smallBMS NG for small applications with Victron Smart Lithium NG batteries

The SmallBMS NG is an all-in-one battery management system (BMS) designed for Victron Lithium NG batteries (not compatible with Lithium Smart batteries). It monitors and protects the batteries by managing charge and load cut-offs and triggering low battery voltage pre-alarms.


The SmallBMS NG is a straightforward and cost-effective alternative to the VE.Bus BMS NG for applications that do not require integration with Victron inverters/chargers. It provides essential protection for lithium batteries without the added complexity of the VE.Bus-Kommunikation and is therefore not suitable for use with VE.Bus-Wechselrichtern/Ladegertions such as MultiPlus, Quattro and EasySolar.


It connects directly to all lithium NG batteries in the system for centralized monitoring. It also receives power and state of charge data directly from the batteries, eliminating the need for a separate SmartShunt. All data can be read out via VictronConnect using the built-in Bluetooth.

The lithium-NG batteries can be configured in series, parallel or a combination of both and support 12V, 24V and 48V systems. A maximum of 50 batteries can be used in 12 V or 24 V banks and 25 batteries in 48 V banks, allowing storage of up to 192 kWh (12 V), 384 kWh (24 V) and 128 kWh (48 V). Multiple Lynx Smart BMS units can be connected in parallel to expand capacity and provide redundancy.

Load Disconnect output
The load output is normally high and becomes free floating when the cell is energized (standard 2.8 V/cell,
adjustable at the battery between 2.6 V and 2.8 V per cell). Maximum current: 1 A. The load output is not
short-circuit protected.
The "Load" output can be used to control the following functions:
- A high current relay or contactor
- The remote on/off input of BatteryProtect, inverter or DC-DC converter or other loads.
(A non-inverting or inverting cable for on/off switching may be necessary. Please refer to the detailed manual on our website
.)


"Charge disconnect"output
The "Charger" output is normally HIGH and becomes "free floating" when a cell overvoltage or overtemperature is imminent. Maximum current: 10 mA.
The "Charger" output is not suitable for operating an inductive load such as a relay coil.
The "Charger" output can be used to control the following devices:
- Remote on/off switch of a charger
- Cyrix-Li charging relay.
- Cyrix-Li-ct battery coupler
- Solid Switch (for controlling larger loads up to 70V / 4 A


Pre-alarm output
The pre-alarm output is normally free-floating and goes high if there is a risk of undervoltage in the cell (standard 3.1
V/cell, adjustable on the battery between 2.85 V and 3.15 V per cell). Maximum current: 1 A (not short-circuit proof).
The minimum delay between pre-alarm and load disconnection is 30 seconds.


"System on/off" input
The "System on/off" input controls both outputs. If it is off, both outputs are switched to "free floating". The loads
and chargers are therefore switched off.
The "System on/off" input has two connections: Remote L and Remote H.
A remote on/off switch or a relay contact can be connected between L and H.
Alternatively, connection H can be connected to a battery positive terminal or L to a battery negative terminal.


ntegratedbattery monitor
The integrated battery monitor can be read out via Victron Connect, and all battery data such as cell voltage and history can also be read out.
A low SOC alarm can be set.


Protects 12V, 24V and 48V systems
Operating range voltage 8 to 70V DC.


LED indicators
- load ON (blue): Load output high (cell voltage > 2.8 V, adjustable at the battery).
- Temp or OVP (red): Charger output "free floating" (due to cell overtemperature (>50°C), cell
undertemperature (< 5 C) or cell overvoltage).

VictronConnect

With VictronConnect you can query live status information and configure all Victron products that either have a built-in Bluetooth function or are connected to a VE.Direct Bluetooth Smart Dongle.

Further information in the VictronConnect manual