High Voltage Engineering has successfully completed the factory tests of a 3 MV Tandetron™ based accelerator system, fulfilling the rigorous requirements of the Facility for Research in Experimental Nuclear Astrophysics, part of the Saha Institute of Nuclear Physics, Kolkata, India. To satisfy requirements, High Voltage Engineering has developed a unique high-current light-ion injector. The injector includes two multicusp ion sources, one for H - and one for He +, and a Na charge exchange canal. Extensive measurements yield routine production of about 70 μA analyzed He − and 1 mA H −. The Tandetron™ designed and tested at 3 kW of beam power features low ripple (27 V RMS at 3 MV), a particle transmission of at least 60% over the entire terminal voltage range, 200 kV up to 3 MV. In addition, the dual slit stabilization system ensures long term terminal voltage stability, ±30 V per hour at 3 MV.