You know what? ... I'm thinking the same thing ...
This is the third battery in a row I've had fail within a few years. I was thinking heat may be the issue. I knew it was stuffed since our trip up to the Clarence River. The fridge was turning off (when stationary) in the ute ... only the alternator was keeping it running.
I went back to the shop where I bought it from. They put a heavy test load on it (after driving from Lismore to Brisbane) - said it was flat ...
Missus has just got back with Chinese take away ... I'll get back to this later ...