Data Sheet

UB20.241
UB-Series
24V, 20A, DC-UPS
5. BATTERIES AND BATTERY CHARGING
The battery is not included in the DC-UPS. Use one of the PULS 24V battery modules (see chapter 22.4 and 22.5). In
addition to the PULS battery modules, the UB20.241 is also designed to be compatible with a large variety of different
VRLA (Valve Regulated Lead Acid) or SLA (Sealed Lead Acid) batteries from various suppliers.
The battery is one of the most important parts of a DC-UPS system, which needs to be carefully selected while also
paying close attention to storage, charging and environmental conditions. Select the proper size (capacity) according
to the required buffer time (see chapter 6) and the lifetime requirements (see chapter 23.1).
Batteries are service parts and need to be replaced periodically or when the internal battery tests of the DC-UPS
reports a random failure. Information regarding the DC-UPS battery tests and the replacement requirements can be
found in chapter 23.1.
The wiring from the battery to the DC-UPS must follow the instructions in chapter 3. Be aware that the current from
the battery to the DC-UPS can be higher than the load current due to the buffer voltage transformation, which
restores the battery voltage to a constant buffer voltage.
The UB20.241 has a battery size selector included, which allows an optimal use of small and large battery sizes.
It is not recommended to connect multiple batteries or battery modules in parallel. Chose larger sized battery instead.
Charging:
The UB20 comprises a constant current / constant voltage (CC-CV) charging method.
When the center-tap connection is installed, both 12V batteries are charged individually with their own charger. The
center-tap connection is optional and if not installed, both batteries will be charged with one common charging
voltage. The UB20 automatically recognizes if the center-tap connection is present or not.
When charging is approximately 85% completed, the individual green “Ready” LED for the specific battery stops
flashing and is on solid.
During charging, the DC-UPS consumes additional current from the input. The supplying power supply must be able to
deliver the additional required internal current consumption (including the charging current) specified as input current
in the table of chapter 4.
When the temperature sensor is installed, the end-of-charge-voltage is temperature compensated. The UB20
automatically recognizes if a temperature sensor is connected or not. In case no temperature sensor is installed, the
end-of-charge-voltage is fixed to a value which corresponds to a battery temperature of 40°C.
Use a PT1000 temperature sensor or the PULS UZK24 battery modules, which have this sensor already included. A list
of suitable PT1000 temperature sensors from different vendors can be provided.
Setting of battery size selector
small battery
< 10Ah
large battery
> 10Ah
Allowed battery sizes nom. 3.9Ah – 10Ah
5)
10Ah – 150Ah
Battery voltage nom. 24V 24V 2x 12V batteries in series
Battery charging current typ. 1.5A 3A In constant current mode
End-of-charge-voltage typ. 2 x13.25V 2 x13.25V center-tap connected,
no temperature sensor connected
typ. 26.5V 26.5V center-tap not connected,
no temperature sensor connected
typ. 2x 13.1 to 14.2V
1)
2x 13.1 to 14.2V
1)
center-tap connected,
temperature sensor connected
typ. 26.2V to 28.4V
1)
26.2V to 28.4V
1)
center-tap not connected,
temperature sensor connected
Temperature range for which
the charging process is enabled
nom. -10°C to +50°C
2)
-40°C to +50°C
2)
Footnotes can be found on the next page.
Feb. 2016 / Rev. 2.1 DS-UB20.241-EN
All parameters are specified at 24V, 20A output current, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone [phone] Germany
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