The battery is 4.5 years old and it is a good model. (They are retailing for over $400 today.

) My main problem is that before I sort of retired I worked from home. The previous batter died largely because I was never driving very much or very far and it didn't get charged on the road enough. I have a decent battery charger and I will throw it on there in the winter periodically to try and offset that.
The mechanic said it was at 56% when he tested it. He threw it on the charger and it stopped charging at 82%, then within minutes dropped down to about 60%. I have no idea what equipment he used to determine those numbers.
It could be that it just went bad (or bad "enough") this week to cause the problem and the previous issues one year and two years ago were unrelated.
I will probably never know. It happened in the middle of 2024 and again in the middle of 2025, then this week. Assuming the problem was not actually the battery I may not find out until next summer.