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Victron smallBMS

Original price was: $83.16.Current price is: $75.60. (inc. GST)

Victron smallBMS is a compact and lightweight battery management system designed for small to medium-sized lithium-ion battery systems. It is compatible with Victron’s Smart Battery Sense technology and can be used with a range of battery types, including LiFePO4, NMC, and NMC-HD. The smallBMS is designed to protect the battery from overcharging, over-discharging, and short-circuiting, thereby increasing the lifespan of the battery and ensuring safe operation. It is also capable of monitoring battery health and providing real-time information on the battery’s state of charge, voltage, and temperature. With its compact size and user-friendly interface, the Victron smallBMS is a popular choice for DIY enthusiasts and small-scale energy projects.

SKU: BMS400100000 Categories: ,

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 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 input of a Battery Protect, inverter or DC-DC converter or other loads.

(a non-inverting or inverting on/off cable may be required, please consult the detailed manual on our website)
Pre-alarm output-

The pre-alarm output is normally free floating and becomes high in case of 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 over voltage 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 (>50°C), cell under temperature (<5 °C) or cell over voltage).

Additional information

Normal operating Input voltage range (Vbat)

8 – 70V DC

Current draw, normal operation

2.7 mA (excluding Load output and Charger output current)

Current draw, low cell voltage


Current draw, remote off

1,5 mA

Load output

Normally high (Vbat – 0.1V)

Source current limit: 1A (not short circuit protected)

Sink current: 0A (output free floating)

Charger output

Normally high (Vbat –o.6V)

Source current limit: 10mA (short circuit protected)

Sink current: 0A (output free floating)

System on/off: Remote L and Remote H

Use modes of the system on-off:

a.ON when the L and H terminal are interconnected (switch or relaycontact)

b. ON when the L terminal is pulled to battery minus (V<3.5V)

c. ONwhentheHterminalishigh(2.9V<VH<Vbat)

d. OFF in all otherconditions

Operating temperature

-20 to+50°C 0 -120°F


Max. 95% (non-condensing)

Protection grade


Material and colour

ABS, matt black



Dimensions (h x w x d)

106 x 42 x 23mm

Standards: Safety Emission Immunity Automotive


EN 61000-6-3, EN 55014-1

EN 61000-6-2, EN 61000-6-1, EN 55014-2

Regulation UN/ECE-R10 Rev.4


Datasheet-smallBMS-with-pre-alarm-ENVictron small BMS spec sheet-