Battery Backup Time And Discharge Process - Toshiba 4300 series Installation And Operation Manual

13.4

Battery Backup Time and Discharge Process

The optional 43TBC battery cabinet provides approximately 7 or more minutes of back-up time depending
on the UPS kVA rating and system load. The exact length of these times will depend on the UPS model
used, condition of the batteries, amount and type of load, temperature and other variables.
Figure 13.1 graphically illustrates the battery discharge process from a full load condition.
Excessive discharge will cause the UPS battery voltage to drop. The chart shown below lists the voltage
level at which each UPS low-voltage alarm will sound and at what level the low-voltage condition will cause
the unit to automatically shut down.
UPS Capacity
Nominal voltage (V
Alarm voltage (V
Shutdown voltage (V
CURRENT VOLTAGE
V
V
V
I
MAX
I
MIN
64
)
nom
)
low
)
min
NOM
LOW
MIN
100%
Battery Capacity
FIGURE 13.1 - TYPICAL BATTERY DISCHARGE CURVE
30 kVA 50 kVA
288 Vdc 288 Vdc
246 Vdc 246 Vdc
230 Vdc 230 Vdc
Shutdown
Voltage
0
20% 0%
4300 Series Installation and Operation Manual
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