Battery goes dead too fast

[TLXregnar07]

Recently I’ve been having issues with my truck running down the battery when just sitting. In addition to this I just had this driving issue.
http://www.fordification.com/forum/view ... =3&t=79501
That seems to be over, maybe.
I don’t think it’s related, because the starting issue was already there before this problem. For the last few months, I have had the battery run down while the truck was just sitting, sometimes in just few days. The only key-off battery draw I have is the memory for a radio. I could see the radio running down the battery, but not this fast, since all last year and the year before, the battery would last 2-3 months at least with no issues. At the moment it's more like 2-3 days.
A couple of years ago, I had a very similar issue starting with a dead battery and a burnt fusible link. Posts on that are here:
http://www.fordification.com/forum/view ... =8&t=66084
http://www.fordification.com/forum/view ... =8&t=66152

End point was: installed a new replacement electronic regulator and the problem went away. Is it even believable that a regulator would die that fast? It was a regular AutoZone duralast, is there a more trustable/ reliable brand?
The alternator does appear to charge when the truck is running, at least as good as these old low amp alternators ever did. I’m considering an upgrade alternator, but I want the original right first, so I know the start point for a change.
Electrical issues are extremely hard, I understand, I have traced and tested for voltage, and don’t really find anything obviously wrong under dash or ignition. I know I could just put a battery shut off on it and have to raise the hood before each use, practical yet annoying, but I shouldn’t have to do that, if I can get it right, back to Ford spec.
OK so questions:
Are replacement regulators that junky? Should I try to find an old-style mechanical one, or an actual Motorcraft one?
Could there be short in alternator?
Any other ideas?

[Mach428]

I would do an amperage draw test on the battery with the key off. From everything you've said, either the battery is not holding a charge or there is a draw. You may try disconnecting the positive terminal for several days to see if they battery stays charged.

The clock memory would not draw enough amperage to make the battery die in just a few days.

[TLXregnar07]

After trying to charge battery for 5 hours, and it never got over 11.9 volts, I took the only 18 month old battery back for warranty. Installed new one, started right up, alternator throwing 14 volts. Only had about a 20 milli amp drain, likely the radio.
While working, just to be on safe side, bought the correct Ford ignition coil to replace the Chevy one we had put on in the emergency, when we needed to get it running. They might be that different, but why not make it right?