Frequently Asked Questions:

Which EMUS BMS system to choose?

  • 1. Which EMUS system to choose for my battery system?

    There are different types of EMUS BMS configurations, which should be chosen according to the application’s and

    battery system’s requirements. EMUS can fit practically all the most common battery systems topologies used worldwide, that’s why we claim EMUS as the most modular system in BMS industry. Let’s see what is available and how it differs.

    • BMS Mini: all-in-one unit for a single battery pack of 6-16 cells in series (battery pack voltage 12.0 V – 72.8 V), with MOSFET switches, integrated pre-charge circuitry, and two current sensors. Connectivity to PC via USB port, wireless smartphone connectivity with an EMUS App, 500mA passive balancing, CAN communication, 100A continuous charge/discharge current (peak 250A). See Datasheet for more details Mini 3 Datasheet

    • G1 Distributed Regular: For simple cases, when battery cells are connected in series as one battery pack (max. 40-60 cells in series), usually used for prismatic cells or paralleled cylindrical groups.
      Voltage range 12V – ~240V, discharge current up to ~1000A, or 2500A with Isabellenhuette IVT-S series current sensor.


    • G1 Distributed Grouped: Battery cells are grouped into blocks (recommended up to 60 cells in series per block) and each block is connected with CAN Cell Group Modules (CGM unit). Then all (recommended max. 24) CGM units (or 24 packs) are connected via CANbus line to Control Unit.
      Voltage range 12V – ~1300V, discharge current up to ~1000A, or 2500A with Isabellenhuette IVT-S series current sensor.


    • G1 CCGM Centralized: for applications when batteries are split into separate blocks up to 16 cells connected in series or/and parallel (recommended max. 24 CCGM units in total), recommended for cells with capacities up to ~100Ah.
      Voltage range 12V – ~1300V, discharge current up to ~1000A, or 2500A with Isabellenhuette IVT-S series current sensor.


    • G1 Distributed Master-Slave: EMUS G1 Master-Slave BMS topology is used to build large Lithium-ion battery systems mostly in electric energy storage (EES) applications where high power, capacity, and modularity are required. Such BMS configuration not only allows to build large ESS system, but also provides redundancy features, for example, if one of the battery strings/subsystems runs out of operation, other battery strings can operate and provide power continuously. Up to 6MWh power energy storage systems can be built with off-the-shelf products and larger systems can be made with customized solutions.


    EMUS G1 Master-Slave system is a combination of several commonly used EMUS G1 Distributed Grouped or Centralized CCGM subsystems. Simply said, up to 18 strings, with each string having its own G1 Control Unit can be interconnected into one large system. From all of the 18 Control Units, one of them is automatically designated as a „Master CU“ and the remaining Control units as „Slave CU“.  In such a way „Master CU“ is gathering information from „Slave CU“ strings and commands operational logic, as well communicates with external devices such as chargers, inverters, VCU, PLC, etc. All system configuration is easily made on EMUS Control Panel, which is provided free of charge to EMUS customers.

    This system runs on EMUS proprietary CAN communication protocol using a special item for efficient CAN traffic distribution called „CAN filter“. CAN filter is filtering internal system‘s CAN traffic from external CAN traffic, thus making it stable and reliable.

  • Installation and operation

  • 2. With which OS does EMUS Control Panel work?

    EMUS Control Panel works only with Microsoft Windows OS. However, there is an EMUS App, which allows to see main system’s parameters. To access EMUS App with G1 system, Smartphone connectivity module must be purchased.

  • 3. Which communication types does EMUS Control Unit supports?

    EMUS G1 Control Unit supports serial (RS232/USB) and CAN communication.

  • 4. Which chargers, inverters are supported by EMUS G1 system (Control Unit)?

    List of supported chargers can be found below (in EMUS G1 User manual, page 46):

  • 5. Which charges does the EMUS BMS Mini 3 supports?

    EMUS Mini 3 supports the following chargers:

    Most recent information can be found on Mini 3 Datasheet.

  • 6. When using CAN based charger, which pins should be mapped?

