Supercapacitors are adopted as energy storage solutions in a variety of power management applications due to their intrinsic physical characteristics that provide advantages over traditional batteries. In automotive applications such as start-stop systems with regenerative braking, supercapacitors can provide the energy needed to engage the starter to restart the combustion engine as well as accept the kinetic energy recovered during braking. This paper addresses the challenges related to charging these large capacitors, and shows power system designers how to evaluate and select the best system configuration for backup energy storage. A supercapacitor charger solution is demonstrated, with waveforms and detailed interpretations presented.