I need help with my ps2 wireless controller I think it just needs new batteries but I'm not sure I just got it

I have a pelican wireless PS2 controller, and I just got it, and I wanted to try it out, but I didn't have any new batteries, so I took the ones out of my TV remote. When I hook the thing that detects the controller in the controller slot, the LED light on it glows green, and the LED light on the controller apidly blinks green when I press a on, so I know it works, but when I try to use it, nothing happens. I mean like it says, "press start", and when I do, it doesn't work. I think it might just be the batteries, but I'm not sure, so can somebody please help me?