If you turn off all the features you don't absolutely need, your phone may run smoother for longer. Let's examine the ways to strip Android down to the barebones so you can eke out that little bit of extra life.
Simplify the home screenThe first place to go when your phone is need of a performance or battery life boost is the wallpaper. If you're running a live wallpaper, turn that off. Depending on the one you're running it could be pulling a few precious milliamps from you battery. You can often tell which live wallpapers are more likely to kill the battery. They're the ones that make the scrolling just a little rough. A static background might be less flashy, but desperate times call for desperate measures.
If you're running a device with an AMOLED or Super AMOLED screen, consider a darker background. Black pixels use no power on these panels. So if you choose an image with a lot of black, you can save battery. If you want to make the biggest impact, keep an all black image around for those times when you really must save all the juice you can.
The next place to look is your widget loadout. If you're accustomed to running a ton of widgets, it might be time to stop. Running a widget keeps the app in active memory and allows it to update. If you drop your widgets when times get tough, you can see some savings.
Tweak wireless settingsWe like speedy data as much as anyone, but if your phone is in the red, that 3G or 4G connection has to go. It's back to the 2G stone ages with you.
On most Android phones you can access this option easily. In the main system settings, find the Wireless & Networks section, then pick Mobile Networks. There will be a box labeled "Use only 2G networks".
Selecting this option will cycle the radio off and on. When it comes back, only 2G networks will work. This is one of the biggest battery savers on Android. Of course, you will pay for it with very slow data. But you will have it if you need it.
If you want to go a step further and really take the definition of phone seriously, you can keep voice enabled, but turn off data completely. HavingAPNdroid from the Market around for this eventuality is a good idea. This app will block your APN settings from connecting, which cuts off data. Voice calls can still get through, but you'll waste no power on data.
Wi-Fi settings are also under Wireless & Networks. If you are not connected to a Wi-Fi AP, you should disable it. Android will occasionally sweep your local area to search for known Wi-Fi access points. This uses a small amount of battery every time.
Take the screen down a notchThat bright, vibrant screen sure is pretty. But when you're in dire straits, it's time to take a trip back to the days when phones had unattractive, dim screens.
First thing, turn off automatic screen brightness. It doesn't really work that well, and uses unnecessary battery. You can do this in the Display menu in main settings.
While you're there, there are two other settings to tweak. When you turn off the automatic brightness, you will get a slider for the manual light level. Crank it all the way down. In the same menu, you will also see screen timeout. The default is usually a minute, but you can turn it down to 15 seconds. That way the screen will shut off if you get distracted, saving power.
If things are getting really tough, check out an app called Screen Filter. We featured it in the Roundup a few weeks back and it can be a big battery saver when you really need it. This app pushes the brightness setting far below the phone's minimum. Just launch it and use the slider to pick a filter level. If you're in a dark space, this might not be so bad, but in lighter settings, the phone is going to be harder to use. These settings make the phone a lot less fun to look at, but we're going for a stripped down experience here.
Background dataWhen it really comes down to it, a lot of your Android phone's battery life comes from the ability to multitask. You can turn this off if it really comes down to it. Head to the main system settings and go to Accounts and Sync. One of the checkboxes here will be labeled Background data. If you disable this, you will get no notifications except for basic system functions like SMS.
You will gain a significant battery boost, but you lose the ability for apps to update in the background and data to sync to your device. Basically, you have yourself a much less enjoyable phone. It's the ultimate in barebones Android.