Powerbox PB251A-RM SERIES DC-UPS / Battery Charger - 19" Rack Mount
The Powerbox PB251A-RM Series DC-UPS and Battery Charger is a robust 19" rack-mountable power solution, delivering 220-330W of reliable DC power and intelligent battery management. Designed for critical applications, it is ideal for telecommunications, industrial systems, and backup power solutions. Key features include constant float voltage an...
Read MoreThe Powerbox PB251A-RM Series DC-UPS and Battery Charger is a robust 19" rack-mountable power solution, delivering 220-330W of reliable DC power and intelligent battery management. Designed for critical applications, it is ideal for telecommunications, industrial systems, and backup power solutions.
Key features include constant float voltage and current limiting, independent battery charging outputs, and advanced alarms with relays for real-time monitoring of DC and battery status. The system supports optional features like battery charge current limits, network connectivity via SNMP V1 and embedded webpages, and temperature compensation for optimal battery performance.
Available in 13.8Vdc (20A) and 27.6Vdc (12A) configurations, the PB251A-RM Series offers flexibility for a wide range of applications. With natural convection cooling, automatic over-temperature protection, and compliance with AS/NZS60950 safety and C-Tick EMC standards, it ensures reliable performance even in demanding environments.
The Powerbox PB251A-RM Series is the perfect choice for rack-mount installations requiring dependable DC power, advanced battery charging capabilities, and seamless system integration.
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Features
- Trusted in Critical Applications: Widely deployed in radio communications, nurse call systems, and security/access control infrastructure, the PB251A-RM provides dependable backup DC power for mission-critical systems where continuity is essential.
- True Off-Line DC-UPS Functionality: Seamlessly delivers power to connected loads from the AC mains during normal operation and automatically switches to battery backup during outages—ensuring uninterrupted operation without dips or reset events.
- Compact Rack Mount Design: Housed in a 2RU 19" rack-mount enclosure, with models delivering up to 330W of output power at 13.8Vdc or 27.6Vdc, this unit fits easily into communication racks, control rooms, and centralised power cabinets.
- Comprehensive Battery Management: Includes built-in battery low-voltage disconnect (LVD), constant float voltage, current limiting, and auto-resetting circuit protection. A digital display and alarm relays provide real-time system status and fault indication.
- Various Options Available: Including SNMP V1 network interface for remote monitoring, analogue meters, temperature compensation, and factory-set battery charge current limits tailored to battery specifications.
- Designed and Manufactured in Australia: Proudly engineered and built by Powerbox in Australia, the PB251A-RM reflects decades of local expertise and compliance with Australian standards for safety, EMC, and industrial performance.
Specifications
| INPUT | |
|---|---|
| Input Voltage: | 190...264Vac, or 225...400Vdc |
| Frequency | 45 to 65 Hz |
| Input Current: | 1.4A maximum |
| Inrush current: | 10A maximum |
| Line regulation: | 0.2%typical |
| ALARMS & BATTERY FUNCTIONS | |
|---|---|
| DC Ok alarm | Green LED : ON=OK voltage free change over relay contacts (32V,1A) Alarms on loss of AC mains power or failure of off-line AC/DC converter / battery charger |
| Charger voltage OK alarm | Green LED : ON=OK voltage free change over relay contacts (32V,1A) Alarms on battery low voltage, failure of battery fuse or battery disconnected. Alarm cancelled when fuse or battery replaced, or AC input restored |
| Battery low voltage disconnect(LVD) | Low voltage disconnect 10.5V for 12V battery, 21V for 24V battery, adjustable 1.6 to 2.0V / cell all models |
| Charger over-load protection | Auto-resetting electronic circuit breaker |
| Reverse polarity protection | Internal battery fuse |
| Battery to load voltage drop | 0.2 to 0.35V typical model dependant |
| OUTPUT | |
|---|---|
| Output Voltage | 13.8Vdc, 27.6Vdc |
| Output Power | 275W - 330W |
| Output Current | 13.8Vdc: 20A 27.6Vdc: 12A |
| Load regulation | 0.5% typical |
| Ripple & noise | 100 MHz bandwidth 28mVp-p (13.8Vdc output) 55mVp-p (27.6Vdc output) |
| Efficiency | > 80% |
| ENVIRONMENT | |
|---|---|
| Operating temperature | 0 to 70°C ambient Derating from 40°C at 2.5%/°C |
| Humidity | 5 to 90% relative humidity (non-condensing) |
| Over-temperature protection | Automatic & auto-resetting |
| Cooling requirement | Natural convection |
| MECHANICAL | |
|---|---|
| Input connector | IEC60320 inlet,10A Class 1 2 meter IEC mains cord with Australian plug is supplied with each unit |
| Output and battery connector | PB251A-RML: M4 screw terminals |
| Alarm terminal | PB251A-RML: M3.5 screw terminals |
| Enclosure | 19" Rack Mount, 2RU height, 232mm Mounting slots suitable for M6 hardware |
| Weight | 5.5kg |
| STANDARDS | |
|---|---|
| C-Tick | AS/NZS CISPR11 Group 1 Class A. |
| Safety | Complies with AS/NZS 60950, class 1, NSW Office of Fair Trading Approval N20602 |
| EMC | Emissions comply with AS/NZS CISPR11, Group 1, Class B. Complies with ACA EMC Scheme, Safety & EMC Regulatory Compliance Marked |
| OPTIONAL FEATURES | |
|---|---|
| Battery Charge Current | Factory set to any value within adjustment the range. For the PB251A-12RML, battery charging current limit can be set from 2A to 20.5A . For the PB251A-24RML battery charging current limit can be set from 1A to 12.5A . Battery charging current option can be specified when ordering e.g. PB251A-12RML-10 for 10A setting. |
| Network enabled | Option N: Internal network card in conjunction with PB251A becomes a network enabled device combining the benefits of SNMP V1, XML and embedded webpage. |
| Analogue meters | Option M: Load voltage, load current, battery charge and discharge. |
| Temperature compensation | Option T: 2.5m cable probe Option T5: 5m cable probe Float voltage set to 2.3V/cell at 25°C with compensation of 3.3mv/°C cell |
| Battery Capacity Test | Contact Powerbox for further information |
Selection Table
| MODEL NUMBER | OUTPUT VOLTAGE | LOAD CURRENT |
BATTERY CURRENT LIMIT (BCL)¹ |
TOTAL CURRENT | OUTPUT POWER | MECHANICAL |
|---|---|---|---|---|---|---|
| PB251A-12RML | 13.8V | 16A | 4A | 20A | 275W | 19" Rack Mount |
| PB251A-24RML | 27.6V | 10A | 2A | 12A | 330W | 19" Rack Mount |
Notes:
¹ Other BCL option, Battery Charging Limits, available on request. (factory set)
² Example models number, PB251A-12RML-M-10, Includes analogue meters and 10A battery charge current.
Technical Drawings
Warranty & Returns
Warranty periods vary by product. Please refer to the Powerbox Warranty Policy for the applicable coverage period against manufacturing defects from date of purchase. For returns and RMA requests, please visit our RMA support page or contact our support team directly.