How does charging a phone beyond 80% decrease the battery’s lifespan?

Question

Samsung and Apple both released new phones this year that let you enable a setting where it prevents you from charging your phone’s battery beyond 80% to improve its lifespan. How does this work?

In: 2724

Answer 1

Higher cell voltage means reduced battery cycle life. Typically the higher % charge you go the higher the voltage gets. 80% is sort of the cutoff threshold where you see diminishing returns in amount charged vs voltage increase.