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.
Battery Saver helps extend battery life, but decreases compute performance. To enable Battery Saver, toggle the option on in the Battery menu.
If your device enters standby mode while on 100% battery, it should last about 5 hours.
Your controller should last about 6 hours of continuous use.
If your controller enters standby mode while on 100% battery, it should last about 9 hours.