When I use the SP3 as a tablet and pen and do some illustrations and presentation for about 30 minutes, I notice that my power went from 100% to about 20% every time. It was shocking. A fully charged SP3 cannot do 2 thirty minute presentations on a single charge. FYI, I use One Note for business illustrations I use the Microsoft Photos App to show some photos Thats it....from 90% plus or sometimes 100% to 20% plus. Anyone any ideas? In fact the battery issues is one of the reasons why I don't use my SP3 as my primary tablet. At 40-50% brightness, all I get most of the time is 3-4 hours of usage before the battery goes flat.