Same thing happened to at least 3 batteries and 2 alternators: this means the problem has nothing to do with either battery or alternator. So unless there is something else in "charging system", there is nothing wrong with the charging system either.

 

Even by your chart (which came from some unknown company that makes "crystal" batteries), voltage limit changes by less than half a volt at all temps above freezing. This isn't enough to make your vehicle not start.

So far you haven't reported any actual problems with your vehicle's performance, so there's nothing to fix here. Hope you learned something.

 

What kind of battery has 2V each cell? This should be learned more than 40 years ago...