5 Tips To Save Battery Power on an Android

The Android operating system is turning the mobile communications and PDA world on its head by offering features, functionality and an open architecture that threatens to blow away everything else on the market.^[1] However, many of the features available on Android devices can cause batteries to become drained very quickly. Because of this, users of Android devices must intelligently and proactively manage the energy in their batteries. The power-saving options presented here can be used as you wish; all at the same time, individually or in any desired combination.

1. Turn off the wireless feature when not needed. (Settings » Wireless controls » WiFi, or get the Wireless Settings free app) The wireless networking transmitter uses quite a bit of power. Even when the device is not connected to a network, it will continue to search for one on a regular basis. 

2. Turn off the Bluetooth feature when not needed. (Settings » Wireless controls » Bluetooth) For the same reasons as you should turn off WiFi, turn off the Bluetooth feature if you are not using it. 

3. Turn off the GPS. (Settings » Security & location » Enable GPS satellites) When the GPS receiver in your Android device is active it looks for satellites, and its processor prepares information to be sent to any application that needs it, regardless of whether an application that uses the GPS is running or not. If you are not navigating, turn off GPS and let the device use whatever alternative location services your wireless network provider may offer. 

4. Ask your phone what is using the largest percentages of power. (Settings » About phone » Battery use) If you ask Android what's using what percentage of available battery power, it will tell you. The vast majority of the time the biggest power hog is the display.

• Also check Settings-> Applications -> Running Services. Here you'll find a lot of services with their RAM usage on the right hand side. Select such services as "software update", "email" and services not used by you. An option appears highlighted that will say "stop". Select it to end that particular app. This decreases RAM usage and extends the battery life.

5. Tell the device to only use 2G networks. (Settings » Wireless controls » Mobile networks » Use only 2G networks) If you do not need access to high speed data, or there is no 3G or 4G network where you live, you can tell Android to only use 2G mobile networks. You will still have access to EDGE network data and WiFi if needed. 

Source : http://www.wikihow.com/Save-Battery-Power-on-an-Android