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The Current Control Unit (CCU) with outside ancillaries monitors and controls the installation’s battery pack. The batteries’ capacity will differ from one cell to another, these deviances will increase with number of charging/discharging cycles and in due course lead to trouble. The CCC unit contains necessary parts to protect the system and accessory to improve and to make readings possible.

Temperature Sensor

Digital Temperature Sensors are monitoring the battery pack’s temperature, the BMS will act when a certain temperature has been reached and react as over-temperature protection. Temperature with battery current and cell’s voltage are used to compute the determined State of Charge (SOC) State of health (SOH) is determined by comparing cell’s current parameter with the parameters of the new battery pack

BMS Current Measurement

A shunt resistor with a 4 leads Kelvin connection and a shielded cable are used to measure the current and to transfer the infor- mation to the BMS. The battery pack current is measured every second with high precision, ADC is used to filter out current spikes. The first current measurement is timed at the beginning of the cell measurement procedure for a proper internal DC resistance calculation.

Imansson CCU, current control unit


Battery Management System (BMS)
Pre-Charge unit(s)
Temperature Sensors
Contactor Relay(s)

Current Shunt(s)
Relay Block
Thermal Switch
Circulation Pump

Battery Management Pack

The BMS equalizes battery cell’s voltages by diverting some of the charging current from higher voltage cells; named passive balancing.

The BMS unit’s temperature is measured to protect the circuit from over- heating due to passive balancing.

Liquid cooling is used to keep the temperature down, coolant is circulating through the back-plate and heat exchanger. Thermal switches control the pump’s engagement to reduce current consumption.


  • Single cell voltage measurement (01-5.0V)
  • Single cell under/over voltage protection
  • Single cell internal resistance measurement
  • SOC and SOH calculation
  • 12Volt galvanically isolated supply (10.5-15V)
  • Over and under temperature protection
  • Passive cell balancing up to 0.9A per cell
  • Shunt current measurement (resolution 19.5mA@±500A)
  • Programmed relay (NO)
  • Galvanically isolated RS-485 communication protocol
  • Can communication
  • BMS shutdown @ 0.98 x minimum cell disconnect threshold

Pre-charge Unit

The Pre-charge unit eliminates high inrush currents by charging the input capacitor before the main contactor switches on, prolonging lifespan of the contactor and other components exceedingly.


  • Low power consumption @ 11-68VDC
  • Adjustable delay (2-4-8-12 sec.)
  • Integrated 66Ω power resistor
  • 2A open collector contactor coil drive
  • Reverse polarity protection
  • Over voltage protection
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