48 Chapter 6 Battery
Liebert APM 90 Integrated Modular UPS User Manual
Temperature
Table 6-1
Ambient temperature range
Type
Temperature value
Remark
Recommended
optimal
temperature
20
°
C
~
25
°
C
Short time
allowable
temperature
-15
°
C
~
45
°
C
The ambient temperature for the battery operation shall not be too high
or too low.
If the average operating temperature of the battery rises from 25
°
C to
35
°
C, the service life of the battery will be reduced by 50%. If the
operating temperature of the battery is over 40
°
C, the service life of the
battery will be reduced exponentially each day
The higher the temperature is, the shorter the battery service life will be. At low temperature, the
charge/discharge performance of the battery will be significantly reduced.
The battery must be installed in cool and dry environment with the humidity less than 90%, and be protected
from the heat source and direct sunshine.
The ambient temperature, ventilation, space, float/equalizing charge voltage and ripple current will affect the
battery temperature. Uneven temperature among the battery strings will cause uneven voltage distribution
and thus result in problem. Therefore, it is very important to maintain balanced temperature in the battery
string, and the temperature difference between batteries of different layers shall be kept within 3
°
C
.
Valve-regulated battery is very sensitive to the temperature, therefore, valve-regulated battery shall be used in
15
°
C
~
25
°
C
. If the battery cabinet is installed near the UPS, the maximum design ambient temperature shall
be determined according to the battery rather than the UPS. That is, if valve-regulated battery is used, the
indoor ambient temperature shall be 15
°
C
~
25
°
C
rather than the operating temperature range of the main
equipment. Under the precondition that the average temperature will not exceed 25
°
C
, it is allowed to have
short time temperature deviation.
6.5.2
Number Of Batteries
Set the DC bus voltage and battery float charging voltage, which is usually 490Vdc, according to the rated
input/output voltage of the UPS, to ensure that the expected cell float charging voltage is 2.27V. The number
of batteries, EOD voltage, float charging voltage under the 380V/400V/415V voltage system are consistent, as
shown in Table 6-2.
Table 6-2
Number of batteries
Parameter
380V/400V/415V
Number of cells (standard)
216
~
240 pcs
End of discharge voltage
1.60Vdc/Cell
~
1.88Vdc/Cell
Float charging voltage
2.15Vdc/Cell
~
2.3Vdc/Cell
6.6
Battery Protection
The battery is connected to the UPS through the BCB. The BCB can be manually closed. If the battery adopts
rack mounting or is far away from the UPS cabinet, the BCB shall be installed as close to the battery as possible,
and the wiring distance of the power and signal cables connected to the UPS shall be minimized.
The BCB should provide:
Over-current protection
Short circuit protection
Automatic tripping function
To obtain the required backup time, the batteries may be connected in parallel. In this case, each battery
string must be connected to a separate BCB.