Simon’s Blog

Depending on what you are doing on your iPhone and what features you disable, your iPhone can last anywhere from 4 to 150 hours.  The following is a list of what drains the battery most, in order of power drain.

• Recording Video
• LCD brightness
• 3D graphics, gaming
• 3G
• GPS
• WiFi
• Bluetooth
• Push

Recommendations for Max Battery Life

If you have a 3GS enable the battery percentage meter, you will gain a better sense of what activities drain your battery (Settings -> General -> Usage). Don’t go overboard on recording boring videos nobody will watch, you can see the battery percentage ticking away while shooting video (the processor is working hard to compress the video on the fly).  Set your brightness to about 1/4, it’s bright enough and auto-brighness will kick in when you are under bright lights and sunlight.  Don’t play 3D games if you need your battery life.  Disabling 3G will give you a huge boost in battery life, I would say the phone lasts at least five times as long if not more, you can always enable it briefly to do some surfing or download email attachments.  If you find yourself down to 10% battery life, disable 3G and you can make it another couple hours.  Disable location services in the settings app, or avoid GPS apps like Google Maps and the Camera app.  Always use WiFi instead of 3G when you can, but disable WiFi and use Edge for maximum battery life if you are only making calls and texting.  Disable Bluetooth unless you need it.  Disable Push email, push notifications, fetch mail less frequently from less email accounts.

Other tips

• disable iPod equalizer as this utilizes the processor
• set screen auto-lock to 1 minute to minimize LCD usage
• turn on airplane mode in low or no coverage areas so that the phone isn’t constantly trying to establish a cellular connection
• completely deplete the battery once a month to maintain battery health
• update to the latest software, 3.0.1 as of August 2009

Disabling all these features makes having an iPhone kind of useless, if you keep the brighness at a moderate level it’s very hard to deplete the battery in one day, unless you talk on the phone for hours or play 3D games.  If you are super hardcore consider replacing the internal battery with a higher capacity model.