The status bar shows how much battery you have left, but you can also see the exact percentage and approximate time of battery life remaining. Swipe down from the top of the screen, then touch 
Battery.
Your battery is built to get you through your day. When you’re running low, Marshall London’s battery saver conserves your battery power so you can still make calls and send SMS (text) messages. To turn it on, go on to 
Settings > Battery > Battery Saver