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Victron miniBMS /smallBMS
Pre-alarm output, load/charge disconnect, 8-70V DC, 106x42x23mm
Victron miniBMS /smallBMS NGDESCRIPTION
Victron smallBMS NG: Advanced Battery Management for Victron Smart Lithium Systems
Precision Protection for 12V, 24V, and 48V LiFePO4 Battery Banks
The Victron smallBMS NG (BMS400100000) is a compact, next-generation battery management system engineered to safeguard Victron Smart LiFePO4 batteries in off-grid, marine, and mobile applications. Replacing the earlier miniBMS, this unit delivers reliable cell-level monitoring and control without the complexity or cost of a full VE.Bus BMS. It is purpose-built for systems where a VE.Bus interface is not required, making it an ideal match for standalone inverters, DC-DC converters, and solar charge controllers.
Designed for seamless integration with Victron’s M8 circular connector Smart Lithium batteries, the smallBMS NG actively prevents deep discharge, overcharge, and temperature extremes. Its three independent outputs—Load Disconnect, Charge Disconnect, and Pre-Alarm—provide layered protection that extends battery service life and enhances system safety. Whether you are building a 12V caravan solar setup, a 24V marine power system, or a 48V off-grid energy storage solution, this BMS ensures your lithium investment remains protected under all operating conditions.
Three-Stage Protection Architecture
The smallBMS NG continuously monitors individual cell voltages and battery temperature via the Victron battery’s internal BMS communication. When parameters approach critical thresholds, it initiates a sequenced response:
- Load Disconnect Output: Normally high (Vbat – 0.1V), this output transitions to free floating when any cell drops below the under-voltage threshold (default 2.8V/cell, adjustable 2.6–2.8V). With a 1A source current limit, it can directly drive a high-current relay, contactor, or the remote on/off input of a Victron BatteryProtect, inverter, or DC-DC converter. This prevents irreversible cell damage from over-discharge.
- Pre-Alarm Output: Provides an early warning signal before load disconnect occurs. Normally free floating, it activates (Vbat – 0.1V, 1A max) when cell voltage falls to the pre-alarm threshold (default 3.1V/cell, adjustable 2.85–3.15V). A minimum 30-second delay before load disconnect gives systems time to shed non-critical loads or start a generator, avoiding unexpected shutdowns.
- Charge Disconnect Output: Normally high (Vbat – 0.6V), this output goes free floating to signal an imminent cell over-voltage or over/under-temperature condition. With a 10mA source current limit and short-circuit protection, it is designed to control the remote on/off of chargers, Cyrix-Li-Charge relays, or Cyrix-Li-ct Battery Combiners. This ensures charging stops before cells exceed safe voltage or temperature limits.
Flexible System On/Off Control
The Remote L and H terminals allow straightforward system-wide on/off switching. Three control modes are supported: bridging L and H, pulling L to battery negative (<3.5V), or applying a high signal to H (2.9V to Vbat). This flexibility simplifies integration with external switches, BMS panels, or automated controllers, enabling a single point of control for both loads and chargers.
Built for Harsh Environments
Housed in a matt black ABS enclosure rated IP20, the smallBMS NG measures just 106 x 42 x 23 mm and weighs 0.1 kg. It operates across a wide temperature range of -20 to +50°C and tolerates up to 95% non-condensing humidity. The compact footprint allows installation in tight electrical compartments typical of caravans, boats, and equipment cabinets. Status LEDs provide immediate visual feedback: a blue Load ON indicator confirms active load output, while a red Temp or OVP LED warns of charge disconnect due to temperature or over-voltage events.
Why Choose the Victron smallBMS NG?
- Direct compatibility with Victron Smart LiFePO4 batteries featuring M8 circular connectors—no additional interfaces required.
- Wide operating voltage range of 8–70 VDC supports 12V, 24V, and 48V nominal systems from a single model.
- Ultra-low power consumption: typically 2.2 mA when remote on, minimising parasitic drain on the battery bank.
- Pre-alarm functionality reduces the risk of sudden system shutdowns by providing advance warning of low cell voltage.
- Automotive-grade compliance to UN/ECE-R10 Rev.4, plus safety and EMC standards (EN 60950, EN 61000-6-3, EN 55014-1, EN 61000-6-2, EN 61000-6-1, EN 55014-2), ensuring reliable operation in vehicle and marine environments.
Applications
The smallBMS NG is the preferred battery management solution for Victron lithium systems where a VE.Bus MultiPlus or Quattro inverter/charger is not used. Typical installations include:
- Caravans and camper trailers with standalone inverters and MPPT solar controllers.
- Marine electrical systems using alternator charging via Cyrix-Li-ct relays.
- Remote off-grid cabins and tiny homes with DC-only or non-VE.Bus AC systems.
- Portable power packs and mobile workstation setups.
By offloading critical protection functions to a dedicated BMS, you reduce the risk of cell damage, improve system reliability, and simplify wiring compared to generic or multi-brand solutions. The smallBMS NG is not suitable for use with VE.Bus inverter/chargers; for those applications, consider the VE.Bus BMS.
Protect Your Lithium Investment
Equip your Victron Smart Lithium battery bank with the smallBMS NG and gain confidence that your cells are monitored and protected around the clock. Order the Victron smallBMS NG today and build a safer, longer-lasting energy system for your next adventure or off-grid project.
