SR250Hi – 250W DC UPS

No – Break ™ DC Uninterruptible Power Supply TECHNOLOGY

The New SR250Hi 250 W power supply is designed to provide DC power to lead-acid batteries for critical backup applications. All the functionality and durability has been retained with a more modern and easier to understand range of products being developed.Form factor and connectivity remains the same, so they will fit into the slots occupied by the old range – the legend continues!

No-Break ™ DC UPS systems maximise the integrity of standby battery installations, whilst optimising the life and availability of back up batteries.  They are now available with Serial and Ethernet Communications options.

The No-Break ™ system is the ideal solution for:

  • Critical systems of 100W to 750W (and above using parallel operation)
  • Applications requiring continuous on-line monitoring of battery and charger status
  • Providing cost-effective management of your battery system investment

Other features include:

  • Ability to view power supply data remotely
  • Automatic or manually initiated battery condition testing to ensure the availability of standby power
  • The battery condition test feature of the No-Break ™ DC system determines the condition of the back-up batteries and will provide an early warning of potential failure. This gives plant operators enough warning to replace the faulty batteries before they are required, like in the event of a mains power failure. Battery condition tests are mandatory on some fire alarm systems and are now commonly specified by consultants for critical industrial systems.


  • Security – Access Control
  • Industrial Processes Switching Protection
  • Radio Repeaters – Remote Sites

Points Of Difference

  • Separate outputs for load and battery.
  • Battery detection—regular battery presence and battery circuit integrity checks.
  • Battery deep discharge protection.
  • Power loss & battery system alarms
  • No transition switching to  backup battery
  • Rugged design and construction for long life and challenging environments

Optional Features

  • American Input Voltage 110 VAC ( 88 – 135 VAC)
  • Communication Port ( RS232 ASCII – SR485 – MODBUS RTU – SNMP , webpages)
  • Digital Input/Outputs: Customizable 3 digital inputs & 1 digital output.
  • Battery Condition Test : Option auto test enabled on start-up
  • Mounting: Rack Mount 19″ with V/I meter available, Wall mount
  • N+1 redundancy
  • Boost Charger
  • Conformal coating for harsh environments



 Model Output (V)  PSU Rated  (A) Charge Limit (A) Recomm. Load  (A) Peak load on power fail (A)
SR250Hi12 13.8 18 9 12 27
SR250Hi24 27.6 9 9 5 13.5
SR250Hi30 34.5 7.2 7.2 3.7 10.8
SR250Hi36 41.4 6 6 3 9
SR250Hi48 55.2 4.5 4.5 2 6.7


Output power 250 W
Input Voltage 180V – 264VAC 45-65Hz
Output Voltages 12V, 24V, 30V, 36V, 48V
Voltage Adj. Range 85% – 105% of Vout
Frequency 45-65Hz
Overcurrent protection Constant current limit under overload and short circuit conditions
Isolation Input – earth – 2.5KVdc
Output – earth – 500Vdc
Efficiency > 85%
Noise <1%
Operating temperature -20  to 50 °C ambient at full load
Humidity 0 – 95% relative humidity non – condensing
LVD Low Voltage Disconnect
LED Indication Green: Batt OK
Green: Power OK
Red: Standby
Alarms Relay Form C contacts  30VDC,2A/110VDC,0.3A,125VAC, 0.5A
AUX (Activated by BCT)
POWER (main fails, PSU fails)
BATTERY (batt missing , batt low, BCT fail)
Temp. Compensation Temperature sensor on 1.7m lead with adhesive pad: -4mV/ °C / cell ± 10%
Battery Charge Current Limit Customizable on request.
Reverse Polarity Battery reverse connection will open internal fuse (and produce alarm)
Battery Monitoring Detects for presence of battery on start up, then every 60 minutes when charge    current < 200mA
Battery Circuit Protection Electronic circuit breaker (ECB) operates under the following conditions:
– Low Battery Volts: Battery Voltage drops to 1.67V/cell
Overload: Max load must not exceed 110% of rated current. Peak loads must be connected to B+ & B– terminals. Not suitable for N+1 connection
Short Circuit:  <2ms, backed up by fuse
Standby Mode Turns off DC output of PSU & allows load to run off battery


Optional Input Voltage 88 – 132 VAC
Communication Port · RS232 (ASCII)
· RS485 (ASCII)
· Modbus RTU
· SNMP, Webpages
Digital Inputs/Outputs Customizable 3 Digital Inputs and 1 Digital Output
Battery Condition Test (BCT) Option auto test enabled on start-up
Mounting · Standalone
· 19”Rack Mount . Optional V/I meter for subrack : SR-Meter
· Wall Mount
Boost Charger Customizable feature on request.



SR Series – Comms Downloads

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