To address ultra-low frequency DC-DC converters, we explore the concept of the switched battery converter. It is mainly derived from the switched capacitor converter topology replacing the flying capacitors by flying batteries. The best-inclass energy density of batteries compared to inductors and capacitors reduces drastically the operating frequency at low output power delivery while maintaining low output ripple. An experimental evaluation using mm 3-scale off-the-shelf NiMH battery is described in this paper to present a first proof-ofconcept of switched-battery converter. The characterized 2:1 DC-DC converter achieves 25mW at 1.2V output voltage in 74mm3 battery operating as low as 0.1Hz operating frequency while maintaining less than 15% output voltage ripple without output filtering.