I just learned something. Even though my MacBook says my battery is at 84% (battery app says it's at 84% at 9% Capacity), as soon as I unplug it to run down the hall to use the printer, it shuts down. So actually next to no battery life at all. Thankfully, it still works with adapter.
Eight-four percent of nine percent capacity means that you are at eight percent of a new battery. And despite marketing claims to the contrary, those numbers are at best a guestimate, based on arguable data, it is entirely probable your battery is incapable of supporting more than "low power" operation. I would urge you to bite the bullet and send your MacBook to Apple for battery replacement as it is possible that, if the battery fails completely, it is possible that it will not run
even with the charger plugged in.
