The BTECH Ground fault monitor detects dangerous Battery to ground faults.  Whether the fault is from a leaking battery or inadvertent bus connection to the battery Rack, the BGM-500 Detects the Fault and reports an alarm.


Battery systems are not electrically connected to the cabinets or racks supporting them. The cabinets and rack are connected to Earth ground, if current is present on the ground cable then a ground fault exists. BTECH's system utilizes a precise, specialized custom current transducer to detect current leakage. The ground wire runs through the Current Transducer (CT), which is connected to the BGM-500, and the system continuously measures current flowing to ground. If the BGM-500 detects current above a configurable threshold value, it indicates a ground fault alarm. Depending on the alarm behavior configuration, the alarm either latches until cleared manually or clears when alarm conditions are corrected and ground current returns below alarm threshold value. Ground fault alarms can be triggered by positive or negative current, so the CT direction doesn't affect the functionality of the BGM-500.

Battery system ground faults are a dangerous and potentially catastrophic DC plant condition, if left undetected several things can happen:

  • Unintended grounds can expose field service personnel to electric shock.

  • Ground fault conditions can lead to battery system overheating and catastrophic failure.

Thermal Runaway:

  • Battery system discharges with a ground fault present can exacerbate the condition and can lead to a dangerous thermal condition and fire.

  • Battery system life can be severely limited.

  • Battery capacity is reduced.

The BGM-500 can work as a stand-alone product, or integrate into a building management system

The BGM-500 features a very accurate and non-invasive Current Transducer to detect a ground fault


Power Requirements

  • Power Input 1 1 0-240VAC-12VDC Output
  • (AC/DC Power Supply)
  • Max Current 1 A (5 Watts)

Measurement Capability

  • Measurement Range 0-500 mA DC
  • Measurement Uncertainty 1 .0% F.S.
  • CT Sensitivity 0.2% F.S.
  • CT Linearity 0.5% F.S.


  • USB (B)
  • Ethernet (RJ45 TCP/IP)
  • 1 NC/NO alarm relay


  • Operating Temperature 5-40°
  • Operating Humidity 0-80% - (non-condensing) for 0-30°C
  • 0-50% (non-condensing) for 31-40°C
  • Operating Altitude 0-2000 meters

BGM-500 Mounting

  • The BGM-500 can be mounted • ETL,CE Approved directly to the cabinet or rack
  • Wall-mounted inside a NEMA 1 enclosure
  • DIN rail mounted


  • BGM-500- H 4.12"xW 4.3" x D 1.41"
  • Current Transducer
  • CT Sensor Size (packaging) - W2"x H3"x D1.25
  • CT Window Size: 5/8"

Modbus Settings

  • Device ID: 1
  • Address: 0001
  • (Coil Status) - set length to 16
  • Coil 1 : Ground Fault Alarm
  • Coil 2: Equipment error
  • Coil 1 5: Reset alarm
  • Coil 16: Watchdog
  • (Holding Register) - Set length to 2 - IEEE
  • 2 word floating point of current reading

Download a specification sheet with all of this information and more: Spec Sheet