Converting energy from one native form to a more “useful” format is usually required to support activities in our daily lives. Our energy reserves come from the sun (direct radiation, interactions with the planet, wind, rain, geo). Energy conversion is fundamental to the processes of life. Decaying radioisotopes from Americium241 (used in all smoke detectors) creates photons in scintillating materials, The photons generate electrical power in a photovoltaic cell. A trickle charge of power lasting decades, from commonly available decaying radioisotopes can be useful in keepalive power for critical electronics (GPS and communications). This capability offers utility in extreme environments (cold and hot), and remote locations (underwater and planetary sensing) for decades (half-life of radioisotopes of interest). What radioisotope, phosphors, and semiconductor materials are of interest? What constraints should we consider using these materials? Where should we look for tapping into the energy around us?