JuiceDefender – Squeeze More Battery Life Out of Your Android Device [1.6+]( Best android Application)

JuiceDefender for Android says the answer is yes.
Before we begin, one note. The link above leads to JuiceDefender’s beta version. LaterDroid, the developer, normally offers a free version on the Android Market. However, at the moment they’re having some trouble with the market, and have asked me to link to the Beta version instead. It’s free and quite stable.
When I started the app, the first thing I noticed was the unique look-and-feel of the interface:


Many say Android’s lack of UI guidelines is bad, but this is one app that uses its creative freedom to good effect. The interface blends copious amounts of explanations along with the buttons, in a way that feels natural and uncluttered. As you can see above, it starts off disabled by default, so tap that “enabled” button to get started.
What JuiceDefender essentially does is disable some of your device’s functions at times you’re not likely to notice, thus saving you some precious power. For instance, if you’re not connected to a WiFi network, JuiceDefender will simply disable your device’s WiFi radio. Once fifteen minutes elapse, JuiceDefender will enable the radio again, check for a connection, and if there’s still no connection, it will shut it off again. So you no longer have to remember to toggle WiFi off when you leave the house or the office.