Victron Energy SmallBMS for Smart LiFePO4 Batteries with M8 Connectors

SmallBMS for Smart LiFePO4 Batteries with M8

A simple and low-cost alternative to the VE.Bus BMS. The smallBMS can replace the VE.Bus BMS in several applications. It is however not suitable for use with VE.Bus MultiPlus and Quattro inverter/chargers: it has no VE.Bus interface.

The smallBMS is intended for use with Victron Smart LiFePo4 batteries with M8 circular connectors. The smallBMS has three outputs, similar to the VE.Bus BMS. Load Disconnect output The Load output is normally high and becomes free-floating in case of the cell under voltage (default 2,8V/cell, adjustable on the battery between 2,6V and 2,8V per cell). Maximum current: 1A. The Load output is not short-circuit protected.

The Load output can be used to control:

• A high current relay or contactor.


• The remote on/off the input of a Battery Protect, inverter or DC-DC converter, or other loads.

Pre-alarm output

The pre-alarm output is normally free-floating and becomes high in case of the imminent cell under voltage (default 3,1V/cell, adjustable on the battery between 2,85V and 3,15V per cell). Maximum current: 1A (not short circuit protected).

The minimum delay between pre-alarm and load disconnect is 30 seconds.

Charge disconnect output

The Charger output is normally high and becomes free-floating in case of imminent cell overvoltage or over-temperature. Maximum current: 10mA. The Charger output is not suitable to power an inductive load such as a relay coil.

The Charger output can be used to control:

• The remote on/off of a charger


• A Cyrix-Li-Charge relay


• A Cyrix-Li-ct Battery Combiner

System on/off input

The system on/off input controls both outputs. When off, both outputs will be free floating so that loads and chargers are turned off. The System on/off consists of two terminals: Remote L and Remote H. A remote on/off switch or relay contact can be connected between L and H. Alternatively, terminal H can be switched to battery plus, or terminal L can be switched to battery minus.

Protects 12V, 24V and 48V systems

Operating voltage range: 8 to 70V DC.

LED indicators:

• Load ON (blue): Load output high (cell voltage >2.8V, adjustable on the battery).


• Temp or OVP (red): Charger output free floating (due to cell over temperature (>50C), cell under temperature (<5 C) or cell over voltage).

The Victron Energy SmallBMS (Part Number: BMS400100000) is an affordable and straightforward battery management solution designed specifically for Smart LiFePO4 batteries using M8 circular connectors. It offers a cost-effective alternative to the VE.Bus BMS for applications where a simple, reliable monitoring and control system is required. This BMS is suitable for systems within the voltage range of 8 to 70V DC, making it compatible with 12V, 24V, and 48V battery setups. Its compact design provides essential protection features without the complexity of full VE.Bus integration, making it ideal for DIY setups and smaller energy systems.

The SmallBMS features three key outputs that allow you to control and monitor your battery system effectively. The Load Disconnect output is normally high and switches to a floating state if a cell under voltage occurs (default 2.8V per cell, adjustable between 2.6V and 2.8V). It supports a maximum current of 1A and can control relays or contactors to disconnect loads in case of undervoltage conditions. The Pre-Alarm output signals imminent under voltage at approximately 3.1V per cell (adjustable between 2.85V and 3.15V), providing a warning to prevent damage. It can handle up to 1A of current but is not short-circuit protected.

The Charger Disconnect output protects against overvoltage and over-temperature conditions, becoming floating when such conditions are detected. It supports a maximum current of 10mA and is suitable for controlling remote on/off functions of chargers, Cyrix-Li-Charge relays, or Cyrix-Li-ct Battery Combiners. The System On/Off input allows remote control of both load and charge outputs through a switch or relay contact, enabling complete system shutdown when necessary. The system supports various configurations by connecting Remote L and Remote H terminals, offering flexibility for different installation setups.

Designed for versatile applications, the SmallBMS includes LED indicators for Load Activation and Overvoltage/Overtemperature conditions, providing clear visual status updates. It is built to protect your battery system from common issues such as undervoltage, overvoltage, and temperature extremes, ensuring longevity and safety. Its compact size, lightweight design, and straightforward connectivity make it an excellent choice for DIY enthusiasts and professional installers aiming for reliable battery management without the need for complex communication interfaces. For support, repairs, or returns, please contact your authorized dealer to ensure proper handling of your Victron SmallBMS setup.

Features:

• Compatible with 12V, 24V, and 48V systems operating between 8V and 70V DC

• Load Disconnect output: Normally high, switches to floating on undervoltage (default 2.8V per cell, adjustable)

• Pre-Alarm output: Signals imminent undervoltage (default 3.1V per cell, adjustable)

• Charge Disconnect output: Protects against overvoltage and overtemperature conditions, supporting remote charger control

• System on/off input: Allows remote control of entire system status via switch or relay contact

• LED indicators: Visual status for load activity and system protection alerts

• Compact and lightweight design suitable for various battery configurations

• Simple wiring with M8 circular connectors for easy installation