the light is a small LED. it has such a seriously low power draw, you could run that light alone for months and not drain the battery. What will drain the battery is sleep mode, depending on if you are using hibernation, just how deep sleep is set for etc. There's only 2 states possible, On or Off. Sleep is still on, just doing very little, but still does things. This is draining your battery far faster than a blinking LED. Also to consider is both heat and battery age. Hotter the battery, faster it drains, older the battery, less charge it'll hold, faster it seems to drain.