SKU: VIC-BMS400100000
SPECIFICATIONS
Specifications
| Product | smallBMS with pre-alarm BMS400100000 |
| Operating voltage (Vbat) | 8 – 70 VDC |
| Power supply cable and fuse (not supplied) | Recommended fuse size 0.3 A - 2.5 A, dependent on devices connected to Load disconnect and pre-alarm output |
| Current consumption, remote on | 2.2 mA (excluding Load and Charge disconnect output current) |
| Current consumption, low cell voltage | 1.2 mA |
| Current consumption, remote off | 1.2 mA |
| Load disconnect output | Normally high (Vbat – 0.1 V) Source current limit: 1A (not short circuit protected) Sink current: 0A (output free floating) |
| Charge disconnect output | Normally high (Vbat –0.6 V) Source current limit: 10mA (short circuit protected) Sink current: 0A (output free floating) |
| Pre-alarm output | Normally free floating In case of alarm: output voltage Vbat -0.1 V Maximum output current: 1A (not short circuit protected) |
| Remote on/off | Remote L and Remote H Use modes: 1. ON when the L and H terminal are interconnected 2. ON when the L terminal is pulled to battery minus (V <3.5 V) 3. ON when the H terminal is high (2.9 V <VH <Vbat) 4. OFF in all other conditions |
| GENERAL | |
| Operating temperature range | -20 to +50 °C (0 – 120 °F) |
| Humidity | Max. 95 % (non-condensing) |
| Protection grade | IP20 |
| ENCLOSURE | |
| Material and colour | ABS, matt black |
| Weight | 0.1 kg |
| Dimensions (h x w x d) | 106 x 42 x 23 mm |
| STANDARDS | |
| Safety | EN 60950 |
| Emission | EN 61000-6-3, EN 55014-1 |
| Immunity | EN 61000-6-2, EN 61000-6-1, EN 55014-2 |
| Automotive | Regulation UN/ECE-R10 Rev.4 |
| SKU: | VIC-BMS400100000 |
| Barcode: | 8719076043485 |
| Model #: | BMS400100000 |
| MPN: | BMS400100000 |
WARRANTY
Victron Energy Limited Warranty Policy
Victron Energy warrants its products to be free from defects in workmanship and materials for a period of 5 years from the date of purchase by the end user, with a maximum of 66 months from the Victron Energy invoice date. Exceptions on this are: lead acid batteries; 2 years from date of purchase by the end user, with a maximum of 30 months from the Victron Energy invoice date, Lithium-ion batteries; 3 years from date of purchase by the end user. In addition to this proof of correct battery usage is required when making a battery warranty claim.
During this period, Victron Energy will, at its option, repair or replace the defective product free of charge. The warranty does not include performing or reimbursing de‐installation, transportation and re‐installation. This warranty will be considered void if the unit has suffered any physical damage or alteration, either internally or externally, and does not cover damages arising from improper use like: • Reverse of battery polarity. • Inadequate connection. • Mechanical shock or deformation. • Contact with liquid or oxidation by condensation. • Use in inappropriate environment (dust, corrosive vapor, humidity, high temperature, biological infestation...). • Breakage or damage due to lightning. • Connection terminals and screws destroyed or other damages, like overheat, due to insufficient tightening. • For any electronical breakage except due to lightning (reverse polarity, over‐voltage due to external cause), the state ofthe internal control diode and of the inputs/output X and Y capacitors determine the warranty.
This warranty will not apply where the product has been misused, neglected, improperly installed, or repaired by anyone else than Victron Energy or one of its authorized Qualified Service Partners. In order to qualify for the warranty, the product must not be disassembled or modified.
Repair or replacement are our sole remedies and Victron Energy shall not be liable for damages, whether direct, incidental,special, or consequential, even caused by negligence or fault.
Victron Energy owns all parts removed from repaired products. Victron Energy uses new or reconditioned parts made by various manufacturers in performing warranty repairs and building replacement products. If Victron Energy repairs or replaces a part of a product, its warranty term is not extended. In case of replacement the new component has a warranty of 6 months, without effect on the initial warranty period. All remedies and the measure for damages are limited to the above. Victron Energy shall in no event be liable for consequential, incidental, contingent orspecial damages, even if having been advised of the probability of such damages. Any and all other warranties expressed or implied arising by law, course of dealing, course of performance, usage of trade or otherwise, including but not limited to implied warranties of merchantability and fitness for a particular purpose, are limited in duration to a period of two (2) years from the date of purchase.
Life Support Policy As a general policy, Victron Energy, does not recommend the use of any of its products in life support applications where failure or malfunction of the Victron Energy's product can be reasonably expected to cause failure of the life support device or to significantly affect its safety or effectiveness. Victron Energy does not recommend the use of any of its products in direct patient care. Victron Energy will not knowingly sell its products for use in such applications unless it receives in writing assurances satisfactory to Victron Energy that the risks of injury or damage have been minimized, the customer assumes all such risks, and the Liability of Victron Energy is adequately protected under the circumstances.
As a product requires service, it must be brought back to the place of purchase. In case no contact can be taken with the merchant, or if he is either unable or not allowed to provide service, direct contact should be taken with Victron Energy.
Warranty on Repairs The warranty period on products or on printed circuits boards repaired by Victron Energy as well as on printed circuit boards for replacement is 6 months from delivery by Victron Energy.
Transport It is the responsibility of the sender to sufficiently package these products. The transport must be organized in a way to avoid any damage, especially when a single unit or heavy unit is sent.
Severability If a part of the terms and conditions set out above is held invalid, void or unenforceable due to any particular national or international legislation, it shall not affect other parts of the terms and conditions remaining.
For Australia only Our goods come with guarantees that cannot be excluded under the Australian Consumer Law. You are entitled to a replacement or refund for a major failure and compensation for any other reasonably foreseeable loss or damage. You are also entitled to have the goods repaired or replaced if the goods fail to be of acceptable quality and the failure does not amount to a major failure.
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