Toshiba 4200FA CT/XT - Manual (Page 42)

TOSHIBA
6.7 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 steps. During the first step, the charging
current is maintained at approximately 4.0 amperes for the 15/25/30 kVA with internal
batteries, 10.0 amperes for the 15/25/30 kVA with internal transformer and approximately
11.5 amperes for all 50 kVA models. This current 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 step, constant-voltage control starts and current gradually decreases as
the batteries charge to their normal fully charged state. In the third step, a slight "trickle"
current continues to flow into the batteries to keep them fully charged and "floating" at the
normal DC Voltage level. A full recharge usually requires approximately 24-72 hours (90%
recharge in 10 X discharge time) after a complete discharge.
The following chart shows the rated maximum and minimum battery voltages, and the
charge current for each of the sizes while the unit is maintained in a 75 °F (24 °C) ambient.
Rated Battery Voltages
15/25/30 kVA 50kVA
Model Internal
Battery
Internal
Transformer
Internal
Battery
Internal
Transformer
V float 324.0 VDC 324 VDC 324 VDC
V min 216 VDC 216 VDC 216 VDC
I charge 4.0 A 10.0 A 11.5 Amps
4200FA CT/XT User’s Manual 41