HTC One M8 - Manual (Page 50)

Checking battery history
Check how long you've been using HTC One since the last charge. You can also see a
chart that shows how long the screen has been on, and how long you've been using
connections like the mobile network or Wi-Fi.
1. Go to Settings, and then tap Power.
2. Tap History.
3. If you've used HTC One for a long time since the last charge, swipe left or right
to scale the graph that details battery usage over time.
You can also slide two fingers together or apart to scale the graph.
Using power saver mode
Power saver mode helps to increase battery life. It reduces the usage of phone
features that drain the battery such as the display and data connection.
1. With two fingers, swipe down from the status bar to open Quick Settings.
2. Tap the Power saver tile to turn power saver mode on or off.
If you want to choose which phone features to conserve power for, tap first
before you turn power saver mode on.
If power saver mode's Data connection option is selected, HTC One automatically
disconnects from the mobile network after 15 minutes when the screen is off and
the data connection is idle (no download activity, streaming, or data usage). It
reconnects and then disconnects periodically when the data connection is idle to
save battery power.
Keep in mind though that the Sleep mode option for the data connection in
Settings > Power, when enabled, overrides power saver mode.
Extreme power saving mode
In times when you don't need to use much of your phone, turn Extreme power saving
mode on to extend battery life longer. In this mode, standby time can last longer than
usual, and you can only use the most basic functions such as phone calls, text
messaging, and email.
1. Go to Settings, and then tap Power.
2. Tap the Extreme power saving mode On/Off switch to turn extreme power
saving mode on or off.
If you want to set when to automatically switch this mode on, tap Extreme
power saving mode and select a battery level.
50 Your first week with your new phone