Nissan Repair: BATTERY LIGHT, electrical inspection, battery cable

Question
I JUST PUT IN A NEW ALTERNATOR AND BATTERY IN MY CAR JUST RECENTLY THE BATTERY LIGHT AND BRAKE LIGHT CAME ON, ALSO MY CAR SEEMS TO BE SLOWING SO WHAT COULD BE DRAINING MY BATTERY IF I JUST REPALCED THE ALTERNATOR?

Answer
I would think the master fuse at the positive battery cable is blown or the new alternator is defective.  I would charge the battery and go to Autozone or Checker, with the car, and ahve them perform a free electrical inspection to let you know if the car is charging properly.