    When using a CAN-based charger is controlled by sending the requested output voltage, current values, and other parameters in a CAN message using the charger-specific protocol. In this case, the pin “PF10 Charger Enable Output” pin function is used.

  • 7. When using a non-CAN-based charger, which pins should be mapped?

    Non-CAN chargers can be only controlled by switching them on and off as they do not have remote output current and voltage adjustment. In this case, the “PF10 Charger Enable Output” pin function should be used. Additionally, Control Unit acknowledges the connection and disconnection of such charging device whenever a corresponding high/low signal is detected on a general-purpose input pin mapped with the “PF3 Charger Mains AC Sense Input” function.

  • 8. When using analog based charger, which pins should be mapped?

    These chargers are controlled by a corresponding PWM signal generated on the “SOC OUT” pin of the Control Unit which has to be mapped with the “PF18 Analog Charger Control Output” pin function. The role of the “PF10 Charger Enable Output” pin function when using an analog signal-controlled charger is identical to when a CAN charger is used, while the connection and disconnection are acknowledged the same way as for the non-CAN charging devices with “PF3 Charger Mains AC Sense Input”.

  • 9. How many cells can I connect to EMUS BMS Mini?

    A minimum of 6 cells and a maximum of 16 cells in series can be connected to EMUS BMS Mini 3.

  • 10. How to connect less than 16 cells in my BMS Mini or Centralized CAN Cell Group Module (CCGM)?

  • 11. Can EMUS G1 Control Unit and EMUS Mini 3 be connected to the same Control Panel version?

    No, both systems have their own Control Panel versions. Control Panel versions for both devices can be found on the following link: https://emusbms.com/manuals-downloads

  • 12. Does the BMS Mini 3 have its own current sensor? What are ‘current 1’ and current 2’ parameters measuring?

    EMUS BMS Mini 3 has a current sensor that measures his own current consumption. In Current 1 sensor measure battery drain current, Current 2 sensor allows to monitor momentary charging current.

  • 13. How does electric current is measured in EMUS BMS Mini 3?

    EMUS BMS Mini 3 has a current sensor that measures its power consumption. It is possible to monitor how much EMUS BMS Mini 3 system drains/charges the battery cells. Current 1 sensor measures the battery drain current and Current 2 measures the momentary charging current. On board, current measurements are used to calculate SOC/SOH.

  • 14. Can EMUS Mini 3 measure its internal temperature? How many external sensors can be connected to it?

    Yes, EMUS BMS Mini 3 can measure his own temperature. Up to 5 external temperature sensors could be connected to EMUS Mini 3.

  • 15. Is it recommended to use a contactor with the EMUS G1 BMS system?

    The main contractor should be installed behind all load devices and its coil terminals should be connected directly between the Control Unit’s power supply positive terminal and one of the general-purpose outputs mapped with “PF12 Battery Contactor Output”.

  • 16. Is it possible to use a 3rd party current sensor with EMUS G1 Control Unit?

    Yes, it is possible to use 3rd party German Isabellenhuette IVT-S series CAN current sensor. If a 3 rd party current sensor is being used, installation depends on sensor type. EMUS provides recommendations, on how to install such current sensors, but if you need more details, you can refer to the datasheet of the specific sensor.

  • 17. Is it necessary to install any fuse in your system?

    In order to protect the battery and the system in which it is used from unpredictable, potentially destructive consequences of contactor failure (e.g. welding), load or charging device failure, short circuit, or other similar cases, it is necessary to install a battery fuse behind the main contactor.

  • 18. Is mandatory to connect DC/DC converter to EMUS G1/Mini 3 Control Unit?

    It is not mandatory, however, in some applications where the grid power is not available all the time (e.g. off-grid energy storage, electric vehicle, etc.) it is recommended. Additionally, to avoid draining the batteries, EMUS Control Unit can disconnect the DC/DC converter automatically by one of its output pins.

  • 19. How to interconnect Cell Modules in EMUS G1 system?

