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Chapter 11 Troubleshooting
Reasons for premature battery failure
The forecasted lifespan of the VRLA Battery is typically 3 to 5 years, but this fluctuates greatly
due to the several factors including:
ambient temperature
•
placement
•
maintenance
•
battery chemistry
•
cycling
•
When first installed the battery is at 100 % of the rate capacity; however each discharge and
charge cycle will little by little reduce the capacity of the battery. The depth of discharge
(DOD) will determine by how much a battery's capacity is reduced. The graph shows the
evolution of battery function as number of cycles and depth of discharge for a shallow-cycle
lead acid battery. A deep-cycle lead acid battery should be able to maintain a cycle life of more
than 400 even at DOD of 50 %.
The UPS discharges at a maximum 1.6V
250 to 400 cycles during the useful life of the battery (3-5 years) when using ABM.
Over time, battery capacity degrades due to sulfation of the battery and shedding of active
material. The degradation of battery capacity depends most strongly on the interrelationship
between the following parameters:
the charging/discharging regime which the battery has experienced
•
the Depth of Discharge of the battery over its life
•
its exposure to prolonged periods of low discharge
•
the average temperature of the battery over its lifetime. Frequent discharges can
•
degrade the lifespan
188
of 2.3V
of the battery voltage, so there are btween
PC
PC
6U Rack or Tower UPS RT8kVA and RT11kVA IUOMG
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