Victron smallBMS NG Battery Management System | BMS400100300

The Victron Energy smallBMS NG is a compact battery management system built for Victron LiFePO4 batteries in smaller off-grid and marine setups. It guards against over-charge, over-discharge and over-temperature conditions, suited to systems where a full-featured BMS would be more than is needed.

Key features

• Cell protection, guards against over-voltage, under-voltage and over-temperature on compatible Victron LiFePO4 batteries.
• Weight, 66 g, for space-constrained installs in boats, campervans and small off-grid cabins.
• Load disconnect output, cuts non-essential loads once the battery reaches a low state of charge.
• Charge disconnect output, signals chargers to stop when the battery is full or a cell fault is detected.
• NG variant, updated internal architecture for compatibility with the current Victron LiFePO4 battery range.
• Wiring, clearly defined load disconnect and charge disconnect terminals.

Product overview

The smallBMS NG monitors individual cell voltages and battery temperature within compatible Victron LiFePO4 batteries. When a cell hits its upper or lower voltage limit, or temperature moves outside the safe range, the BMS activates its disconnect outputs. It is a passive protection approach: the unit does not actively balance cells, relying instead on the battery's internal balancing and the charger's absorption settings.

The charge disconnect output is typically wired to the remote on/off input of a Victron charger or MPPT solar charge controller. The load disconnect output goes to a relay or load switch, shedding non-critical loads before the battery reaches a damaging depth of discharge. No high current is routed through the BMS itself, keeping the unit small and the wiring tidy.

NG marks this as the current production version, updated for compatibility with Victron's present LiFePO4 battery range, and replaces the earlier smallBMS variant for new installations.

Applications

• Small off-grid cabins and garden buildings running a single Victron LiFePO4 battery.
• Marine installations including sailing yachts, motorboats and narrowboats with compact lithium banks.
• Campervan and motorhome leisure battery systems using Victron LiFePO4 batteries.
• Portable power systems and small solar storage setups.
• Replacement or upgrade from the original smallBMS in existing Victron lithium installations.

What's in the box

• 1 x Victron Energy smallBMS NG unit

Installation notes

Use only with compatible Victron LiFePO4 batteries. Not suitable for lead-acid, AGM, gel or third-party lithium batteries. Wiring should be carried out by a qualified electrician or experienced marine or off-grid installer familiar with lithium systems. Incorrect wiring of either disconnect output can damage the battery or cause system failure. Check compatibility with your specific Victron LiFePO4 battery model before fitting.