2 “You Need to Fully Deplete Your Battery Before Charging”
The idea that you should completely drain your battery before recharging it actually applies to older nickel-cadmium and nickel-metal hydride batteries, which have fallen into disuse.
On the other hand, lithium-ion batteries, which are ubiquitous in consumer electronics, actually last the longest when you recharge them and keep them at between 40 and 80 percent. In fact, if you keep lithium-ion batteries at zero for too long, you run the risk of seriously damaging them. Another way to prolong your lithium-ion battery’s life is to keep it in cool temperatures.