Powerware
®
Plus 12 Operator's Manual (164200090 Rev E) 49
Installing Remote Batteries
The following sections describe how to determine the battery capacity and install and
configure the remote batteries.
Determining the Battery Capacity
When a battery cabinet is not supplied with the UPS, DC power can be supplied by remote
batteries. It is recommended to use sealed maintenanceĆfree, leadĆacid type batteries.
To determine the battery capacity you need for your UPS:
. Determine the active load KW and load power fact PF of the critical load to be
protected by the UPS. KW is calculated from the apparent power kVA and the
load power PF as:
(KW) = (kVA) PF
. Determine the power to be delivered by the battery KW
Batt
. The efficiency of
the UPS is taken into consideration and can be calculated using the following
expression:
(KW)
0.85 - 0.05 (1 - PF)
(KW
Batt
)=
. Nominal battery voltage is 240 Vdc (120 cells @ 2.0 Vdc). Float voltage should
not exceed 270 Vdc.
. Determine the desired backup time and the operating temperature.
. The lowĆbattery shutdown voltage is customerĆselectable. It can be set
between 1.67 Vdc/cell and 1.85 Vdc/cell. Select a value suitable for your
application to size your battery and make sure you set the value when
configuring the UPS.
. Follow the battery manufacturer's application notes and charts to calculate the
battery capacity necessary for your application.
. The UPS has a cyclic battery charger (turn on = 265 Vdc, turn off = 285 Vdc)
that delivers a maximum current of 5 amps. The internal charger must be
disabled when an external charger is used. For battery sizes above 75 AH, an
external charger is recommended.
Remote Battery Installation
The following instructions assume you have already installed the UPS according to the
instructions beginning on page 34.
Do not add remote batteries if a battery cabinet is already connected to
the UPS.
. Refer to the battery manufacturer's operator's manual for battery installation
and maintenance instructions.
. Remove the knockĆout for the conduit as shown in Figure 23.
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