Just bought a 2021 CX-30. So far we really like it. My wife uses it mostly. She came yesterday and said that she was getting a warning signal. I went out and it was saying;

"Low Battery Risk. Start vehicle to charge 12v."

I looked in her manual and couldn't find it so got on the computer. (I found the solution on the Mazda 3 Forum) There is a Service Announcement. I've attached it.
I took it out for a 20 minute drive and all is well...
I look forward to enjoying this new vehicle...