Long Term Storage
you don’t plan on using your notebook for more than six months, Apple
recommends that you remove and store the battery with a 50% charge. If
you store a battery when it’s fully discharged, it could fall into a
deep discharge state, which renders it incapable of holding any charge.
Conversely, if you store it fully charged for an extended period of
time, the battery may experience some loss of battery capacity, meaning
it will have a shorter life. Be sure to store the ejected battery at
the proper temperature.