SmallBMS V2

The smallBMS V2 is an all-in-one battery management system (BMS) designed specifically for Victron Energy Lithium Battery Smart batteries. It is a simple and cost-effective alternative to the VE.Bus BMS, but without the VE.Bus interface.

The smallBMS V2 integrates several key features for managing your installation:

A load disconnect output to control equipment.
A pre-alarm output to warn of low battery voltage.
A charge disconnect output to manage chargers.
A remote on/off switch to control the disconnect outputs simultaneously.
Two LED indicators for system status.

The smallBMS V2 provides essential protection against undervoltage and overvoltage of cells, as well as against extreme temperatures (high and low) for Victron Energy Lithium Battery Smart batteries.

The smallBMS V2 has dimensions of 106 x 42 x 23 mm (height x width x depth) and weighs 0.1 kg.

The smallBMS V2 is designed to operate within an ambient temperature range of -20 to +50 °C.

The current consumption of the smallBMS V2 is 2.2 mA when the remote function is enabled (excluding load disconnect and load disconnect output current). When the cell voltage is low or the remote function is disabled, consumption drops to 1.2 mA.

Yes, the smallBMS V2 is equipped with two LED indicators:

A blue LED (Load ON) indicating that the load disconnect output is active (cell voltage above 2.8V by default). A red LED (Temp or OVP) indicating that the load disconnect output is inactive due to a cell temperature that is too high or too low, or a cell overvoltage.

The smallBMS V2 has an IP20 protection rating, meaning it is protected against solid objects larger than 12.5 mm but not protected against water.

The smallBMS V2 is compatible with Victron Energy Lithium Battery Smart batteries, which are Lithium Iron Phosphate (LiFePO4) batteries available in 12.8 V or 25.6 V.

Yes, compatible batteries can be connected in series, parallel, or series/parallel to build a battery bank suited to 12 V, 24 V, or 48 V system voltages.

The smallBMS V2 can manage a maximum of 20 batteries in the same system, allowing energy storage capacity up to 84 kWh in a 12 V system and up to 102 kWh in 24 V or 48 V systems.

No, the smallBMS V2 does not have a VE.Bus interface and is therefore not compatible with Victron Energy VE.Bus MultiPlus and Quattro inverters/chargers.

Yes, the load disconnect output can control remote on/off inputs of devices such as BatteryProtect, inverters, and DC-DC converters. The charge disconnect output can control remote on/off ports for chargers like the Smart Charger IP43, Cyrix-Li-Charge relays, or Cyrix-Li-ct combiners.

The load disconnect output is normally "high" (equal to the battery voltage) and becomes "floating" (open circuit) when cell undervoltage is imminent. It can be used to remotely control the on/off input of loads, with a maximum output current of 1 A.

The charge disconnect output is normally "high" (equal to battery voltage) and switches to an open circuit state in case of imminent cell overvoltage or low/high temperature. It is used to remotely control the on/off port of a charger, with a maximum current of 10 mA. This output is not suitable for inductive loads.

The pre-alarm output can be used to trigger a visible or audible warning when battery voltage is low. It activates at least 30 seconds before the load-disconnect output is disabled due to cell undervoltage. It is normally floating and goes high when cell undervoltage is imminent (default: 3.1V/cell). Maximum output current is 1 A.

The remote on/off switch allows simultaneous control of both load disconnect and charger disconnect outputs. It features two terminals: Remote L and Remote H. A switch or relay contact can be connected between L and H. Alternatively, terminal H can be connected to the battery positive, or terminal L to the battery negative. When the function is disabled, both outputs become floating, shutting off loads and chargers.

Yes, it is mandatory to install either an on/off switch between the L and H terminals of the remote on/off terminal, or the wire loop (default) for correct operation of the smallBMS V2.

Installation must be performed by qualified and trained installers, in compliance with national safety regulations. It is crucial to carefully review the manuals of all connected devices, to power off the system before any modifications, not to open the lithium battery, to charge it only within the specified limits, and not to discharge it before a first full charge.

When multiple batteries are connected in parallel and/or series, the two sets of M8 circular connector cables from each battery must be connected in series (in a "daisy chain"). The two remaining cables must then be connected to the BMS. It is essential to follow the installation instructions in the Lithium Smart battery manual.