Batteries - Emerson Liebert NXL series Operation And Maintenance Manual

Liebert NXL UPS
3.4.2

Batteries

Although the individual battery cells are sealed (valve-regulated) and require only minimal
maintenance, the rack mounted batteries should be given a periodic inspection and
electrical check. Checks should be performed at least annually to ensure years of trouble-
free service.
Voltage Records: With the battery DC circuit breaker closed and the connected UPS
operating, measure and record battery float voltage. With the DC circuit breaker open,
measure and record the nominal (open circuit) voltage. Both these measurements should be
made across the final positive and negative terminal lugs. Compare these values with those
shown below. The recorded nominal voltage should be no less than the value shown; while
the recorded float voltage should be within the range shown. If a discrepancy is found,
contact Liebert Services.
Table 2 Battery voltage, nominal and float
UPS (kVA) Number of
Cells@400V
250-300-400 198
800 240
Power Connections: Check for corrosion and connection integrity. Visually inspect wiring
for discolored or cracked insulation. Clean and/or retighten as required. Refer to torque
specifications in the Installation Manual.
Battery Cell Terminals: Check for discoloration, corrosion and connection integrity.
Clean and tighten if necessary. Note that when installing a new battery, the initial torque
value is higher than the re-torque value.
Rack-Mounted Batteries
If the UPS system uses a rack mounted batteries perform maintenance on the battery as
recommended in the battery manufacturer's maintenance manual, available on the
manufacturer's Web site.
Page 63
Operation and Maintenance Manual
Battery Voltage, VDC
Nominal
396
480
250-300-400-800kVA
Float
446
540