Just recently started getting a battery issue. Alternator seems fine. Lights are normal windows move normally etc. Battery literally just got replaced (it is now 3 days old) with audi saying they checked the alternator as well. so here is the problem:

I noticed the car starting rough in the morning again. what I noticed in the evening
With car off parking brake on. Everything would shut off as normal, lights turn off, parking brake light on switch and dash turn off, car is totally black. Then, the parking brake light on dash and button turn on. Then off. Then back on. I notice something under the hood making noise. I turned off the parking brake and lifted the hood and waited. Now, it sounds like the regulator valve is like cycling or something. At least that is where the noise is coming from right above the S/C. I removed the engine cover that covers that area and waited. Sure enough it just makes a click noise and hums for a few seconds then stops. I don't know exactly what is making the noise but it's def coming from this area. It must be using enough power to do this over and over again all night with the car off that in the morning the battery will either struggle to turn the car over, or like my old battery, I'm going to have to hook it up to a trickle charger in the morning.

Audi said they tested my old battery and it kept failing a charge test (that battery was less than a year) so they replaced it for free under the battery warranty (my car has 129,000 miles so that warranty is long gone)

I saw a post someone had a very similar issue in their a5 and the culprit was a bad a/c pressure switch. My ac works just fine. I am going to take it to call audi in the morning to make an appointment but just wondering if you guys had any insight as to what the ACTUAL f is going on.

Car throws no codes, runs smooth as can, no engine mods, all maintenance, has been walnut blasted carbon cleaned, I mean the car has been very well taken care of. For video maybe turn volume up if you cannot hear.