Supercapacitors are used in many applications where high reliability and long life are important. In the Richardson RFPD Supercapacitor Guide, applications are grouped into three basic types—power backup, cycling, and pulse power. Certainly, any given application can be a combination of one or more of these basic types, and the considerations to properly determine supercapacitor requirements vary based on these basic types. Determining the requirements always starts with “How much power (or current) for how long, over what voltage range?”

This paper will focus on the steps to calculate the supercapacitor requirements for simple power backup, as this basic type is the most straightforward. For the purposes of this paper, simple power backup is defined as a slow-charge, voltage-maintained supercapacitor bank used to provide backup power due to a power disruption. Typically, this power requirement would be short term—a minute or less.