Access the battery compartment by rotating counterclockwise until collar is removed.
Insert two 9-volt alkaline batteries into the battery terminals. Observe and match the + position towards the inside of the controller.
Remove the cap by pulling outward. Use a flat head screwdriver in one of the side slots to pry if necessary.
Secure the battery compartment by reinstalling the cap and rotating the collar clockwise until tightened.
Test power to the NODE-BT by pressing the battery check button on the front of the controller. Observe and check for the illuminated green LED. If the LED is red, the battery needs a replacement.