Just curious, not that the activity level is a good thing, but why run on battery while docked?
Laziness maybe?
I wrote, "dock etc" as I don't use a real dock, I have a 7-port USB-hub for network, keyboard, mouse, extra display etc so the battery is only charging when I also plug in the power. Having seen the excessive SSD wear by the DisplayLink driver, I removed the 29" LCD from the USB-hub and now plug in an HDMI adapter to the Display Port. That means three cables to plug in. Think "Big Picture" when I write stuff.
Sometimes I can't be bothered with the wriggling the stupid power connector into place if I am only going to be online for ten minutes, so I leave it to the battery to power the thing. Otherwise, I usually only plug it in to charge overnight. If I am going to be on the SP2 for hours - and in the office then of course I plug it in. I have several power supplise around the house for other times too.
It is a pity that msoft didn't get that connector right until the SP3. That little blade makes all the difference.