

Just a thought when chasing 928 electrical problems.

bill in ca