The Wattius wBMS-R24 is a compact Battery Management System developed to work with up to 24-cell lithium batteries while safely providing extended isolated interface possibilities. The system has been designed to meet all relevant industry requirements such as IEC61508.

This system can monitor and balance up to 24 cells in series with total maximum voltage measurement error of ± 1,5 mV for the entire range. It features state-of-the-art low power mode as well as integrated hardware and software diagnostics.

Multiple wBMS-R24 units can be connected in parallel without additional hardware. The system automatically handles string connection and provides a single control interface with the inverter / charger.

The wBMS-R24 protects the battery by driving up to 6 power contactors, calculates advanced parameters such as SoC and SoH and features multiple interface possibilities such as CAN bus, Bluetooth, and USB.

  • CANbus, Bluetooth & USB.

  • Real-Time logging of events, alarms and operation data to microSD card.

  • Monitoring, configuration & analysis with free wBMS-Toolkit PC software.

  • Up to 24 cell measurement with ± 1,5 mV max. error.
  • Ultra low power mode (< 15 mW).
  • High-precision SoC algorithm.
  • Up to 300mA autonomous balancing.
  • EMC CE Class A & B compatible.
  • IEC61508 compatible design and components.
  • Internal diagnostics and safety-critical redundant systems.
  • Cell and relay open-wire detection.
Power Supply

10 – 36 Vdc

< 15 mW in deep sleep mode

Independent input for output supply

Cell measurements

(voltage & temperature)

Multiple cell chemistry and supercapacitors.

Extended internal redundancy and hardware integrity diagnostics.

Open wire detection.

Cell voltage

5 – 24 cells. 0 – 5 Vdc.

± 1,5 mV cell voltage max total error.

Cell temperature

Up to 6 channels. Configurable NTC 10 kΩ.

± 1 ºC cell temperature max total error.

BalancingAutonomous. Configurable. Up to 300 mA per channel.
Current sensingExternal 0 – 5 Vdc hall current sensor. < ± 0,1 mV.
CAN Interface

CAN bus 2.0 A/B (Up to 1Mb/s). Referenced to external power supply.

Configurable termination resistor with switch.

Other interfaces

Mini USB 2.0

Bluetooth 5.0 Low Energy.

General Input

2x analog / digital (configurable) signal up to 36 Vdc.

4x dry contact digital input.

Configurable to multiple functions (ignition key, HVIL, relay feedback etc.).

General Output

6x independent channels.
External supply voltage. Maximum total output 4 A. External fuse recommended.

Channel 1-4: 2 A nominal, 4 A peak per channel.

Channel 5-6: 1 A nominal, 2 A peak per channel.

Adjustable PWM @ 10 kHz max.

Open circuit, short-to-battery and short-to-ground detection.


Integrated redundant EEPROM to store system configuration and maximeter.

MicroSD support (up to 32 GB). MicroSDHC Class 10 is recommended.

Operating temperature range-40 to +85 ºC

Up to 16 devices in parallel without external hardware.

Dimensions70 x 150 mm

All wBMS models are compatible with the same wBMS-Toolkit, a free PC software that provides real-time monitoring of all BMS measurements, as well as configuration of thousands of parameters in a flexible and intuitive way.

Connection between wBMS-Toolkit and the devices can be established through USB, CAN bus, Ethernet or even Bluetooth.