Microsoft has brought out a new feature on My Surface Pro3, when the battery gets to 50% it stops charging, this is so that machines that are constantly plugged in do not damage the battery. It is all here below.
https://www.zdnet.com/article/micro...-charge-cap-aims-to-give-longer-battery-life/
https://www.zdnet.com/article/micro...-charge-cap-aims-to-give-longer-battery-life/