A leadless pacemaker (LP) is configured to be implanted in or on a cardiac chamber. The LP includes a first housing made of an electrically conductive material, a second housing made of an electrically conductive material, and an inter-housing insulator between the first and second housings and electrically isolating the first and second housings from one another. Electronic circuitry within the first housing includes pulse generator(s), sense amplifier(s), and a controller. A battery within the second housing provides power to the electronic circuitry via conductors that electrically couple poles of the battery to the electronic circuitry within the first housing. The LP includes two or more electrodes including at least one tip electrode and at least one ring electrode. At least two of the electrodes are selectively couplable to a pulse generator to enable delivery of pacing pulses to the cardiac chamber in or on which the LP is implanted.