Due to the high-power density, high torque rating, low torque ripples and fault-tolerant capability, the Dual Three-Phase Permanent Magnet Synchronous Motor (DTP-PMSM) has recently emerged as a feasible alternative for automotive applications. However, it comes with its own challenge of increased losses at low torque due to the use of 6-phase inverter or two three-phase inverters. The DTP-PMSM drive model can be designed to function in two operating modes, double-channel (dual three-phase) mode with both the inverters operating, and single-channel (three-phase) with one of the two inverters shut down. This paper proposed an efficiency analysis between single channel and double channel modes in a DTP-PMSM drive. A simulation model is prepared to calculate efficiency, and the losses associated with different parts of battery fed DTP-PMSM drive system operated in both modes. Detailed loss model is simulated to represent efficiency of a battery-fed DTP-PMSM drive system. Both single-channel and double-channel operating modes are assessed in terms of system and component efficiency, switching and conduction losses, and current ripple. Efficiency maps that cover torque-speed plane are generated to show a clear boundary on the efficiency performance of single and double channel operations. It is demonstrated that at lower torque, the efficiency of the system under single channel mode is up to 3.31% superior to the double channel mode.