DC-UPS systems for larger loads require the use of two 12V batteries to provide adequate backup time and reduce the battery cable size. In order to avoid the limitations of using two batteries in series, the PULS 20A DC-UPS controller individually charges and monitors each battery, and thus maintains the unique single battery concept. During buffering events, a switching regulator converts the battery voltage to a constant output voltage (22.5V, for example). In addition to the same benefits that PULS 10A DC-UPS controllers offer, the one-battery concept of the PULS 20A DC-UPS controller also allows for the output voltage to be set to 22.5V, 24V, 25V, or 26V for applications that require a higher output voltage.