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TOSHIBA
24
Operating the UPS
Battery Recharging
The illustration below shows a graphical representation of the UPS battery recharge process
after a full discharge.
The recharge process usually consists of three periods. During the first period, the current is
maintained at approximately 1 ampere. This current limit is the maximum value that can be
used to charge the batteries (for minimal recharge time) while assuring safety and long battery
life. In the second period, constant-voltage control starts and current gradually decreases as
the batteries charge to their normal fully charged state. In the third period, a slight "trickle"
current continues to flow into the batteries to keep them fully charged and "floating" at the
normal Vdc level. A full recharge usually requires 24 hours (90% recharge in 12 hours) after
a complete discharge.
The following chart shows the rated maximum and minimum battery voltages and the charge current for
each of the sizes.
Rated Battery Voltages
Model Vmax Vmin Icharge
3.6kVA 245.7 170 1.0 amp
6kVA 245.7 170 1.0 amp
8kVA 327 227 1.0 amp
10kVA 327 227 1.0 amp
14kVA 327 227 1.0 amp
18kVA 327 227 1.0 amp
Fully
Charged
0
0
Current
V
oltage
Charging
Current
Battery
Charge
Vo
l
tage
Vmax
Vmin
Discharge
Shut-off Point
Time
Period 1
Period 2
Period 3
Icharge