As I mentioned in some other threads my daughter has a 2021 CX-30 that was bought new in August 2021. She now has 37K and it's running very well. Within a week of buying the vehicle she got a "Battery Low" warning along with a suggestion to start the car and drive it to charge the battery. I put it on a trickle charger but it happened again soon after. I took it back to the dealer who pretty much blew me off by saying to ignore the message. I told my daughter and she has done just that since then (the car has never failed to start). I recently had the car for a week and when I vaccumed the interior the warning came on. I found this thread on the CX-30 forum and it appears Mazda is ignoring this widespred issue rather than fixing it.
https://www.cx30talk.com/threads/battery-discharge-issue-log-of-members-events.1379/
https://www.cx30talk.com/threads/battery-discharge-issue-log-of-members-events.1379/