Open Power Options by clicking the Start button, clicking Control Panel, clicking System and Security, and then clicking Power Options.
On the Select a power plan page, next to the plan you want to change, click Change plan settings.
On the Change settings for the plan page, click Change advanced power settings.
On the Advanced settings tab, expand Battery, expand Low battery level, Reserve battery level, and Critical battery level. Change the percentage of battery remaining that you want for each level, and then click OK.
Usually answered in minutes!