Liebert 1000kVA - Manual (Page 59)

Operation
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Battery Rating (Modules Only): This setting is a battery discharge rating in kilowatts under par-
tial load for an extended period, typically 60 minutes. The UPS uses the two battery shutdown voltage
settings and the two battery discharge ratings in computing rated and calculated time remaining dur-
ing a discharge event.
Battery Float Voltage
Both the information entered here and the actual float setting in the hardware are determined based
on the battery’s requirements. This information is generally available before factory testing and is set
up at the factory. If the information is not available, it is set to the default of 540VDC.
Temperature Limit Setting (Optional)
This setting is visible when the optional battery-temperature-compensated charging board is
installed. This setting determines the battery temperature that triggers the Battery Overtemp alarm.
The alarm becomes active when the temperature setting is exceeded for more than one minute.
NOTE
The Low Battery alarm setting is designed to be useful at full load battery discharge rates. It is
typically set for 10 volts above the 60-minute Battery Shutdown voltage, to provide some
measure of warning under all circumstances. If the discharge period extends past 15 minutes
(i. e., the load on the UPS is less than full capacity), the Battery Shutdown voltage setting is
gradually and automatically increased to protect the batteries from deep discharge. The Low
Battery alarm setting is not automatically increased and should not be relied upon as an
accurate indicator of battery time remaining. Instead, the operator should consult the Battery
Time screen or Present Status screen to see the calculated time remaining based on actual
usage during the discharge period.