The Victron BatteryProtect 48V-100A is an automatic battery isolator switch that protects 48V battery banks from over-discharge. It disconnects the load before voltage drops to a critically low level, guarding cells against damage and helping extend battery service life. It suits off-grid solar systems, marine installations and other 48V DC setups where load shedding is needed.

Key features of this battery isolator switch

• Current rating, 100A continuous on a 48V system.
• Automatic disconnect, triggers on low battery voltage with a configurable reconnect threshold.
• Low self-consumption, minimal parasitic drain on the battery bank when idle.
• Remote on/off input, integrates with battery management systems, inverters or a manual switch.
• Alarm output, gives a pre-disconnect warning so loads can shut down before isolation.
• Chemistry compatibility, works with lithium (LiFePO4) and lead-acid batteries, with thresholds set via a rotary switch.
• Weight, 0.8 kg, suitable for panel or DIN rail mounting.

How it works

The unit monitors battery voltage continuously. Once voltage falls to the programmed disconnect point, it opens the load circuit and holds it open until the battery recovers to the reconnect voltage, avoiding the sustained low-voltage conditions that cause capacity loss in lead-acid and lithium cells. Pre-set voltage profiles are selected via the rotary switch, without programming tools.

The remote input accepts a signal from a Victron BMV battery monitor, a BMS, or a simple switch, so the unit can be overridden or controlled within a larger system. The alarm output can drive an LED indicator or feed a monitoring system, giving warning ahead of full disconnect.

This is a load-side device only. It should be wired between the battery and the loads, not between the battery and the charger.

Applications

• Off-grid solar systems with 48V battery banks needing automatic disconnect on low voltage.
• Marine and narrowboat DC systems protecting auxiliary load circuits.
• Motorhome and vehicle conversions running 48V DC distribution.
• Telecom and remote monitoring installations with 48V battery backup.

Installation notes

Fit on the load side of the battery bank, never in the charge circuit. Wiring should be sized for 100A continuous current and protected with a suitably rated fuse. Installation should be carried out by a qualified electrician familiar with DC battery systems, observing relevant wiring regulations.

What's in the box

• 1 x Victron BatteryProtect 48V-100A (BPR048100400)