Battery Life

• The iPhone 4S contains a rechargeable lithium-ion battery, similar to the models before it. Lithium batteries provide a long life in a light package, because lithium is the lightest metal. At full charge, the iPhone's battery lasts up to 200 hours on standby, but only 10 hours for video playback, 40 hours for audio playback, six hours for 3G Internet use and eight hours for 3G talk time.
  
  

Charging

• Like all batteries in Apple products, the 4S's battery is designed to charge rapidly at first and more slowly toward the end. It takes the iPhone's battery only about two hours to charge most of the way, to roughly 80 percent, but it takes another two hours to charge fully. The battery can be charged via a USB docking cable through a computer or a wall outlet with a power adapter.
  
  

Reset and Restore

• When the battery meter is stuck, the problem often goes away after a reset. To do this, press and hold the sleep/wake and home buttons until the Apple logo appears. If this doesn't work, update your iTunes software, iPhone software and apps, which may solve the problem. For example, at one point, the iPhone encountered a charging bug, and Apple released a fix with a software update. As a last resort, restore your iPhone to factory settings to reinstall the operating system. Connect your iPhone to your computer. Open iTunes, and click your iPhone's name on the left under Devices. Click "Restore" in the center of the screen. Follow the prompts in the dialog box to complete the process. Because this is a display problem, it shouldn't involve the iPhone's actual hardware, but if no troubleshooting options work, take your iPhone to an Apple specialist who can examine the internal parts for damage.
  
  

Battery Care

• To keep your battery in optimal condition and prolong its life, use your iPhone regularly. This keeps the ions inside moving, which is important for keeping the battery working properly. Apple suggests going through at least one full charge cycle, from 100 percent to zero percent, at least once a month. In addition, turn off unnecessary features such as location services, push notifications; data fetching, such as automatic checks for new emails; Bluetooth and Wi-Fi. Dimming the screen, turning off the equalizer, shutting off 3G and locking your iPhone can also keep your battery lasting longer. Open the Settings app to access and change these settings.