
It all depends on the signal strength. If you are in the area where 3G is good but a weak wifi signal, wifi will use more energy to remain connected. and also, if wifi signal is full and 3G signal is weak, using wifi will yeild better battery life. If both signals are robust, then using wifi will effectively use less energy if you are using your phone actively.If you are a passive user who is not streaming media or chattting or anything...