I shut down my brand-new laptop last night when the battery was around 80%. It was unplugged, and I expected it to remain powered off, but this morning it had only 5% remaining. What could cause that much battery drain overnight?
4 Answers
The exact shutdown method matters. Closing the lid, pressing the power button, choosing Shut down, and installing updates before shutting down can all behave differently. If it happens again after a confirmed full shutdown, check battery health and consider contacting the manufacturer, since the laptop is new.
Check the power settings and BIOS. Disable USB power while the laptop is off, enable the deepest available power-saving or ErP setting, and review wake-event settings. Also make sure closing the lid is set to shut down or hibernate instead of sleep if that is how you normally put it away.
It may not have fully shut down. Windows can leave some systems in a low-power sleep state, especially with Modern Standby or Fast Startup enabled. The laptop may also have woken itself to install updates and then remained active for hours.
Try holding Shift while selecting Shut down once, then see whether the battery still drains. You can also turn off Fast Startup and disable hibernation if you want Windows to perform a more complete shutdown. Checking the Windows update history may confirm whether updates ran overnight.
It turned out the laptop woke up around 3 a.m. and downloaded and installed a large batch of Windows updates, so it apparently was not completely powered off.