Surgical light backup power should be checked where the supply ends and its function begins: at the illuminated surgical field. This article explains how to define the supply chain, distinguish installation requirements from equipment specifications and review compatibility before replacing a luminaire.
It compares the documented features of ETK EPU-H and ETK EPU-L units and sets out criteria for linking transfer, runtime, controls and light output. It also explains how to investigate discrepancies without automatically blaming the battery and what information the acceptance record should retain. The aim is to provide useful evidence for hospital engineering, maintenance and clinical engineering teams, tied to the configuration actually tested, with clear records of its operating conditions, results, responsibilities and any remaining limitations.