Victron Energy SmallBMS for Smart LiFePO4 Batteries with M8 - Battery Management System

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 a compact and cost-effective battery management system designed specifically for use with Victron Smart LiFePO4 batteries equipped with M8 circular connectors. This BMS offers essential protection and control features that make it an excellent replacement for the VE.Bus BMS in various applications, excluding use with VE.Bus MultiPlus and Quattro inverter/chargers due to the lack of a VE.Bus interface. Its straightforward design simplifies system integration while ensuring reliable battery operation.
Constructed to operate within a voltage range of 8 to 70V DC, the SmallBMS provides three key outputs for monitoring and controlling your battery system. The Load Disconnect output, which is normally high, can be used to operate high-current relays or contactors, or to control remote on/off inputs of various loads such as inverters or DC-DC converters. This output becomes free-floating if a cell voltage drops below the default threshold of 2.8V per cell (adjustable between 2.6V and 2.8V), providing a safeguard against deep discharges. The maximum current for this output is 1A, and it is not short-circuit protected.
The pre-alarm output indicates an imminent under-voltage situation, becoming high when cell voltage drops below a preset threshold of 3.1V per cell (adjustable between 2.85V and 3.15V). This provides a 30-second minimum delay before load disconnect, giving users time to react to potential issues. The Charger Disconnect output, which is normally high, can control remote on/off functions of chargers, battery relays, or battery combiners like the Cyrix-Li-Charge and Cyrix-Li-ct, and becomes free-floating in case of overvoltage or over-temperature conditions. It has a maximum current capacity of 10mA and is not suitable for inductive loads.
The system on/off input allows for centralized control of the entire system, managing both load and charge outputs. When switched off, both outputs become free-floating, effectively turning off connected loads and chargers. The input utilizes two terminals, Remote L and Remote H, which can be connected via a switch or relay contact, or directly to battery terminals. LED indicators display system status: a blue LED shows when the load output is high (cell voltage above 2.8V), and a red LED signals over-temperature, over-voltage, or under-temperature conditions. This BMS ensures robust protection for 12V, 24V, and 48V systems, making it versatile for various battery configurations. Overall, the Victron SmallBMS provides reliable, essential management features for maintaining battery health and safety in your energy system, all within a compact and easy-to-install package.

Features:

• Designed for Victron Smart LiFePO4 batteries with M8 connectors

• Operating voltage range from 8V to 70V DC for versatile system compatibility

• Load Disconnect output: controls high-current relays or contactors, adjustable under-voltage threshold

• Pre-alarm output: signals imminent under-voltage with adjustable threshold and minimum delay

• Charge disconnect output: manages remote charger on/off, responds to overvoltage and over-temperature

• System on/off input: centralized control via remote switch or relay contact

• LED indicators: blue for load active, red for overvoltage/temperature alerts

• Compact and lightweight design suitable for various battery configurations

• Reliable protection for 12V, 24V, and 48V battery systems

• Easy integration with existing battery management and energy systems