Your Magic Leap 2's compute pack should be unplugged from its power source once it has reached 100% charge.
Your compute pack takes approximately 2 hours to charge from 0% to 90% battery and 3 hours to fully charge to 100%. The compute pack's battery can last about 3 and a half hours of continuous use. If you are using a heavier compute application, the battery will last about two hours.
Your controller should last about 6 hours of continuous use.