Guardian Access M44 DC Power System

Product Information

Guardian M44 is a 6RU or 7RU high 19” rack-mounted, integrated DC power systems providing an output of 48VDC. These systems can accommodate between eight (6U) and twelve (7U) Guardian family FMPe30.48J hot-swap rectifiers or FPV30.48G hot-swap solar converters.

A load current of up to 700A is available with software controlled battery charge current subject to an overall 700A load plus charge. The rectifiers / solar converters are internally fan cooled with speed control which is a function of load and temperature, keeping acoustic noise to a minimum.

The DC output circuits can provide up to 23 loads which utilize circuit breakers with capacities from 4A to 150A plus up to six 100A to 300A breakers that provide battery protection. An optional programmable low voltage battery disconnect + shunt (LVBD) with 600A capacity is available for use with Lead Acid batteries; while an optional partial load disconnects (PLD), rated at 350A and also programmable, can provide non-critical load shedding when operating on batteries. When the LVBD option and battery breakers are not required the maximum number of available load breakers increases to 23.


Features and Options
  • Rectifiers or Solar Converters
  • 60A to 700A Capacity
  • Remote Monitoring & Control
  • Field Replaceable Controller
  • Ethernet Comm. with SNMPv3
  • 4 or 10 Form-C Relay Alarms
  • Up to 23 Load Breakers
  • Up to 6 Battery Breakers
  • LCD Display & Keypad
  • Easy Installation
System Voltage-48VDC nominal | -53.5 float (factory default setting, user adjustable)
Maximum Capacity @ 230/400VAC nominal Load - 600A with LVBD & Shunt | 700A without LVBD & Shunt
Battery - 600A discharge with LVBD & Shunt | 700A discharge without LVBD & Shunt
(s/w controlled charge)
No. Rectifier / Solar Converter Slots 8 (6RU) or 12 (7RU)
Load Circuits Up to 23 (4A to 150A)
Battery Circuits 1 2, 4 or 6 x (100A, 125A, 200A, 250A or 300A)
Rating 1 input, 8 rectifiers - 230Vac/400Vac, 3W+N+PE, 42A, 50/60Hz
1 input, 12 rectifiers - 230Vac/400Vac, 3W+N+PE, 56A, 50/60Hz
Maximum Input Current 1 input, 8 rectifiers - 52.5A per phase @ 185-276VAC
1 input, 12 rectifiers - 70A per phase @ 185-276VAC
Rectifier Power Factor>0.98 (typical)
Surge ProtectionOptional
Rating Nominal MPPT: 160-300 V DC
Maximum Input Current 17.6A, 1 input each module
Alarm Relays4 standard, option for 10
Local Interface 4 x 20 LCD, 4-keypad, USB / RS232, microSD card slot (32GB max,) for data logging
Remote Interface Ethernet / Modem using PowCom™ software package
Ethernet port allows monitoring and control over a IPv4 or IPv6 TCP/IP network.
Web browser support + SNMP v2c and v3
LED IndicationsGreen - System ON; Yellow - Message(s); Red LED - Alarm(s)
External Digital I/O 2 x Inputs, 2 x Outputs (Open Collector)
Symmetry Inputs6 or 12 (can be redefined as analog inputs up to 100VDC)
Low Voltage Battery Disconnect (LVD) 1 x 600A Programmable
Partial Load Disconnect (PLD) - optional 1 x 350A Programmable
Temperature Compensated ChargingProgrammable
EMCEN 300 386; EN61000-6-3 (Emission); EN61000-6-2 (Immunity)
SafetyCAN/CSA C22.2 No 62368-1:2014; UL 62368-1:2014; EN 62368-1:2014/A11:2017
Operating Temperature-40ºC to +55ºC
Storage Temperature-40ºC to +85ºC
DIMENSIONS, ins. (mm)
6RU 18.9 (481) W x 10.5 (266) H x 15.7 (400) D
7RU 18.9 (481) W x 12.2 (310) H x 15.7 (400) D
1. Not required when installed with battery systems that include their own isolation breakers.
2. Not available when installed with battery systems that include their own management system.
Battery Tests Automatic or manual testing of batteries up to six times per year, results saved to SD card. Variables include test duration and end voltage. Battery discontinuance test to ensure battery connection.
Site Logs System tools developed to assist site management. Daily peak load and statistic logs available.
Load Shedding (PLD) Optional feature that allows voltage or time controlled disconnection of non-essential loads.
Enhanced Battery Monitoring Monthly logging of essential battery parameters including temperature, temperature hours, current, charging voltage and symmetry voltage, Data logged for 5 years.
VRLA Specific Functions
Battery Disconnection Programmable voltage controlled disconnection of batteries.
Battery Charging

Manual time controlled or automatic boost charging with adjustable time and voltage levels.

Symmetry Measurement Optional tool that measures VRLA batteries for imbalance, health and early detection of thermal runaway.  
Temperature Compensation Continuous adjustment of output voltage according to battery temperature. Features include adjustable compensation factor and separate thresholds for high temperature alarms.  
Lithium Guardian Specific Functions  
Communication RS485 communication to Battery Units. Collects BMS data including voltage, current, temperature, lifetime data, and more. All data available via PowCom software, or TCP/IP.  
Battery Disconnection Programmable State of Charge or voltage controlled disconnection of batteries.  
Battery Charging Manual, or Automatic voltage and current controlled charging of Batteries.  
Energy Balance Technology Compatible with EBT charging and balancing of batteries.  
Load Shedding (PLD) Optional feature that allows for State of Charge, voltage or time controlled disconnection of nonessential loads.