Apple Pencil Won’t Pair

If you have not used the Apple Pencil in years, I'm guessing that you haven't charged it either. With as small a battery as the Apple Pencil has, my guess is the battery has failed. You can have it checked, however the only resolution would be to purchase a new Pencil. You cannot replace the battery in the Apple Pencil.

The teeny tiny Lion battery in an Apple Pencil will simply fail if uncharged for an extended period of time. And that appears what your situation is. You'll undoubtedly need to purchase a new pencil and when you do, remember you cannot leave the pencil uncharged. Used or not, the battery needs to maintain a charge.

Thank you for that. You will still need to contact Apple Support about the Pencil. I still believe the battery has/is failing given you had not charged it for an extended period of time.

You mention a 6th Gen iPad, so I'm guessing you have a 1st Generation Pencil. According to your initial post, you were never able to pair the device, so I'm not sure what you are referring to when you said that it briefly worked yesterday. What do you mean how could a battery fail if it's at zero. Zero charge means there is minimal battery. It may have been an anomaly that it connected briefly, but I would get the device checked by Apple to determine what it is.