A harmonic radar system for detecting a battery may include a signal generator for generating one or more transmit radio frequency (RF) signals, one or more low-pass filters for removing harmonics from the transmit RF signals, a transmitting antenna for sending the transmit RF signals into an environment, a receiving antenna for receiving signals reflected or re-radiated by the battery in the environment in response to the transmit RF signals, one or more high-pass filters for filtering the received signals, and a spectrum analyzer for identifying a harmonic frequency of the transmit RF signals in the filtered signals.