Battery Management System (BMS)

The core of every battery is the battery management system, it monitors the battery and ensures ideal and safe operation of the battery system.

The battery management system is the brain of the battery, so to speak. It monitors the condition of the battery and ensures efficient operation and a long service life via cell balancing.

Core competencies of the Futavis BMS: Safe, efficient, durable and flexible


  • Ensuring the ideal operation of the battery
  • Protection against incorrect use and thus avoidance of permanent damage to the battery
  • Application of different safety mechanisms according to ASIL C: such as redundancies, regular communication checks
  • Certified functional safety according to ISO26262, EN ISO 13849, EN ISO 62061, EN IEC 60730


  • Low consumption of BMS components (ultra low power mode for CSC ports)
  • Fast communication and thus fast responsiveness of the control system
  • SOH and SOC monitoring


  • Ensuring operation in the ideal load range (battery level)
  • Passive cell balancing
  • Control of shutdown scenarios in the event of faults such as overtemperature or overvoltage
  • Use of high quality components
  • Remote diagnostics for full insight at any time via UDS diagnostics using CAN


  • Modular structure of the BMS
  • Any Li-ion cell chemistry can be used
  • Individual setting of several parameters of the Futavis BMS
  • Multi-string setup with up to 20 masters individually switchable
  • Communication via CAN as standard, others possible on request

Futavis manages to make your battery efficient, durable and reliable with integrated circuits and a modular design of the BMS. From engineer to engineer, we are on hand to provide advice and support throughout the development process.

Architecture & Features

The BMS controls the cell voltage, preventing over- or undervoltage. This prevents overcharging or complete discharge of the battery. Both scenarios would damage the battery and shorten your life.

Furthermore, it monitors cell temperatures to prevent overheating or undercooling during charging and discharging.

Via a data bus with the end system, the BMS can pass on recorded and stored data and issue corresponding error messages in the event of faults.

The Futavis BMS is based on a master-slave architecture. Whereby the master board represents the superior control unit of the battery.

The CSC boards are used to monitor and balance the cell voltages of individual series connections of cells, in one or more battery modules.

Depending on the size of the battery, the number of masters and CSC boards used varies. Up to 14 CSC’s can be flexibly interconnected. Using the supported multi-master architecture, up to 20 masters can then be combined serially or in parallel to form a scalable system.

For additional monitoring of the insulation resistance, our IsoMonitor can be added to the system. The Futavis S-Box provides the required periphery with regard to the sensors and actuators of the BMS.

Together, BMS, S-Box and IsoMonitor can map all tasks to ensure the functional safety of the battery.


  • Interface to the Futavis IsoMonitor
  • Interface to the Futavis S-Box
  • CAN communication (incl. UDS protocol), other interfaces possible on request
  • With two interfaces for customer-specific functions such as a heating controller

Functions of the Futavis BMS:

  • Coverage of safety targets such as overcurrent, -temperature, -voltage; undertemperature, -voltage, HV interlock with risk classifications up to ASIL C, PL c and SIL 1 respectively
  • Implementation of shutdown processes for active separation of loads
  • Variable control of charge states
  • Passive cell balancing
  • SOC/SOH determination
  • Implementation of derating curves
  • Support of serial and parallel string interconnections of up to 14 cells and 15 CSC’s
  • Communication monitoring
  • Storage of the number of cycles, fault history, critical contactor cycles and current voltage profiles
  • Remote diagnostics for full insight at any time via UDS diagnostics using CAN

BMS Master

The master is the higher-level control unit of the battery. It includes processing of signals, measurements, communication and control interfaces. One master can control up to 15 CSC boards.

The master is responsible for monitoring and controlling the entire battery system, as well as communicating with the other masters, CSC's and other components of the end system. It determines the battery State of Charge (SOC) and State of Health (SOH), and also monitors cell voltages, currents and temperatures, ensuring safe battery operation. Thus, the shutdown in case of over- or undervoltage, over- or undertemperature can be controlled, the balancing can be implemented and all measured parameters can be stored and processed.

A special feature of our Master is that in a multi-string setup no further Master is needed as Master-Master. One of the masters already present in the system can take over all the functions of the system master. Read more here.

The master uses input signals such as Enable, HV Enable, Charge Enable. HV Interlock. Furthermore, the master provides some additional unused GPIOs for user-defined functionalities.


  • Communication between master and CSC/ Isomonitor/ S-Box and masters among each other
  • Evaluation of cell voltage and cell temperature
  • Current measurement by means of Hall sensor
  • HV Interlock
  • On-board temperature measurement

Communication & Interfaces:

  • Available interfaces for customer specific applications
  • CAN interface
  • Plug


  • Functional safety according to ISO 26262, EN ISO 13849, EN ISO 62061, EN IEC 60730
  • Coverage of safety targets such as overcurrent, -temperature, -voltage; undertemperature, -voltage, HV interlock with risk classifications up to ASIL C, PL c and SIL 1 respectively
  • LV124 LV 123
  • ECE R100

Technical data:

  • Processor - ARM Cortex - R4F - 160MHz
  • On-board temperature measurement
  • 2 current measurements (up to 1.5kA), measurement by means of LEM-DHAB series
  • CAN current sensors
  • 3 voltage measurements (up to 1000V)
  • Up to 6 relay drivers (up to 3 A per driver)
  • External watchdog
  • Power supply 8 V ... 36 V
  • Low power consumption of 3.2 W
  • GPIOs:
    • Enable, HV Enable, Charge Enable
    • ID allocation, HV Interlock
    • Costum-defined
  • 2 separate CAN interfaces

BMS CSC (Cell Supervision Circuit)

The "Cell Supervison Circuit" CSC board is responsible for monitoring the temperature and cell voltage. One CSC board is used per battery module, which usually consists of 7-14 cells. The CSC can provide interfaces and passive balancing for all cells. In addition, each CSC board contains up to six (NTC) temperature sensors.

Since the cells are usually not 100% equally charged, the CSC measures the cell voltages and compensates for the differences by additionally discharging the stronger cells.

The connection between the CSC's and between the first CSC and the master is realized by means of High Speed Differential Isolated Communication.


  • Monitoring of short circuits and contact breaks
  • Voltage monitoring up to 14 cell voltages (minimum 7 cell voltages) from 2 - 5 volts
  • Passive balancing of each cell
  • Module voltage measurement
  • Cell temperature monitoring with up to 6 NTC temperature sensors ( T-ranges?)
  • PCB ambient temperature measurement
  • Two versions for temperature sensor inputs:
    SD12T4K10NXPCMQS26 (10k NTC) & SD12T4K100NXPCMQS26 (100k NTC)
  • AFE: NXP MC33771B

Communication & Interfaces:

  • Transmission of measured values via Highspeed Differential Isolated Communication
  • Plug


  • Functional safety according to ISO 26262, EN ISO 13849, EN ISO 62061, EN IEC 60730, ASIL C
  • LV124 & LV 123
  • ECE R100


  • All cell chemistries usable
  • 6-14 cells per module
  • 2-5 Volt
  • Modular software architecture
  • Low power consumption of 1,065.50 mW (2.89 mW in sleep mode)

Modular software construction kit

The Futavis BMS is based on a modular development approach. Starting with the self-developed software and hardware up to automated testing, the Futavis BMS can be quickly and efficiently integrated into the individual customer system.

Comming soon....