Master Baron over at XDA-Developers has come up with a very interesting way to prolong your battery life, and has an app build to test his theory.

His theory uses the following logic:

– You can get 2G coverage in all the places that you have 3G coverage

– 3G uses more battery power than 2G

– You don’t “need” 3G data when your screen is off

– Turning off 3G data when your screen is off should save you battery life

The downsides? It’s still pretty beta, and it only works on CyanogenMod 6 ROMs.

If you’d like to try the app, check out this thread at XDA-Developers, which is where you can find the .apk.

If you’re running CM6, let us know how this works for you. Did you get the extended battery life you were hoping for? Any side-effects?