Abstract: A housing assembly adapted to fit into a mortised recess in a door is provided for accommodating components of an electronic lock mechanism. The housing assembly comprises a housing including opposed major side walls at least partially defining an opening into the housing. A circuit board comprising electronic circuitry for operating the lock mechanism is disposed in the housing. A bracket for holding batteries is adapted to be disposed in the opening in the housing. The bracket is accessible when the housing is in the mortised recess of the door such that the bracket is movable relative to the housing between a first position and a second position. In the first position the bracket is in the housing and in the second position the bracket is at least partially outside of the housing such that batteries may be inserted into or removed from the bracket.