BQMS Battery Monitoring System

Model # BQMS

The BQMS is a versatile Battery Monitoring System designed for stationary power applications. Parameters monitored include string voltage, string current, cell voltage, cell/connection resistance, cell temperature, & ambient temperature. The BQMS is designed for use on vented lead-acid (VLA), valve-regulated lead-acid (VRLA), and nickel-cadmium (NiCad) battery systems. Optional add-on components can be included for monitoring electrolyte levels and ground faults.

Included with the BQMS is Eagle Eye’s proprietary Battery Management Software Centroid 2. This software package allows for remote viewing and data management of all connected Eagle Eye battery diagnostic systems. Battery report generation, trending analysis, & detailed alarming can all be viewed on a single or multiple PC’s on the same network as the BQMS. Alternatively, the BQMS can be configured with Modbus or DNP3 protocols. All BQMS systems include dry contacts for external alarming to a DCS.

  • Specifications
  • FAQs
  • Benefits
  • More Info

Technical Specs

Measurement Range:Nominal Cell/Unit Voltage: 2, 4, 6, 12 VDC
Cell/Unit Temperature: -20 – 80°C (-4 – 176°F)
DC Voltage: 0 – 576 VDC
DC Current: ±10,000A
Accuracy:DC Voltage / Current: ±0.5% / ±1%
Temperature: ±2%
Internal Resistance: ±2%
Cell Voltage: ±0.5%
Resolution:DC Voltage / Current: 0.1 V / 0.1 A
Cell Voltage: 0.001 V
Internal Resistance: 0.001 mΩ
Temperature: 0.1°C
Test Speed:30 seconds per battery bank
Test Load:Less than 2 amps per cell/unit
Alarm Relay:Up to (8) Form C
Measuring Interval:Adjustable from 10 min to 160 hours (voltage & I.R.)
Data Transfer:TCP/IP to proprietary software, Modbus TCP/IP
Operating Environment:Temperature: 0 – 65 °C (32 – 150 °F)
Relative Humidity: Under 80%
Power Requirements:CCU: 48V (36 – 72 VDC) / 125V (120 –370 VDC)
Module: 2V (6 – 18 VDC) / 12V (18 –36 VDC)
Dimensions (W x D x H):CCU: 210 x 76 x 197 mm (8.25 x 3 x 7.75 in)
Module: 114 x 70 x 39 mm (4.5 x 2.75 x 1.5 in)


What are some common applications areas for this product?
Common applications include but are not limited to:

  • Power Utilities and Distribution
  • UPS Systems
  • Telecom/Communications
  • CATV Broadcasting
  • Transportation Operations
  • Government/Defense
  • Call Centers
  • Oil, Gas & Fuel
  • Generators
  • Financial Institutions
  • Hospitals
  • Emergency Lighting
  • Green Energy
  • Mining
  • Call Centers
  • Battery Suppliers and Manufacturers
  • Government/Defense
  • Medical/Biotechnology

What hardware / components come with the BQMS?
A complete system will have the following components:

  • Communication Control Unit (CCU) – Processes measurement data and houses communication connections to network.
  • Module(s) – Mount on the battery system in a daisy chain connection. Each module connects to 2-4 cells depending on the voltage.
  • Sensing Cables – Cables which connect to the BMS clamps from the MPU for gathering measurement data.
  • Clamps – Physical connection to the battery system, connects to the inter-cell connections.
  • CT – Hall Effect CT clamp for measuring DC current.

Does the BQMS calculate the capacity of the batteries?
No, the BQMS does not perform a load test, so there is no way for the system to calculate the capacity. The system does detect and record all discharge events to show how each cell performed during the duration of the test.

What are the options for installation of the system(s)?
There are several options for installation:

  • The customer can install the systems with free remote support from trained Eagle Eye technicians.
  • The customer can select a training package for installation of the systems, either onsite training by Eagle Eye’s technicians or at Eagle Eye’s facility.
  • The customer can select an installation package where Eagle Eye technicians perform the complete installation of the system(s).

Can the BQMS monitor battery systems in parallel?
No, the BQMS is designed for testing of a single system.

How does Eagle Eye’s Centroid 2 software work?
The Centroid 2 software is composed of two parts, the server and the client. Centroid 2 Server is installed on a dedicated PC that must be connected to the same network as the BQMS system(s). This software runs in the background on a Windows environment as a service. Centroid Viewer client must also be installed on a PC that is on the same network as the BQMS. The client can be installed on multiple computers and can pull data directly from the PC with Centroid 2 Server running.

How does the BQMS test jar/cell resistance?
The system injects 400mA to 2A (max.) AC current for a duration of 900ms per jar / cell. During the 900ms duration is (3) 300ms tests. The average of these (3) tests is used as the final test result.

