A battery management system (BMS) must be rigorously tested to ensure all the functionalities and protection circuits are working as intended. In order to ensure the test is standardized and to avoid potential damage to the battery pack as well as the personnel, a device which emulates the working of a battery pack is used instead of an actual battery pack. This paper proposes a multi output flyback device which emulates the cell voltages of the battery pack, the temperature signal indicating battery pack temperature, and the current signal indicating the charging and discharging currents of the battery pack. The user has the added flexibility to control and vary the parameters in order to simulate different conditions such as cell voltage imbalance, over-current, over-discharge, and over-charge to test the protection circuits of the BMS under test.