Charge your Apple lithium-ion battery whenever you want. There’s no need to let it discharge 100 per cent before recharging. Apple lithium-ion batteries work in charge cycles. You complete one charge cycle when you’ve used (discharged) an amount that represents 100 per cent of your battery’s capacity — but not necessarily all from one charge. For instance, you might use 75 per cent of your battery’s capacity one day, then recharge it fully overnight. If you use 25 per cent the next day, you will have discharged a total of 100 per cent, and the two days will add up to one charge cycle. It could take several days to complete a cycle. The capacity of any type of battery will diminish after a certain amount of recharging. With lithium-ion batteries, the capacity diminishes slightly with each complete charge cycle. Apple lithium-ion batteries are designed to retain 80% of their original capacity for a high number of charge cycles, which varies depending on the product.
One charge cycle is completed after you’ve discharged 100 per cent of your battery’s capacity.