Liebert Emerson NX UPS System - Manual (Page 52)

Operation
44
5.4 Battery Management—Set During Commissioning
5.4.1 Normal Function
• Constant charging current—Current can be set up to limit charging power.
• Constant boost voltage boost (if applicable)—Voltage of boost charging can be set as required
by the type of battery.
For Valve Regulated Lead Acid (VRLA) batteries, maximum boost charge voltage should not
exceed 2.4V / cell.
• Float Charge—Voltage of float charging can be set as required by the type of battery.
For VRLA, float charge voltage should be between 2.2V to 2.3V.
• Float Charge Temperature Compensation (optional)—A coefficient of temperature compen-
sation can be as required by the type of battery.
• End of discharge protection (EOD)—If the battery voltage is lower than the EOD, the battery
converter will shut down and the battery is isolated to avoid further battery discharge. EOD is
settable from 1.6V to 1.75V per cell (VRLA) or 0.9 to 1.1 V per cell (NiCd).
• Battery Low Warning Time—Settable between 3 and 60 minutes. The default is 5 minutes.
5.4.2 Advanced Functions (Software Settings Performed by the Commissioning Engineer)
Battery Self-Test and Self-Service
At periodic intervals 20% of the rated capacity of the battery will be discharged automatically. The
minimum amount of load must exceed 20% of the nominal rating of the UPS module. If the load is less
than 20%, auto-discharge cannot be executed. The periodic interval can be set from 30 to 360 days.
The periodic testing can also be inhibited.
• Conditions—Battery float charge for at least 5 hours, load 20~100% of rated UPS capacity
• Trigger—Manually through through the command of Battery Maintenance Test in the LCD
panel or automatically
• Battery Self-Test Interval—30-360 days (default setting is 60 days)
5.5 Battery Protection (settings by commissioning engineer)
Battery Undervoltage Pre-warning
The battery undervoltage pre-warning occurs before the end of discharge. After this pre-warning, the
battery should have the capacity for 3 remaining minutes discharging with full load. The time is user
configured from 3 to 60 minutes.
Battery End of Discharging (EOD) Protection
If the battery voltage is lower than the EOD, the battery converter will be shut down. EOD is settable
from 1.6V to 1.75V per VRLA cell (or 1.0 to 1.1V per NiCd cell).
Battery Isolator Open Warning
If the battery isolator is open, this warning will occur.
The external battery to the UPS through an external battery isolator, which is manually closed and
electronically tripped via the UPS control circuits.