    Procedure to interconnect Cell Modules, can be found in the image below:

    There are not specific settings for different cells and chemistries as the values depend on the cell’s manufacturer and cell specification sheet. However, there are few recommendations to consider when settings these values according to the cell specifications sheet:
    • Fully Charged Voltage = Cell Charge Voltage (not to confuse with charge cut-off voltage).
    • Allowed Disbalance ~ 0.03 V.
    • Early Balancing Threshold < Cell Nominal voltage.
    • Charge Restart Voltage < Cell Nominal voltage.
    • Pre-Charge Threshold = Cell Discharge cut-off voltage.

  • 20. When is BMS entering in Balancing stage?

    BMS is entering in Balancing stage once the maximum cell voltage is equal or higher than the Fully Charged Voltage parameter.

  • 21. How to change dependency of the speed from the frequency in Distance Parameters?

    It depends in the pulses per Distance Unit. For example, if 1000 pulses are set, 1km will be 1000 pulses. As 1Hz is 1m/s, distance will be 3.6Km/h(1Hz).

  • 22. Which devices are supported for the SmartPhone Connectivity Module (SCM030A)?

    • iPhone iOS 9.0 or later.
    • Android 4.4 or later.
    • All Windows OS versions with BLED112 USB dongle.

  • 23. Is it possible to calibrate L and H values when charger is connected?

    No, if charger is connected these values could not be changed. Alternatively, if charger needs to be connected, these values could be calculated manually by the equation on the page 125 of the G1 Control Unit User Manual and being inserted once the charger is disconnected.

  • 24. Is there any Insulation detector recommended to use with EMUS Control Unit?

    Unfortunately, at the moment there is not any Insulation detector recommended for EMUS Control Unit.

  • 25. Which external temperature sensor used CCGM022D?

    CCGM022D supports 10kΩ NTC temperature sensor.

  • 26. Does CAN line have to be terminated?

    According to high-speed transmission specification in ISO11898-2 standard, both ends of the CAN bus must be terminated in order to minimize reflections and ensure that both lines are correctly returned to a recessive state.

  • 27. Is it possible to power devices from EMUS BMS outputs?

    Unfortunately, I/O pins are connected to the ground so it is not possible to power any device from EMUS BMS outputs.

  • 28. What is the usual baud rate for Master Clear Process?

    The usual baud rate for the Master Clear process is 57600.

  • 29. When the BMS MINI 3 is used with a non-CAN charger, is the charge port of the BMS always open, or is there a switch to turn it on and off? If there is a switch, how does it open and close?

    Mini3 non-CAN charger version uses the “PF3 Charger Mains AC Sense Input” pin to determine if the charger is connected. If PF3 input indicated that an AC charger is connected BMS checks if the battery needs charging (e.g. looking at the battery voltage level) then it closes the contactor between C+ and B+ terminals if charging is needed. During the balancing stage at the end of charging, the contactor may be closing and open according to the algorithm to balance the cells. After finishing the charging, the contactor is opened. Also, this contactor is opened whenever a protection event occurs. Note: the PF3 input pin has to be set up through the Control Panel on the GPI pin of your choice.

  • 30. How to select contactor?

    Your system’s charge/discharge current needs to be lower than contactor’s nominal current and voltage of your system needs to be within the working voltage range of the contactor.

  • 31. How is the contactor connected and configured when using a charger/inverter?

    In this case, it is possible to use only one contractor. For this, connection with the battery contactor is done through “PF12 Battery Contactor Output”. “PF10 Charger Enable” is not connected but it should be mapped in configuration to allow charging. Finally, if “Charger Connected” protection is disabled, the same contactor can be used during charging and discharging.

  • 32. What type of connector is needed to connect to the EMUS G1 Control Unit?

    To connect to 22 pins main connector, Molex Micro-Fit 3.0 receptacle 43025-2200 is needed. Meanwhile, for 8 pin connector, Molex Micro-fit 3.0 receptable 43025-0800 is needed.

  • 33. What is the difference between User State of Charge and State of Charge?

    With User State of Charge, you can set a range of usable real SOC. To set this range you need to go to Control Panel -> Configuration -> SOC/SOH -> User SOC config Parameters.

