• Over 25,000 products in stock
  • clock Stock items ordered before 15:00, will be dispatched on the same day
  • Read more about us


24 V dc UPS for external battery 3.9-130 Ah

  • Load current 20 A
  • Control of each individual battery
  • Selectable output voltage in battery mode
  • Temperature compensated charging
  • Relay outputs for status

Product description

The UB20.241 uninterruptible power supply controller (DC-UPS) is used in addition with a 24V power supply and batteries to bridge power failures or voltage fluctuations. This configuration can prevent expensive downtimes, long restart cycles and loss of data.

A unique feature of the UB20 series is the constant voltage in battery mode, which will not change as the batteries discharge. The buffer voltage in battery mode can be set to four different output values. Another feature is the utilization of two independent battery chargers for the two 12V-batteries in series. This feature makes matching batteries unnecessary and allows for precise battery charging, testing and optimized usage of the battery capacity to achieve the longest battery service life.

The UB20.241 includes many battery diagnostic functions that ensure a reliable operation of the entire system. Furthermore, a temperature controlled charging

extends the life of the batteries. It also includes a selectable buffer time limiter as well as ready, buffering and replace battery contacts. For safety and

maintenance, an inhibit input signal is included which prevents a battery backup.

Technical Data


Input voltage from the unit

24 V DC (23.3-30 V DC continuous operation)

Input voltage from the battery

2x12 V DC two batteries in series

Output voltage during normal operation

0.15 V DC lower than the input voltage from the power supply

Output voltage in battery mode

Selectable via switches in the front. 22.5, 24, 25 or 26 VDC.
The voltage of the power supply must be 0.8 VDC greater than the selected area.

Output current during normal operation via the unit (max.)

25 A. If feeding unit is greater than 28 A, a 25 A fuse between the unit and the control unit is installed.

Output current in battery mode (max.)

20 A (30 A for 4s, then the output is set in the "hick-up" mode)

Input current internal consumption type

70 mA

Input current when charging from supply 24 V DC

1.7 A battery switch in position <10 Ah

3.4 A battery switch in position >10 Ah

*The total input power when the battery is charging

1.77 A or 3.47 A


Permitted battery sizes

3.9-130 Ah

Charging the battery type

1.5 A battery switch in position <10 Ah

3 A battery switch in position >10 Ah

Charging type

Ex. 8 hours 12 Ah completely discharged battery

Voltage level of the connection of the battery

Identical to the selected output voltage in battery

Selectable buffer times

10 s, 30 s, 1 m, 3 m, 10 m alt. endlessly until deep discharge protection becomes

Buffer with 2x7 Ah battery **

Min. 13.3 min at 10 A. Typ. 16.53 min at 10 A

Min. 4 min at 20 A. Typ. 5.12 min at 20 A

Buffer with 2x12 Ah battery **

Min. 35.3 min at 10 A. Typ. 44.3 min at 10 A

Min. 11.53 min at 20 A. Typ. 14.51 min at 20 A

External temp.

PT-1000. See the "Wiring" tab.

Power loss type

3.7 W Supply via power supply, 20 A load current and the battery is fully charged.



22.7 W. Supply via battery, 20 A load current

Operating temperature controller

-40 to +70 °C (some power reduction over +60 °C).
Please also note the battery specifications.

Connection power

Screw connection. 2.5-4 mm² multifilament, 2.5-6 mm² monofilament

Connection signal contacts

Connector terminals. 0.2-1.5 mm²


700 g

Dimensions WxHxD (mm)

46x124x127. (Supplement for signal contacts in height and DIN rail length)

Signal contacts

Ready. Controller ready for backup.


Buffering. Control of backup / battery mode.


Repl. Bat. Battery replacement

Input inhibit

External shutdown by 24 V DC. Min. pulse time 250ms. Max 35 V DC.

MTBF enl. SN 29500, IEC 61709, 20 A and 40 °C

649 000 hours (Operation with power supply)


CE, UL508 Listed, UL 60950-1, CB-Scheme


EN 61000-6-1, EN 61000-6-2, EN 61000-6-3, EN 61000-6-4.
FCC Part 15 Class B. EN55011/ EN55022 Class B

Compliant standards

EN/ IEC 60204-1, EN/IEC 61131-2, EN50178, IEC 62103

* The total input power must be deducted from the unit's rated current, the result is the maximum available load current. Ex. 20 A units is the maximum load current 16.53 A with battery> 10 Ah. 3.47 A is used for internal consumption and charging of the batteries.

The minimum value of 20% include the aging of the battery and a cable length of 1.5 meters with the area 4 mm² between battery and controller.


Backup times

Discharge curve
A-curve= 7 Ah batteries
B-curve= 12 Ah batteries




Dimensions & wiring





  • A. Pluggable connector for alarms / diagnostics
  • B. Connection of power supply and output
  • C. Red LED. Wrong indication. Ex. Blown fuse, input voltage lower than the selected voltage
  • D. Yellow LED. Diagnostics. Ex. Changing the battery, inhibit input activated, the overload of output
  • E. Green LED. Status. The operating status of the DC UPS. Mains, battery, refreshing, charge
  • F. Changeover switch for battery size
  • G. Changeover switch for back-up time. 10 s, 30 s, 1 m, 3 m, 10 m or infinite.
  • H. Selection of the output voltage in battery mode
  • I. Connectio of battery
  • J. Pluggable connector for the temp. sensors, center pin and communication with active battery module


Connecting the center tap of the treatment of the batteries separately

For optimized charging and longevity required that each battery is controlled separately. We recommend connecting the midpoint of the batteries with a center drain connection on the controller to achieve maximum performance. Install a 4 A fuse between the battery and the controller.
If the center pin is not connected works UB20.241 as other DC UPS with two batteries connected in series. It is possible to replace existing DC UPS systems with UB20.241.


Connection of a complete DC UPS systems



Install the battery so that it does not get heated by adjacent equipment and ensure that there is proper ventilation according EN50272-2.



Part Numbers

Order number



DC-UPS module for battery. 24 V DC/20 A


Battery holder for DIN rail. For battery 7 Ah


Battery holder for DIN rail. For 2x12 Ah batteries





DC-UPS modul. 24VDC. 20A.

spinner symbol


Input Voltage From The Unit 24 V DC
Input Voltage From battery 24 V DC
Input voltage for battery connection 22,8 V DC
Input Current During Charging Of Aggregates 3,4 A
Type Power Supply DC-UPS
Output current at 24 V dc 20 A
Power Reduction Of 60 To 70 ° C 12 W/°C
Output Voltage at Battery 22,5
Output Voltage Normal Operation 24 V DC
Output current for battery operation max 20 A (30 A @ 4 s)
Output Current During Normal Operation Via The Unit Max 25 A
Ripple. max 120 mV pp
Temperature Range Without Derating From -40 °C
Temperature Range Without Derating To 60 °C
Efficiency 99 %
Life span 122 000 h @ 20 A, 40 °C
MTBF (IEC 61709) 649 000 h @ 20 A, 40 °C
Width 49 mm
Height 124 mm
Depth 117 mm
Weight 0,7 kg
Approvals ABS, CB, CE, CSA, CSA US, EAC, EX, GL, IECEx, UL
Material Protection Aluminium
IP Class IP20
Charging The Battery Type 3 A
Voltage Level Of The Connection Of The Battery 24 V DC
Permitted Battery Sizes 3,9-150 Ah
Contact us

Please contact us for more information.

Send e-mail Send e-mail