Dead radio mystery draw observation

My VW has had a slow draw since I bought it in 04. I do not know the source. If I dont run it, somewhere around 2 weeks it will not crank to start due to low battery. I have a smart charger that shows amps xx.x its putting to the battery. I have observed quite a bit over the years as I hit the battery with the charger at least every 1-2 months to make sure it's up and note how low it was if at all.

For about a week I had the dead radio. Pulled the #42 fuse for over a half hour, didnt fix it, disconneted the battery overnight and it came back to life.

The thing is, during that week, I hooked the charger up 2-3 times after an overnight first and then for a few hours in the garage after driving it for more than an hour. I notice the charger was having to put much more than usual back in. I never hooked an ammeter up to see what the draw is, but based on what I saw it was at least 2-3 times larger than my normal 'built in' draw which has lasted many years and in fact likely made my last new battery last only 3 years due to all the voltage cycling. In fact I have considered whether to use a deep cycle next time. Last replacement I put in a battery something on the order of 20-30% larger than the factory size.

I felt the radio, never felt unusual or warm as if it was really on, or some component in it was wasting heat. Anyone every witness this during the dead radio bouts I am sure many of us have witnessed. If you haven't, or didnt know to look, when you get a dead radio, see if you see the mystery draw I did.

Any EEs or electronic familiar with an explanation for this case?

Wondering if the original draw may be related to the radio? While it was dead it had the red led flashing every thirty seconds or so...while good now.the red light flashes ever 2-3 seconds whether the doors are locked or not...been considering changing the radio for something modern with usb etc...only thing wrong seems to be playing possum once in a while...but apparently this draw may be in there...gone pull that fuse and check draws...though I think I did that years ago with no positive results for removing the draw.

You may have a data bus fault. A VCDS scan would help. If devices attached to the bus lose communication (e.g., door lock/window controllers), they can fail to sleep, causing excessive power consumption.

You can also check the voltage drop across each fuse to find the load on each branch while the car is sleeping. You have to manually latch the door with a tool so it can be locked/secured while open to allow all devices to go to sleep and maintain access to the fuse panel.

Refer to charts in this TSB to convert the voltage drop to load depending on fuse rating.

Ill look into it. I do not have Vag-com but it was hooked up last November and twice before that since Ive owned it and the issue has never come up, not positive those who should have been (well known local guru) were looking hard enough.

I think post #3 may apply to me. Sometimes my 10 month old battery drops down to 12.48 volts over night, but not all the time.

Speak of.the devil. A.very.typical voltage after mine sits for 4,5 hours or so after fldriving for at least an hour ...is 12.5 volts plus or minus a tenth..instead I'd what I consider a 'healthy' 12.6-12.8v