The EMUS BMS Mini 3 is a compact all-in-one battery management system that monitors and protects 6 to 16 lithium battery cells connected in series. Integrating MOSFET-based charge and discharge contactors, a pre-charge circuit, onboard current sensors, and multi-protocol communication interfaces, it provides complete autonomous battery management for light electric vehicles, mobile robots, and portable energy storage systems.

How does the integrated contactor and pre-charge system work?

Unlike traditional BMS designs that require external contactors and a separate pre-charge relay, the BMS Mini 3 embeds MOSFET switches directly on the board. The pre-charge circuit limits inrush current to the motor controller's DC-link capacitors during connection, preventing contact welding and extending component life. When a charger or load is connected, the BMS first closes the pre-charge path through a 39 Ω resistor, monitors the voltage equalization, and only then engages the main MOSFET — all within milliseconds. Continuous discharge current is rated at 90 A standalone or 150 A with an auxiliary heatsink, with 10-second peak ratings of 220 A and 300 A respectively.

What communication and data logging options does it offer?

The BMS Mini 3 transmits real-time cell voltages, temperatures, state of charge (SOC), and state of health (SOH) via CAN bus (up to 1 Mbit/s), USB, RS485, and Bluetooth — enabling direct connection to vehicle control units, charger CAN interfaces, and the EMUS EVGUI mobile app. An onboard SD card slot logs all measurement data for post-operation diagnostics and warranty tracking. The system supports master/slave networking via CAN for multi-pack installations, and five general-purpose I/O pins accept external sensors or drive indicator outputs. Advanced SOC estimation combines Coulomb counting with cell degradation tracking (SOH), supporting both CAN-managed chargers (Elcon, Zivan, Delta-Q, Powerfinn) and non-CAN charger control via I/O.