SR500i – SR750i

DC UPS – No – Break ™ DC Uninterruptible Power Supply TECHNOLOGY 

Helios Power Solutions proprietary No-Break ™ DC UPS Technology represents a truly unique, comprehensive approach to providing uninterruptible and secure DC power when you need it.The system maximises the integrity of standby battery installations whilst optimising the life and availability of the backup batteries.

The No – Break ™ DC UPS intelligent system provides a vastly improved solution over the traditional methods of float charger plus battery. The battery is accurately charged with independent current limit and you cannot overload the charger or overheat the battery.

The No – Break ™ DC UPS highly efficient system is the ideal solution for:

  • Systems which require no transition from mains to battery backup
  • Applications having standing load with back up standby battery installed
  • Cost-effective management of your battery system investment
  • Mission Critical systems from 100W to 750W and above.

Critical factors in the lifetime and capacity of (lead-acid) batteries

  • Temperature compensation
  • Controlled charge current
  • Regular check up
  • Deep discharge protection

Unique additional features of the No – Break ™ DC UPS system

Battery Detection: Monitors integrity of battery circuit hourly (battery missing, open fuse/electronic breaker)

Battery Condition Test (0ption): Indicative test of battery autonomy at predetermined intervals (automated battery condition check, ideal for remote sites).

Configurable Software 

Adjustable Load 

Communications Interface Port: (Options RS485 , RS232 , Ethernet)


ModelOutput (V) PSU Rated  (A)Charge
 Limit (A) *1
Recomm. Load  (A)


  •  Why is Helios Power Solutions SR No-Break ; DC charger recommended by consultants for critical applications?

Our No-Break ™ DC chargers have been designed for industrial use and have over twenty years of proven reliable operations.  In addition, the chargers have many outstanding features such as fault alarms, LED fault alarm codes, battery detection, low voltage disconnect circuitry, automatic battery condition testing, communication options and can be connected to the battery permanently due to the precise temperature-compensated voltage control.

  • Why should we use a SR No-Break; as opposed to a normal float charger?

The No-Break ™ DC UPS  has many features which a normal float charger does not, these including:

    • Precise alarm indication for mains or DC faults
    • Overcurrent protection on the battery circuit
    • Battery presence checking
    • Temperature-compensated charging
    • Low voltage disconnect circuitry to prevent deep discharge of the battery
    • Independent charge current limit
    • Automatic battery condition testing
  • Why don’t you use a boost charge on the SR No-Break unit?

Normally it is not necessary to have a boost on the No-Break ™ unit, as the power is on the system continuously and it is not that critical to restoring 100% of charge rapidly, as in the case of cyclic applications.  A boost charge voltage may damage the equipment which is permanently connected to a standby system.

  • Can I use the SR No-Break DC UPS without a battery?

No, the No-Break ™DC UPS is designed to operate with a battery connected and instability may result if there is no battery connected.  If you wanted to do this then it is advisable to use a standard two-terminal DC power supply SR500L – SR750L

  • Why is the battery negative separate from the load negative in the SR No-Break DC UPS?

This is done to implement two of the features of the No-Break ™ UPS/charger.  There is an “electronic circuit breaker” fitted between the battery negative and load negative terminals to provide the battery overcurrent protection.  The separate battery circuit also allows for independent control of the charging current when required.

  • Can I connect the battery directly to the load terminals when using SR No-Break DC UPS?

No, it would nullify all the features of using the No-Break ™DC design and provide false alarm signals from the relays.  If you wanted to do this, then it is advisable to use a standard two-terminal float charger, with or without alarms.

  • When does the SR No-Break system disconnect to protect deep discharge of the battery?

At approximately 1.67 volts per 2V (nominal) cell, so for a 12V system the disconnect voltage is set at 10V.

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