    When the real value for the SoC is lower than ‘0% User SoC from Real SOC’ parameter, user SOC will be considered as 0%. Meanwhile if the real value for the SOC is higher than ‘100% User SoC from Real SOC’ value, then user SoC will be considered as 100%.

    As Control Unit sends User SoC value, usable capacity will be limited, helping to extend battery life by setting the range in which the battery can be operated.

  • 34. Is it possible to use Smartphone Connectivity module and Display Unit at the same time?

    Unfortunately, it is not possible to use Smartphone Connectivity module and Display Unit at the same time.

  • 35. How to know a firmware image is being updated to your device?

    When firmware process is started, you should see the ‘boot’ text displayed inside the ‘Firmware version field. It means that device firmware is indeed being updated.

  • 36. How many display modes have the Display Unit have?

    Display Unit has two display modes:
    • Electric Vehicle: It contains layouts related to consumption and speed information.
    • Energy storage: This mode focuses on displaying detailed information about the system.

  • 37. Can statistics and events be cleared from the Control Panel?

    Events and some statistics can be cleared from the Control Panel by clicking on the ‘Clear statistics’ and ‘Clear Events’ options. Statistics with the ‘*’ symbol cannot be cleared.

  • 38. Which length is recommended for data communication cable?

    Recommended cable (data and power) length between cell modules is less than 10cm. If longer cables are used, please follow these recommendations (polarity and UP/DOWN cable directions mentioned are about that cell module):
    • Power positive and data cables should not be routed next to each other in parallel. If this is unavoidable, the power positive and UP data cables (coming from the cell module) could be routed together in one current direction; the DN cable (coming into the cell module) then has to be routed further away, although this is still not recommended.
    • To reduce any possible noise coming from power cables shielded cables can be used for data. Only the DN end of the shield has to be connected to the CGM’s negative terminal.

  • 39. Which conditions need to be met for balancing stage to finish?

    The “Balancing stage” is over if at the moment when the charging current drops below “Charging Finished Current” parameter value the max cell voltage is equal to “Fully Charged Voltage” parameter value, the difference between minimum and maximum cell voltages is less than the value of “Allowed Disbalance” parameter, and minimum balancing rate is more than a half of maximum balancing rate.

  • 40. How to configure CGMs manually?

    To manually configure CGMs, you need to open your Control Panel and go to Configuration -> CGMs Map. There you need to specify the total number of CGMs in your system and the number of parallel strings. Select correct CGM type. And fill the table with the number of cell connected to each CGM, the string ID for that CGM (first string ID = 0) and the serial number of the CGM which you can find written on it. Then you can commit configuration for each CGM.

  • 41. How to connect CGM system?

    CGM system must be connected starting by connecting the green communication wire of the bottom cell communication adapter to the “DN” input of the first Cell Module. Then the wiring process should be continued by successively connecting the “UP” output of each Cell Module to the “DN” input of the next Cell Module and finished by connecting the green communication wire of the top cell communication adapter to the “UP” output of the last Cell Module.

    CGM system must be connected starting by connecting the green communication wire of the bottom cell communication adapter to the “DN” input of the first Cell Module. Then the wiring process should be continued by successively connecting the “UP” output of each Cell Module to the “DN” input of the next Cell Module and finished by connecting the green communication wire of the top cell communication adapter to the “UP” output of the last Cell Module.

  • 42. What is the maximum value for maximum balancing current when using CCGMs?

    The maximum value for maximum balancing current is 100%, however, it is only possible to set it in intervals of 10% due to different approaches to cell balancing.

  • 43. When is the “number of chargers” parameter appearing?

    The “Number of chargers” parameter is appearing only when the Control Unit is uploaded with a firmware that supports a parallel CAN charger.

  • 44. What does the “invert” button on the Control Panel I/O pins window?

