Hybrid power systems that combine fossil fuel generators with an electrical microgrid are more efficient and practical for automotive, naval, and aviation industries. This paper demonstrates an electro-thermal battery emulator to aid during design and initial testing phases of electrified systems. A 2.4 kWh battery pack is represented using an equivalent‑circuit model coupled to a lumped thermal model with heat generation. Deployed on a hardware-in-the-loop setup, emulation is performed through a bidirectional power supply and liquid cooling system. The electro-thermal battery emulator’s ability to emulate modeled pack-level responses is demonstrated by two case studies. Root mean square error (RMSE) is used to quantify the magnitude, and the time assurance criterion (TRAC) is used to gauge shape similarity between emulated and modeled responses. Case study one investigates emulation of a battery pack under a driving cycle load profile. In case study one, the emulator achieves RMSE values 46.7mV with a TRAC score of 0.9963 for electrical emulation. Thermal emulation achieved an RMSE of 0.359W with a TRAC score of 0.8850. Case study two demonstrates a 1C discharge, comparing a damaged battery pack (loss of two parallel strings) and a healthy battery. In case two, electrical emulation resulted in an RMSE of 14.1 and 17.9mV with TRAC scores of 0.9998 and 0.9998 for the healthy and damaged packs, respectively. Thermal emulation achieved RMSE values of 0.155 and 0.167W with TRAC scores of 0.9979 and 0.9936 for the healthy and damaged packs. Demonstrating the emulator's accuracy in both electrical and thermal emulation.