REC Active BMS

We are proud to announce our new product REC Active BMS for 4 cells connected in series with active bi-directional balancing. Long-term development now enables us to present you this excellent device, proven with various real life test conditions, latest technology of electronics components and unbeatable balancing algorithms. Also compatible with Victron Energy inverters and Wakespeed WS500 regulators for use in marine applications.



  • Li-PO, LiFePO4, LiFeYPO4, LiCoO2, LiMnNiCo and LiMnO4 Lithium-Ion chemistry
  • suitable for 4 in-series connected cells per unit
  • high efficiency 2 A bi-directional active balancing (pack to cell and cell to pack)
  • IP65 protection enclosure, AMP 35 pin water resistant connector
  • 2 – 5 V measuring range, 2 mV accuracy
  • up to 2 digital temperature sensors
  • shunt current measurement
  • robust and small design
  • galvanically isolated RS-485 and CAN communication protocol
  • two programmable fused relay output
  • two programmable fused digital output
  • ON/OFF switch
  • LED and buzzer status indication
  • equipped with bootloader for remote firmware update
  • error LED + buzzer indicator
  • PC user interface for changing settings, data-logging and firmware update
  • compatible with REC LCD touch display and Wi-Fi module for monitoring
  • compatible with Victron inverters for solar applications
  • compatible with Wakespeed regulators for marine applications


  • low power microcontroller RTC
  • custom made software with bootloader for remote firmware update
  • 60 mW self power consumption with disabled CAN and all outputs

RS - 485 Communication:

  • galvanically isolated RS-485 communication
  • Slave configuration
  • RS-485 driver primary side supply is activated with Master connection to save energy consumption
  • fully compatible with REC LCD touch display and Wi-Fi module for monitoring

Active Balancing:

  • 2A cell equalizing with active balancing with synchronous flyback bi-directional energy transfer: cell to pack and pack to cell
  • top side and bottom side balancing prolong the cycle duration due to the weakest cell


  • two fused relay outputs with NO and NC pins
  • two fused galvanically isolated/non-isolated digital outputs with PWM option

Galvanically Isolated CAN:

  • galvanically isolated CAN
  • 100, 125, 250, 500, 1 MHz bit-rate selection
  • message programming
  • disable option

Complete Wiring of ABMS Connector:

  • 5 cells wires (l = 1 m)
  • relays, digital output wires (l = 0.5 m)
  • RS485 cable (l = 0.5 m)
  • CAN cable (l = 0.5 m)
  • remote ON/OFF switch (l = 1 m)
  • temperature sensor (l = 1 m)
  • cable for current sensor shunt (l = 1 m)


  • width with mounting pads = 135 mm
  • width = 105 mm
  • length with connector = 111 mm
  • length = 104 mm
  • height = 44 mm
  • connector width = 59.5 mm
  • hole diameter = 4.5 mm
We suggest M4 screws for mounting.