Apparently the graph for battery power doesn’t scale the same way on desktop as it does on mobile. On mobile the vertical axis is scaled to match the range in the data, on my desktop it doesn’t (tried both firefox and chrome). It’s not a real bug, but sure it is a real difference, and probably one of them wasn’t intended that way.
Thanks for pointing this out @sunny. The website does have a fixed axis for the graph. We will discuss the best approach and make the apps consistent.