Android phones, apps and tablets

Going back to power management my iPhone comes off the charger at approx 07.15 am, then will have exhausted it's charge by approx 16.00 and will need to go back onto charge until 17.00 or it will be dead before I get home.
So with Wi-Fi and so forth in use (but no GPS) it has a run time of around 10 hours before it turns itself off and will not turn on again until recharged.

Can you turn 3G off on an iClone? It will save you muchos powerlos.
I find 2G fine for the most part and only 3G it when I'm going to browse or download for more than a minute or two.