A few quick q's and then I'm afraid I can't help much more:
- Are you sure that is the discharge port? There is a separate second port for charging?
- Did you or can you check with a multimeter that the voltage (is it 36V or 48V?) is actually being delivered to those brown and blue wires you mentioned? If you don't have a multimeter, you really should get one - they cost as little as $10.
- The controller is rated for the same voltage as the battery (36V or 48v)?
- All the other connections have been made? controller to motor, hall sensors, throttle?