http://www.techradar.com/news/microsoft-confirms-surface-book-2-battery-drain-problems-while-gaming

The Microsoft Surface Book 2 is a pretty impressive device, but you'll be in for a surprise if you crank its Power Mode slider up to the highest settings while playing games with high system demands.

As it turns out, the battery on the Surface Book 2 will start draining at a rate of roughly 10% per hour if you're playing a game, like Destiny 2, on the highest settings. A Microsoft spokesperson confirmed this in a statement to The Verge.