I have a relatively new (<1yr.) Dell Inspiron 15 laptop, which stays plugged in all the time. It's connected to a flatscreen monitor via HDMI & I keep the lid shut, so that screen's off.
Yesterday I noticed after I shut it down that the 'charging' LED was lit after shutdown, so I turned it back on to see why. The battery was at 98% charge & said it would be 5 minutes before fully charged.
While I was using it throughout the day, it was doing a 'full' antivirus scan, & I was watching Netflix. Nothing draining really.
I don't understand how the battery could have been draining while it was plugged in. Can anybody offer an explanation?