According to the Auto Zone desk clerk, my battery is fully charged ("100%") But yesterday the starter's dragging during cranks became slower and slower--until it won't turn over at all.

Probably too simple for some of you avatars, but not so the case for me.

Any clues for me?

Joseph

 

You need to be sure the alternator is charging when running. Auto zone can check that for you if you can get it running. Second, can you use jumper cables from another car to jump start it? If it is still slow to crank, but does start could be timming too far advanced.

 

Could also be a bad starter or corroded battery cables at either end. You can check the alternator with a volt meter if you have one. You should get 14 volts at the battery with the engine running.