Eagle Eye Power Solutions

Vigilant: Next Generation Battery Monitoring System

The ground-breaking Vigilant Battery Monitoring System (BMS) with Advanced Multi-Function (AMF) sensors employs several new battery parameters to predict battery condition. Included in these critical parameters are Battery Cell Condition, Battery State of Health, and Battery (at) Risk Factor. These new features are made possible by machine learning algorithms built into the Vigilant.

The following key battery parameters are monitored and recorded by the Vigilant: string voltage, float current, cell voltage, cell resistance, terminal & connection resistance, cell & ambient temperature, dc ground fault, and electrolyte level.

Web-Based, Remote Battery Monitoring

  • A key advantage of the Vigilant is how it processes measurement data
  • Rather than simply read and display measured parameters, the Vigilant also uses Artificial Intelligence to calculate the SoH of the battery
  • Measurement data and analysis is done via a built-in web-server, which can be accessed with any browser
  • The web-based software eliminates the need for a standalone software package and is viewable on a desktop or mobile environment

Predicting Battery Condition

The Vigilant utilizes several technologies new to the battery monitoring industry to predict battery failure:

  • Battery Cell Condition: Using machine learning algorithms to accurately calculate deterioration much earlier than current Ohmic testing methods
  • Battery State of Health: Algorithms encompassing 12 key parameters to estimate the health of the battery as a whole. It includes measured changes in internal & external factors and in all parameters that could identify a potential reduction in anticipated battery life
  • Battery Risk Factor (RF): Employing individual cell SoH along with temperature and ripple current to better predict risk of battery failures
  • True Float Current: Vigilant’s Advanced Multi-Function (AMF) sensors measure true float current without the remanence and temperature problems of Hall-effect transducers

Check out our library of battery monitoring support videos.

Visit Eagle Eye University for information on our battery training courses.



Working Voltage0.05 – 18.5VDC
Voltage Resolution± 1mV
Post Temperature Resolution± 1ºC
Cell Resistance Resolution± 7μΩ
Strap Resistance ResolutionAt 100μΩ strap r: ± 2μΩ
Float Current ResolutionAt 100μΩ strap r: ± 1mA
Charge/Discharge CurrentMax 800μΩ strap r: ± 0.1%
Max 400μΩ strap r: ± 0.1%
Range: 2,000A
Electrical Supply (from DC supply)36 – 72VDC, 90 – 300VDC, 280 – 580VDC
Other Power Options24V mains supply
System Internal Powervia comms system
Operating Power (from charger)@ 60 cells: 25W
Operating Temp Range-4 – 70 ºC (25 – 158ºF)
Isolation I/P to O/P1000VDC
Test current @ 2.5V20A
Onboard StorageSSD
Memory Capacity20 years of battery data average, expandable for larger systems
Local Data DownloadVia USB port
External ProtocolsModbus TCP/IP, DNP3 (in development)
Network InterfaceRJ45 Ethernet
Dimensions (L x W x H)Sensor: 50 x 50 x 25 mm (2 x 2 x 1 in.)
Monitor: 242 x 200 x 65 mm (9.5 x 8 x 2.6 in)


Vigilant is a distributed battery management system, does it have any parasitic effect on the cells?
No. Although each sensor in the Vigilant system is connected to the terminals of a cell, unlike other distributed sensor systems the power for the sensors is supplied from the system manager. No power for the sensors comes from the cells. The only power drawn from the cell is a momentary test current, once a day.

How does the Vigilant system test for cell and strap resistance? Is it safe for the cell? Is the discharging of the cell during the test significant?
Each sensor draws a high test current for a very short time from each cell, this results in a very small momentary change in the terminal voltage. The waveshape and parameters of the change in the terminal voltage are analysed, and from this the Vigilant machine learning algorithms can determine not only the cell and strap resistance, but also the state of health of the cell.
The sensors analyse the cell energy and automatically optimise the test current to maintain a safe level of test. The actual energy drawn from the cell during the test is insignificant to the battery and is not detrimental to the cell in any way.

Does the Vigilant system use Hall-effect sensors to monitor charge and discharge currents?
No, in most battery systems the Vigilant system measures all currents, float, charge and discharge using its Advanced Multi-Function (AMF) sensors. The high accuracy measuring circuit within each sensor can measure most charge and discharge currents, depending on the battery architecture. Except for very high current measurement, purchasing additional Hall-effect transducers is normally not necessary; Vigilant can do this for multiple strings.

I don’t have any mains power available in the battery room, can the Vigilant be powered from the battery DC, or do I have to make other arrangements?
Three models of Vigilant system monitor/manager are available, which can be supplied by batteries ranging from 48volts (24 volts by special request) up to 600volts DC. Also, if preferred, any Vigilant system can be powered from a standard mains power supply at 24VDC.

Do I need long runs of cable in wiring looms to install the Vigilant system?
No, one of the advantages of a distributed system is that long runs of multiple cables (wiring looms) are not required. A significant disadvantage of long cable runs is that they act as aerials for system noise. The first distributed battery monitoring system was designed in 1997 by Vigilant company personnel, and the advantages of modern distributed BM systems mean that they have since become the ‘go to’ system of choice. Pre-terminated serial cable is simple, low noise, inexpensive and quick to install, and links the sensor modules to the monitor/manager. Connection in a loop system means that even if the cable is cut, all the sensor modules will still operate correctly.

Does the Vigilant system require to be connected to a computer, a network or the internet in order to function?
No, the Vigilant BMS is designed to be an autonomous system and does not require any external connections in order to function. It will scan, store and interpret data for the life of the system, even if never connected to any computer or network. Of course, a computer can be connected directly for viewing the data in a web browser if needed. And if required, the two volt-free relay contacts can be used as its only connection to any external system.


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