We all love our iPhones as they are the perfect all-in-one entertainment device. However, if there's one place where we would like to see an improvement, it is in the battery life department. The newer iPhone 4 seems to have a slightly better battery life due to the reworked design, but the older generation wasn't too great like the 3G. Also, if you happened to use Wi-Fi or Edge, you'll find yourself reaching for the charger at the end of the day. I admit it's not easy to put in a large screen and deliver a stellar battery life. It's just like a 15" laptop will never give you the same battery life as a 12" or 13" laptop, no matter how big a acer satellite battery you may throw in it.
But there are certain things you can do to make sure you squeeze that extra bit of charge. Many of the following things are probably already known, but for first-time iPhone users this will come in handy.
Disable 3G and WiFi when not needed
Unless you are using MTNL's 3G service, there is no reason to keep 3G enabled. Navigate to Settings>General>Network>Enable 3G and toggle "OFF". Keeping 3G on will only drain your battery faster. The same goes for Wi-Fi; once you're done using it, ideally turn it off or else it will keep running in the background trying to search for a hotspot and drain your battery quicker. However, unless you have upgraded to iOS4, you can't quickly jump to Settings and toggle it. In that case, there is a Cydia app called SBSettings, which brings a little drop down box from the top that lets you toggle Wi-Fi, Bluetooth, Edge, etc., but you'll need a jailbroken device to do this.
Change your fetch data settings
If you've setup an email account using the iPhone's built-in client, then it's important you change the fetch data settings. Think about it this way, the less your phone needs to access a network, lesser the battery used. Try checking for new mails every hour or better still, set it to manual.
Turn off location-services
This feature is found under Settings>General and is responsible for providing your current position to certain apps that may require it. It is also used for geotagging photographs. It's a good idea to turn it off, as it will unnecessary keep sending your location data and drain the battery faster.
Turn on Auto-Brightness
This feature automatically adjusts the backlight of the screen, so you're not blinded in the dark when you wake your iPhone. The sensor on the front of the phone automatically detects how much ambient light is there and adjusts the brightness accordingly.
Reduce Screen Brightness
While the auto-brightness feature helps, it's not perfect and sometime you may find that even in areas with low ambient light the brightness isn't reduced much. In this case it's a good practice to manually dim the backlight when not needed so that you save battery.
Turn Bluetooth Off
Bluetooth by default is turned off, but when you're not using you're Bluetooth headset with the iPhone, don't forget to turn it off.
Turn Data Push Off
Just like Data Fetch, the iPhone also has built in Push Data for built-in client. Push Data means as soon as you get a new mail, the email server (eg. Microsoft Exchange) will push the mail to your iPhone and alert you. In other email accounts like Yahoo on the iPhone, the phone has to fetch the mail by sending a request to the server to check if there are any new mails. Both of them will drain the battery quickly, as it periodically using the GSM/WiFi network.
If you don't put the iPhone in sleep mode yourself, there is a timer after which the screen turns off. Ideally set it to 1 min, which is the fastest. This way even if you forget to turn off the screen, the backlight will be on for only a minute. dell inspiron laptop battery
Do Less-Battery-Intensive Things
Listening to music doesn't affect the battery as much as say watching a video or playing a game. If you're traveling and know you won't have access to a charger for a long time, avoid playing games like Asphalt 5 or watching a movie. You'll regret it when you need the phone and all you get is that annoying "20% battery remaining" warning message.
If you have any more tips, please feel free to share them in the comments.