Using the new iPad plugged into the charger, the battery capacity still decreases. Started with a charge of 87%, charger plugged in, browsed for about 2 hours (mainly news blogs & sites), the played Sudoku for about an hour and a half. Charge was down to 37%. Recharged for about five hours and only reached 87%. Really going to need a higher capacity charger.
Out and about for three hours, cellular data turned off, used WiFi for about 5 minutes, used iBooks for about an hour and a half, charge down to 55%. Seems the display is the primary need for the larger battery and not 4G.
Maybe 'Y' splitter USB cable plugged into a dual 10 watt charger would help the charging time, power requirement?