Frequent topping up of 12v Battery

I’ve had 12v battery issues for over a year and my dealer is also puzzled as to why the auxiliary battery needs topping up so frequently.
Two days ago they again replaced the 12v battery (third time) the newest being a more powerful one.
The light inside the front logo and also the ring inside the charge port are showing yellow, and come on at frequent intervals whether the car is plugged in or not.
I fully accept that electronics are at work even after the car has shut down for several hours,
but why do those yellow lights keep coming on and off after being parked for three days without using the car?
Obviously for some reason something is being drained as the high voltage battery is feeding the auxiliary battery (battery saver+ ?). I managed to talk with the mechanic who worked on my car and he had contacted Hyundai for advice, but the electronic readings were within the accepted tolerance recommended by them. They were actually better.
Sorry but I cannot give you those readings without asking the mechanic again what they were.
Have you heard about this problem before? All the software is up-to-date as of the 4th of March.

 

Thanks Mike! That would make sense. I haven’t actually timed it as such but it seemed more frequent than that. Saying that I may go and park the car outside one of my living room windows and keep an eye on it.
It’s about as exiting as watching paint dry. Seriously though, it would put my mind at rest if the BMS has made the change. What would we do without these posts! Thanks again

 

Thanks for the tip KiwiMe. Strangely enough I ordered a similar gadget to the BM2 on Amazon UK in November last year. Unfortunately I've been in Norway ever since and can't go back to pick it up due to travel restrictions. I should have had it sent here
......I briefly shopped around here in Norway but didn’t find anything similar to the BM2. I will try again. Thanks