In at least one embodiment, a power management module measures an electromagnetic radiation spectrum or a voltage response of a battery module. The measured electromagnetic radiation spectrum or voltage response of the battery is compared to a plurality of reference electromagnetic radiation spectrums or voltage responses, respectively, which may be determined for authentic batteries, for example. A relative condition of the battery, such as an age or state of health, may be estimated based on the measured electromagnetic radiation spectrum or voltage response of the battery module, and stored in a memory store. The rate of change of the relative condition of the battery over a period of time may be determined to identify potential defects in the battery.