On-line electrochemical impedance spectroscopy implementation for telecommunication power supplies

The batteries in uninterruptable power supplies of telecommunication equipment never run full cycles. Therefore their remaining capacity and state of health is difficult to determine. On-line impedance monitoring could help to monitor the health of the batteries while they are waiting for the next power outage. A cost effective implementation would use already existing components in the system of an uninterruptible power supply. The excitation signal could be generated with the battery charger, the balancing unit, the DC/DC or the DC/AC converter. Depending on the used component, the harmonics of the excitation current changes significantly as well as the components of the converter system which act as a filter for the excitation current Maximum impedance deviations of 1% to a successive measurement were achieved.