As gtalk is an app that will do more than when it is not running and signed in, I expect battery time to drop.
That disable internet is a new thing to me. Did you mean you disabled WiFi? If so, that's a power consumer in cell phones. It's like turning on the air conditioning in a car. You'll get less miles per gallon.
I have samsung ace duos s6802 mobile which is dual sim mobile.The battery draining fast when I use gtalk signed in always.My battery stand by comes good when i disable internet what may be problem?