A low-cost high-efficiency DC/DC converter for use in residential fuel cell applications is proposed in this paper. The converter must accept a low voltage, high current input from the fuel cells and convert the power to a high voltage output. This DC/DC converter uses several technologies to achieve the high-efficiency, low-cost goal, including zero-voltage switching, a unique parallel input / series output topology, three interleaved converters, and the ability to turn off a unit during light loads. These technologies combined allow the converter to maintain soft switching over a wider operating range, reduce passive component size, output current ripple, and the necessary transformer turn ratio. The proposed DC/DC converter has been simulated to confirm its design goals and is currently being realized in hardware. Efficiency is expected to be above 96% in the final design. A cost analysis of the proposed design has been performed and the converter meets the low cost goal.