Not sure why, but thats assuming that the battery life extender option setting does actually exist on your laptop, in either windows configuration settings or the laptop startup BIOS and it is showing as disabled.
Worth checking to see if it exists in 'enabled' state and set it to 'disabled'.
One thought, if the setting is in the startup BIOS and you haven't changed anything recently, it may be worth keeping a check on the Clock/Time settings in the BIOS each time you power-on to see if that changes randomly. If so, likely culprit is a failing CMOS battery that maintains the BIOS settings memory.