Top-Up Charge - A low rate charge following the main charge, designed to ensure maximum capacity.
Battery cells - The interconnected battery elements that supply electrical power created by electrolytic reaction.
Filter (phase-shift) - Filter used to reduce, if necessary, the overall distortion due to the current harmonics injected into the mains upstream of a UPS by its rectifier-charger. Filtering is superior to that of a traditional filter of the L or C type.
C-Rate (also see Hourly Rate) - Discharge or charge current, in amperes, expressed in multiples of the rated capacity. For example, C/10 discharge current for a battery rated at 1.5 Ah is:
Earthing system TN - Earthing system in which the exposed conductive parts are interconnected and connected to the neutral. The neutral is connected to the earth. The installation must be de-energized immediately in the event of an insulation fault.
Power Sag - Voltage below 80% to 85% of rated RMS voltage for one or more cycles.
Open-Circuit Voltage (OCV) - The difference in potential between the terminals of a cell when the circuit is open (no-load condition).