Victron SmallBMS for Smart LiFePO4 Batteries with M8 connectors is a compact protection and control module designed to replace the VE.Bus BMS in a range of installations. It supports Victron Smart LiFePo4 batteries with M8 circular connectors and emphasizes straightforward installation and essential protection.
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3 protective outputs: Load Disconnect, Pre-alarm, and Charger output, mirroring the essential functions of a VE.Bus BMS.
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Load Disconnect: Normally high and becomes free-floating if a cell drops below the set threshold (default 2.8 V per cell; adjustable 2.6–2.8 V per cell). Maximum current: 1 A. Not short-circuit protected. Ideal for driving a high-current relay or contactor, or for remote on/off control of loads such as inverters or DC‑DC converters.
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Pre-alarm: Normally free-floating and goes high when imminent cell under-voltage is detected (default 3.1 V per cell; adjustable 2.85–3.15 V per cell). Maximum current: 1 A (not short‑circuit protected). Minimum 30 seconds between pre‑alarm and load disconnect to allow safe transitions.
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Charger Disconnect: Normally high and becomes free-floating on imminent cell overvoltage or over‑temperature. Maximum current: 10 mA. Not suitable for inductive loads. Use it to control the remote on/off of a charger, a Cyrix-Li-Charge relay, or a Battery Combiner System on/off input.
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System on/off and remote control: The system on/off input controls both outputs. The two terminals Remote L and Remote H accept a remote switch or relay between them; alternatively, H can be switched to battery plus and/or L to battery minus. When the system is off, both outputs become free-floating, turning off loads and chargers.
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Electrical compatibility and indicators: Protects 12 V, 24 V and 48 V systems with an operating range of 8 to 70 V DC. LED indicators: Load ON (blue) shows when the Load output is high (cell voltage > 2.8 V, adjustable on the battery). Temp or OVP (red) indicates charger output has freed due to cell over temperature (>50°C), cell under temperature (<5°C), or cell over voltage.
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Designed for Victron Smart LiFePo4 batteries with M8 connectors: The SmallBMS provides robust protection, flexible control, and straightforward installation at a fraction of the cost of other bus systems. It enables reliable load isolation, proactive cell‑voltage monitoring, and controlled charging actions across 12 V, 24 V and 48 V configurations.
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Compatibility note: Replacement for VE.Bus BMS in several applications, but not suitable for VE.Bus MultiPlus and Quattro inverter/chargers due to the absence of a VE.Bus interface.
The Victron SmallBMS provides essential protection and precise, flexible control for Smart LiFePo4 packs. It enables reliable load isolation, proactive cell-voltage monitoring, and controlled charging actions across 12 V, 24 V, and 48 V system configurations.
