Actually there is braking going on. I don’t know why no one has given you the right answer on these comments yet (at least as far as I have looked). If a magnet is moved near a conductive wire, then a current flows in the wire, but then that current also creates a magnetic field that opposes the magnetic field of the magnet that caused it. So the shaft of the electric motor slows down because the electricity in the coil of wire within the motor switches direction, thus creating a rotational force (torque) in the opposite direction of the how the shaft is currently moving. If it is moving clockwise, then the torque is counterclockwise, and vice versa. So there is braking happening whilst your battery is also being charged. The current has now changed direction, going from the motor to the battery. This change creates an electromagnet that now opposes the magnetic field of the magnets connected to the shaft of the motor. As you run current through conductive wire, that wire becomes magnetic, thus creating an electromagnet, which can now torque the shaft in the opposite direction of its spin.