Calibrate battery (1) Discharge the battery until the device shut it down, (2) Turn device ON, charge it for 8 hours (or until LED turns green), (3) Unplug and turn it OFF, plug it back in and charge for 1 hour (or until LED turns green), (4) unplug and turn it ON, wait 2 minutes, turn it OFF, plug it back in, and charge for 1 hour (or until LED turns green), (5) unplug it, turn it ON, and use normally. Repeat once a month or so.