Victron Energy Battery Balancer, For 24V Systems, 0.7A Balancing Current

Overview

The Victron Energy BBA000100100 is a Battery Balancer for two 12V batteries connected in series, or for several parallel strings of series-connected 12V batteries in a larger bank. It helps keep the two battery halves at the same state of charge, which matters on boats with 24V DC systems where one battery can otherwise end up working harder than the other during charging and use.

When the charge voltage of a 24V battery system rises above 27.3V, the unit turns on and compares the voltage across the two batteries. Balancing starts from a 50 mV midpoint deviation, with up to 0.7A of balancing current when the deviation is above 100 mV. For 48V banks, three Battery Balancers can be used across the series-connected batteries.

The housing is rated IP22, so it belongs in a dry, protected electrical space rather than an exposed cockpit, wet bilge, or washdown area. Its compact 100 x 113 x 47 mm size makes it practical for mounting near a house battery bank, equipment locker, or DC distribution area where the wiring can stay short and service access remains clear.

Key features

• Balances two series-connected 12V batteries in a 24V bank, or parallel strings of series-connected batteries.
• Turns on during charging when system voltage rises above 27.3V and begins balancing from a 50 mV midpoint deviation.
• Draws up to 0.7A from the higher-voltage battery side to help the bank return toward an even state of charge.
• Supports 48V battery banks when three Battery Balancers are installed across the series-connected batteries.
• LED status indicators show power, upper or lower battery leg balancing activity, and alarm condition.
• Normally open 60V / 1A alarm relay can be tied into a remote alert or monitoring circuit.
• Screw terminals accept up to 6 mm² / AWG10 conductors, with separate terminals available for alarm reset.
• Operating temperature range of -30°C to +50°C suits protected marine electrical spaces that see seasonal temperature swings.
• IP22 enclosure is suitable for dry mounting locations where the unit is protected from spray and direct water exposure.

Installation and setup

Mount the balancer on a well-ventilated vertical surface close to the batteries, but not directly above them where corrosive battery gases may rise. On a boat, a protected battery compartment wall or nearby electrical panel backing board is usually a better location than the top of the battery box.

For the main negative, positive, and midpoint connections, use at least 0.75 mm² wiring and keep the runs neat, supported, and protected from chafe. In installations that need UL compliance, each of these wires should be fused near the batteries with a 10A fuse suitable for DC current.

Electrical and system integration

The Battery Balancer is most useful on 24V and 48V battery banks built from 12V batteries in series. It is not a solar charge controller and does not replace correct charging settings, proper battery matching, or routine battery maintenance. Its job is to manage midpoint imbalance while the bank is charging.

The alarm relay closes when the midpoint deviation reaches the alarm level, giving installers a clean way to add a remote warning light, buzzer, or monitoring input. The relay resets once the deviation drops back within range, and a separate push-button reset can be wired to the reset terminals when a manual reset point is useful at the DC panel.

Use cases on board

This unit is a good match for boats running a 24V house bank, inverter bank, or other series-connected battery setup where long battery life depends on keeping the two sides of the bank balanced. It is especially relevant for vessels that spend time on shore power, solar charging, alternator charging, or generator charging where repeated charge cycles can expose small differences between batteries.

For cruising boats, workboats, and fishing boats with higher-capacity DC systems, the balancer gives a simple way to reduce uneven charging stress without adding a complex control interface. It works quietly in the background once installed and gives clear LED feedback when balancing or alarm conditions occur.

Maintenance and care

Keep the unit dry, clean, and accessible for inspection. During routine battery checks, confirm that the terminals remain tight, wiring is supported, and the enclosure has not been exposed to water, salt residue, or corrosive fumes.

If an alarm appears on a new battery bank, the batteries may have started with different states of charge and may need to be charged individually before the system is put back into normal service. On an older bank, repeated alarms can point to undercharging, cell problems, or batteries that no longer age evenly.