MacBook Pro battery drain while charging?

[Xscapes]

I have my MacBook plugged to my thunderbolt display magsafe and use it as desktop very often. When I unplug it just now the battery shows only 87%. It usually 97 or 98% when i unplug it when i have it plugged for few days. Anyone else have this problem?

 

[Interstella5555]

It's possible to use more power than can be recharged, so your computer will "lose" power while charging.

 

[GuitarG20]

Yes, if you exceed the wattage supplied by the charger (60W for 13", 85W for 15/17") then you will use all the power supplied by the charger and a little bit out of the battery. This should only happen during heavy system load though.