    The “invert” button determines which logic level corresponds to the active state of the signal. However, there is an exception for EMUS G1 Control Unit speed sensor input (SPEED IN), if it is mapped with its default function, the “invert” parameter changes which edge is used to count the pulses of the speed signal. If not inverted on the rising edge if inverted on the falling edge. Otherwise, the meaning is the same as for general-purpose inputs.

  • 45. Are all the firmware images from the same version equal?

    No, there are few firmware images with the same version, but they differ in supported charger type.

  • 46. Is there any UI written program to get reports and control EMUS G1 Control Unit?

    We currently do not offer any SDK or ready to use interfaces. Communication requests are done through Serial or CAN interfaces as per described protocol. Find serial and CAN protocols in our website https://emusbms.com/manuals-downloads

  • 47. Does the USB FTDI arrive with the starting kit?

    USB FTDI is already integrated in EMUS G1 Control Unit. There is no need of additional hardware, only an USB cable.

  • 48. Can I use top/bottom isolators in parallel?

    No, top/bottom isolators are not designed to be used with parallel-connected cells. Top/bottom isolators can support from 4 up to 80 series-connected cells.

  • 49. How to load new configuration file to EMUS Control Unit?

    To load a new configuration file to your Control Unit, you need to open the Control Panel, go to Configuration window, Management tab, and press “Load…” button in configuration. Then select the configuration file you need to upload, press open, and wait until upload is finished.

  • 50. Is it possible to have 3D-models of our products?

    Yes, it is possible. 3D-models of our products. Models can be found in our website:


  • 51. How to save the configuration file of EMUS Control Unit?

    To save your configuration file, you just need to open your Control Panel, go to Configuration, then Management and finally press the ‘Save…’ button. After pressing the ‘Save…’ button you can select file directory where the configuration file will be saved.


  • BMS malfunctioning

  • 52. Points to pay attention when incorrect number of cells error appears.

    • Make sure that Number of Overall Cells is set correctly (Configuration -> General -> Battery pack -> Number of Overall Cells).
    • Make sure that CAN Devices configuration has been committed correctly (Configuration -> CAN Devices).
    • Check cell modules are working properly.

  • 53. Points to pay attention when CAN Devices are not discovered.

    • Check all LEDs are blinking. If one LED is not blinking, issue is on first not blinking Cell Module.
    • Check communication daisy chain is wired correctly. For how to wire it, refer to question 12.
    • Power positive and data cables should not be routed next to each other in parallel.
    • To reduce any possible noise coming from power cables shielded cables can be used for data.
    • Make sure CGM/CCGM connection with cells is properly done. For how to wire it, refer to question 12.
    • Make sure CAN terminators are installed at both ends of your CAN line.
    • Make sure you are using CAN communication in your BMS configuration.
    • Make sure that CAN settings are set correctly.

  • 54. Which conditions can lead to the “Charging Error” stage?

    Different conditions can lead to the “Charging Error” stage. These conditions are:
    • No cell communication.
    • Charging stage duration exceeded.
    • Detected number of cells does not match the “Number of Overall cells” parameter.
    • Protection event occurred.
    • Cell or cell module temperature too high.
    • Cell Over-voltage.

  • 55. Control Panel does not detect COM port where EMUS Control Unit is connected. What to do?

    In this case, it is recommended to install FT232R USB UART DRIVER. Driver and step-by-step instructions can be found in the link below:


  • 56. How to unlock protected by password control unit?

    To delete password from a password protected control unit, Master Clear process would be needed. Please, refer to page 126 of the G1 Control Unit User Manual.

  • 57. How to reset configuration parameters to default values?

    To reset your configuration parameters to default values, you just need to open your Control Panel, go to Configuration, then Management and finally press the ‘Defaults…’ button. After pressing the ‘Defaults…’ button, your parameters will be reset to default values.

  • 58. How to capture logs from the EMUS Control Unit?

    To capture logs from the EMUS Control Unit, you just need to select the option ‘Write Logs’ on the option window of the Control Panel. To save the log file, you can enable the option ‘Active Polling’ and the file will be automatically saved in the Control Panel folder or choose an specific folder on your computer by selecting the option ‘Choose Log File Directory’.

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