Emerson 250-400kVA manual Matching Battery Cabinets-Optional, Battery voltage, nominal and float

Maintenance

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.

! WARNING

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.

Matching Battery Cabinets—Optional

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.

Table 2 Battery voltage, nominal and float

	Battery Voltage, VDC
Number of Cells
	Nominal	Float
240	480	527 - 552

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.

Table 3	Battery retorque values
Battery		Battery Model	Retorque
Manufacturer		Number	Value
		UPS12-300MR	110 in-lb
		UPS12-350MR	110 in-lb
C&D batteries
		UPS12-400MR	110 in-lb
		UPS12-490MR	110 in-lb
		UPS12-540MR	110 in-lb
		HX205-FR	65 in-lb
		HX300-FR	65 in-lb
Enersys
		HX330-FR	65 in-lb
		HX400-FR	65 in-lb
		HX500-FR	65 in-lb

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.

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