battery drains in 7 hours while parked

92 buick lesabre, got last summer 120,000 kms have had problems with cam sensor code and wet weather, probably bad conection somewhere
, also water getting inside, think i fixed that OK.
Anyways..its been minus 20 celius and snowing.Car has been starting no problem all winter.this morning all I got was starter solenoid clicking,
gave it a boost and started right up,let run for a while restarted no problem,tryed after a few hours and got clicking again. I had just replaced the alternator(bearings went) about 3 weeks pryor, so figured battery going south, got new battery and after charging a while it started no problem, let run for about 1/2 hour charge indicator dropped from 17 to above 13 so figured it was drawing less charge and battery was good. left for about 6-7 hours and it didnt have enough charge to unlock the doors. question could bad relay be the short problem, possibly trunk light or something on, snow between the solenoid contacts?I suppose it could be 1 of a thousand wires. does the alternator guage reflect battery voltage or just how much charge going to it, any similar problems or clues?? anyone want to buy a lesabre

Not sure of your whole problem, but why not try a quick and easy test. Take the battery into a Canadian tire (I assume your Canadian because you said celsius) and get them to test the battery. Entirely possible your new battery is a stinker.

At least this will rule out the battery being the problem. Or put the battery in another vehicle and see if the problem persists.

I discovered that the trunk wasn't quite closed all the way, maybe this is what is draining battery, but got in the car this morning and heard clicking and such noises coming from under dash, where the computer is, maybe just trying to turn on the things that are programmed to happen when the doors are opened(lights etc) but has me a little worried, think I will throw in the old charged up battery, clean positive post and try again hopefully I wont fry up everything