5 lines, 625 B
Battery use notes the charge about once a minute while the device is awake, together with what it did: screen refreshes and pages turned. From that it works out how much an hour awake and 100 pages take, and how long the battery lasts at that pace.
Open Battery from the Tools menu. It shows the charge now, this time awake, the use on battery so far and your recent times awake. It pages with the page buttons, or by tapping the arrows at the top.
It needs a while of reading on battery before the figures mean anything. Recording is on by default and can be switched off in Settings, under System, as Record battery use.
