I had upgraded to ubuntu 12.04 from Ubuntu 11.10 and I am also using gnome classic. But the Battery indicator is Missing in the taskbar. So i followed the link (http://askubuntu.com/questions/78979/battery-indicator-missing) found here..
I had used the same command mentioned here. But the Battery Icon was not visible.. I am using dell laptop with intel pentium.
rgds, Biju