Does the battery monitoring system’s AC measurement signal affect the battery’s condition or lifespan in any way?
The level of AC current applied to the battery by the monitoring system during measurement is insufficient to affect battery life, as it is not continuous nor is it a of a level that could cause the temperature to rise during the short period it is applied.

Which parameters are measured in real-time?
String voltage, current, and ambient temperature are measured in real-time, values are continually updated on the BQMS screen and in the software.

Which parameters are measured on interval and what is that interval?
Cell voltage, cell resistance, and cell temperature are measured on set intervals. These intervals can be set at any time from every 10 min. to once daily. In the event of a discharge these parameters will be measured continually until the discharge has ended.

How long does the system take to measure the resistance of the whole string?
About 30 seconds.

What are the ratings of the Dry Contacts?
Nominal Rating - 2 amps at 60 Volts  AC/DC
Max Ratings - .5 amps at 250 volts AC / .27 Amps 220 Volts DC

What are the communication options for the BQMS?
There are two standard communication options for the BQMS (only one communication method can be utilized per system).

  • TCP/IP to Eagle Eye’s proprietary software Centroid 2 – This option provides the most information about the health of the battery system as the software was specifically designed to take full advantage of the BQMS measurement data.
  • Modbus protocol over TCP/IP – This option should be used if the measurement data will be integrated into an existing building management of SCADA system. (External PC required per system)

Are there any options for using Eagle Eye’s software in addition to Modbus protocol?
Yes, a single BQMS can communicate via TCP/IP to a dedicated PC with Centroid 2 installed. Through the software, Modbus protocol can output from the PC. Each BQMS system requires its own server PC for this solution and is offered as complete kit.

Is the BQMS hardware rated as explosion proof?
The hardware is not officially rated as explosion proof, however it was designed to be mounted and exposed permanently in a battery room environment. If ex-proof is absolutely required then cabinet solutions are available to meet any specific requirements.

Can the BQMS measure lithium battery types?
No, currently the system cannot measure any type of lithium battery.

Do the BQMS modules need to be grounded?
No, the modules do not need to be grounded because they are powered by DC from the battery.

What frequency does the BQMS use during measurement?


  • True 24/7/365 Battery Monitoring
  • Installation and maintenance can be done while battery systems are online
  • Meets IEEE and NERC standard recommendations for battery monitoring solutions
  • Utilizes a patented ripple-removing algorithm for the most precise and repeated results in any environment
  • Injects a minimal current, allowing the user to test their battery multiple times a day without adverse effects on your battery or battery monitoring system
  • Includes up to 8 Form C Contacts for external alarming
  • Simple to install with custom (to your batteries and site), pre-assembled installation materials
  • Can monitor all your systems in real time with flexible expanding solutions
  • Can be powered by AC or DC
  • Includes battery management software for:
    • Battery trending
    • Creating battery reports
    • Displays VDC and IDC in real time
    • Displays Voltage, Resistance & Temperature Per Cell
    • Sends an email to the person in charge if battery is at a warning or failure level
    • Records discharge & recharge and can be played back to view system and battery level performance during discharge

Note: Modbus protocol can be provided if the user would like to transmit the test results to their management system.

More Info

The BQMS Battery Monitoring System Includes:

  • Measuring Module(s)
  • O-Clamps for inter-cell cable connections
  • C-Clamps for inter-cell busbar connections
  • Cabling for all measurement connections
  • CT Clamp for DC current measurement
  • Centroid 2 Battery Management Software
  • User Manual
  • Optional: Spare Parts Kit

Before installation of the BQMS, Eagle Eye will send you an BMS-Series Site Survey Form. This site survey form allows us to customize your BQMS battery monitoring system based on your batteries, network, and battery site.

Battery failure can happen overnight, and Eagle Eye’s real-time battery monitoring systems allow full protection and confidence against such failures. Ohmic resistance and voltage measurements (per jar) are taken as often as every five minutes. String current, DC voltage, and temperature are measured in real-time. These measured parameters will provide the user a real-time understanding of their batteries state-of-health. Ohmic resistance results represent the condition and state-of-health of the battery, and expose weaknesses in cells & intercell conditions without stressing the battery. Cell and string voltage results can indicate if the battery is fully charged or if there are problems with the battery or charger. Stable temperature results indicate a proper operating environment, while high recorded temperatures can be a sign of thermal runaway.

Use the BQMS battery monitoring system to measure these parameters to protect the integrity of your system, and exceed industry testing requirements by IEEE and NERC. Request a battery monitoring quote online now with your battery monitoring requirements.

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  • Model #

    Battery Monitoring Solution for Stationary Power
    2V, 6V, or 12V Cell/Units up to 1,000V

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Companies We Serve
  • Duke Energy: Battery Monitoring SystemAES
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