How come we have to always deplete the energy of a phone battery or power bank when we first buy it and only then do we charge it?

Question

I’m sorry for the bad english.

In: Engineering

Answer 1

You don’t, and should not do this with lithium ion batteries. NiCd and NiMh batteries may need this to keep the batteries healthy, but not with Lithium-Ion. In fact, it’s best to keep them within 20-80% charge, and not let them fully discharge or charge.