Battery and Rectifier Provisioning for Near-Constant Loads

This paper outlines a method for determining required battery and rectifier capacities in central offices. Constant and nearly constant office loads are considered, representative of digital switching and transmission systems. The battery capacity is computed from the full-load current, the required reserve time, the depth of discharge, the end-of-life capacity, and an allowance for converter loads. The rectifier capacity is then determined to supply the load current and recharge the selected battery in a specified time. It is shown how the rectifier capacity may be selected to ensure a recharge time of 40 hours from full discharge, in the presence of one failed rectifier.