Emerson 250-400kVA Manuel D’Utilisation

Because individual battery characteristics are not identical and may change over time, the UPS mod-

ule is equipped with circuitry to equalize battery cell voltages. This circuit increases charging voltage 

to maintain flooded type battery cells at full capacity.

Although the individual battery cells are sealed (valve-regulated) and require only minimal mainte-

nance, the Battery Cabinets 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 Cabinet DC circuit breaker closed and the connected UPS oper-

ating, 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.

Power Connections: Check for corrosion and connection integrity. Visually inspect wiring for dis-

colored or cracked insulation. Clean and/or retighten as required. Refer to torque specifications in 

Table 4.
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 5 lb.-in. more 

than the retorque value. Table 8 shows battery retorque values.

If you have a different model battery, contact Liebert Services for the required torque value.
To access battery cell terminals, disconnect the inter-tier cable and two shelf retaining screws. Once 

disconnected, insulate (with protective boot or electrical tape) the cables to prevent accidental shorts. 

The battery shelf can now be pulled out. Tighten each terminal connection to the retorque value. 

When replacing a battery, the terminal connections must be cleaned and tightened. Disconnect and 

insulate the cables connected to the battery. Secure each battery shelf with retaining screws when 

maintenance is complete.

Risk of electric shock, explosive reaction, hazardous chemicals and fire. Can cause equipment 

damage, personal injury and death.
Do not use equalize charging with valve-regulated, lead-acid batteries. Refer to the battery 

manufacturer’s manual, available on the manufacturer’s Web site, for specific information 

about equalize charging.

240

480

527 - 552

C&D batteries

 UPS12-300MR

110 in-lb

 UPS12-350MR

110 in-lb

 UPS12-400MR

110 in-lb

 UPS12-490MR

110 in-lb

 UPS12-540MR

110 in-lb

Enersys

HX205-FR

65 in-lb

HX300-FR

65 in-lb

HX330-FR

65 in-lb

HX400-FR

65 in-lb

HX500-FR

65 in-lb