Victron Battery Balancer 24V Systems

The Victron Battery Balancer (BBA000100100) is a state-of-charge equaliser designed to prevent capacity loss and battery damage caused by cell voltage imbalance in 24V and 48V lead-acid battery banks built from series-connected 12V batteries. By automatically drawing current from whichever battery has the highest voltage during the absorption and equalisation phase of charging, it ensures all batteries in a series string converge to the same state of charge — protecting the battery bank from the overcharging and sulfation damage that imbalance progressively causes.

The Battery Balancer activates automatically when the total charging voltage of a 24V system rises above 27.3V — the threshold at which the batteries are entering the absorption charge phase and any state-of-charge imbalance will be amplified. Once active, the balancer compares the voltages across the two series-connected 12V batteries (or parallel groups) and draws up to 0.7A from whichever battery has the higher voltage. This redirects effective charging current toward the lower-voltage battery until both converge to the same voltage and state of charge. The balancer then turns off when the system voltage drops back below 26.6V.

For 48V systems built from 12V batteries in series, three Battery Balancers are required — one across each adjacent pair in the four-battery string. Multiple balancers can also be connected in parallel across a single battery pair to increase balancing current in larger parallel battery strings. A normally-open alarm relay closes and the red LED illuminates when the voltage deviation between the two battery legs exceeds 0.2V — triggering an external alarm, relay, or buzzer. The relay can be reset via a push button connected to the two reset terminals.

Three LED indicators provide clear at-a-glance status: green when the system is active (voltage above 27.3V), orange for each leg when that leg is being actively balanced (deviation above 0.1V), and red when the deviation alarm threshold is exceeded (deviation above 0.2V).

Features

Equalises State of Charge in Series-Connected 12V Battery Banks

The Battery Balancer draws balancing current from the higher-voltage battery in a series string, ensuring both batteries reach the same state of charge during every absorption charge cycle — preventing the progressive imbalance that leads to overcharging, excessive gassing, and sulfation damage in 24V and 48V lead-acid battery banks.

Automatic Activation and Deactivation

The balancer activates automatically when the 24V system voltage rises above 27.3V (absorption phase) and deactivates when it drops below 26.6V — requiring no manual operation or configuration, and adding no parasitic load on the battery when the system is not charging.

Alarm Relay and Red LED Warning

A normally-open alarm relay closes and the red LED illuminates when the voltage deviation between the two battery legs exceeds 0.2V — alerting users to a significant imbalance condition via an external alarm device, buzzer, or monitoring system. The relay resets automatically when the deviation drops below 0.14V, or can be manually reset via a push button connected to the two reset terminals.

Three LED Status Indicators

A green LED confirms the balancer is active and the system voltage is above the 27.3V activation threshold. Two orange LEDs indicate which battery leg is being actively balanced (deviation above 0.1V). A red LED signals the alarm condition (deviation above 0.2V), remaining on until the deviation reduces below 0.14V or system voltage drops below 26.6V.

Suitable for 24V and 48V Systems

One Battery Balancer is required for a 24V system (two 12V batteries in series). For a 48V system built from four 12V batteries in series, three Battery Balancers are required — one across each adjacent pair in the string. Multiple balancers can be connected in parallel at each position to increase balancing current for larger parallel battery strings.

Works with All Lead-Acid Battery Types

Compatible with all 12V lead-acid battery types including flooded, GEL, and AGM — making it suitable for all legacy and current Victron and third-party 12V lead-acid batteries used in series to create 24V or 48V battery banks.

Pairs with BMV-702 Midpoint Monitoring

The Victron BMV-702 battery monitor includes a midpoint monitoring function that measures the voltage deviation between the two halves of a series-connected battery bank, displaying it as a percentage or voltage. Used alongside the Battery Balancer, it provides additional insight into long-term battery bank balance and can trigger independent alarms when preset deviation thresholds are exceeded.

Specifications

Manuals and Dimension Drawing

Product Manual

Dimension Drawing