> Electrical engineers in 2025 have so many little power drains that any car left undriven for a few months has a dead battery.
Interestingly enough, the quiescent current drain of my 2020s era vehicle is lower than either of my past 2000s era vehicles when I measured it.
The phenomenon of batteries being drained after a few months of being left unattended is not new.
The big issue tends to be complex logic for going to sleep often getting stuck. Ie. "oh, I was trying to use the LTE connection to poll for updates, but the connection got reset so I kept the CPU awake forever whilst retrying every 5 minutes rather than going to sleep mode".
Older cars had this too - I had a bunch of cars which would kill their own batteries if not locked - the engineers assumed that all owners lock the car when walking away, which often isn't the case in your own garage.
It's not, but older cars tried to keep their batteries fully charged. Newer cars with the so-called "smart" alternators never keep the battery full, they always leave some empty capacity to recover energy while moving.