I recently bought an Acer Aspire 5 series laptop but have been encountering some strange battery issue. Although the battery is reducing at a fine speed, but the battery remaining time indicator is kind of a joke. It goes from 5 hrs to 1 hr 40 min and back to 3h 35 min in a second when i change the power saving options. For example, chosing battery saving mode actually reduced the remaining time from 4 hr something to 1 h 38min and like so on. Is it a drivers issue?