Is the bluetooth turned on? That will drain a battery pretty fast. But I don't think even that would go from 3 bars to 2 bars in 2 minutes. I'd take it back.
They're going to tell you to fully drain and fully charge the battery 2 or 3 times, so I'd do that first to see if it helps.
I recently purchased a RAZR V3 Black phone, and about 2 minutes after a full charge, the 3 bars on the battery indicater become 2 bars. Is something wrong with the phone? I don't know what to do.