The battery of my iPad 1 WiFi used to last about 10 hours. I just bought an iPad 2 WiFi + 3 G and it's battery last 6 hours. I do not have a SIM card in it. Is it normal for the iPad 2 battery to last only 6 hours? Is there anything I can do to improve the situation? Do the GPS and the 3G (with no SIM) functions decrease battery life?