A 20 watt thermophotovoltaic (TPV) battery substitute system is being developed that will provide higher storage capacity and lower weight than the batteries currently used for many military missions. It can also be instantaneous recharged by refueling with propane. The TPV battery substitute incorporates several advanced design features. These include: an evacuated and sealed enclosure for the emitter and photovoltaic (PV) cells to minimize unwanted convection heat transfer from the emitter to the PV cells; a selective tungsten emitter with a well matched gallium antimonide PV cell receiver, spectral control optical filters to recycle non-convertible radiant energy, and a silicon carbide thermal recuperator to recover thermal energy from the exhaust gases. The design of the system and fabrication of the components are discussed.