Wow!… what battery is in it?
Whatever Chevy put in the original manufacture. I know exactly why the battery lasted so long. It is located all the way back under the trunk base. Normally it is not visible unless I lift the trunk platform which is a large plastic item. It is the heat from the engine which kills batteries.
In my other car, a small Korean made car under Chevy name Spark, I have glued on insulation sheets around the battery which is located near the engine, to help extend battery life.