Victron battery balancer
The balancer monitors and compensates for battery charging differences.
The life of a battery bank can be significantly shortened by the charging imbalance of the individual batteries. This is the situation when you have 12 V batteries connected in series or series-parallel (not just in parallel!). In such a system, one 12 V battery with a slightly higher internal resistance can cause undercharging of parallel connected batteries and overcharging of series connected batteries. New battery cells or entire batteries connected in series have almost identical initial properties. Their small differences are equalized during the absorption or equalization phase of charging. However, large differences can lead to excessive gassing caused by overcharging of more charged batteries and undesirable sulfation of less charged batteries caused by undercharging.
The solution is balanced charging using a battery balancer. This balancer equalizes the charge state of two 12 V batteries connected in series or several parallel strings of batteries connected in series. As soon as the charging voltage in a 24 V system increases to more than 27.3 V, the battery balancer is activated and compares the voltages of the two batteries connected in series. The balancer can redirect a current of up to 0.7 A from one battery (or batteries connected in parallel) with a higher voltage to the other battery. The result of the different charging currents is that the final state of charge of all batteries is identical.
Battery balancers can also be connected in parallel for more complex systems. For a 48 V system, a total of three balancers are used (see diagrams).
Explanation of LED indicators:
Green LED: device is active and measured voltage is higher than 27.3 V
Upper orange LED: voltage deviation is greater than 0.1 V
Lower orange LED: voltage deviation is greater than 0.1 V
Red LED: alarm triggered if the difference between the monitored batteries is greater than 0.2 V. The alarm persists until the difference is less than 0.14 V or the system voltage drops below 26.6 V.
The meaning of the alarm relay
In the standard state it is open (inactive). It is closed (activated) when the red LED lights up, i.e. when the voltage difference between the batteries is higher than 0.2 V. As soon as the red LED goes out, the relay opens (deactivates) again (the drop in the voltage difference between the batteries is less than 0.14 V).
Alarm reset
The alarm can be turned off by connecting the outputs marked RESET together. This can be done using a switch.
Installation
- The battery balancer(s) must be installed on a well-ventilated vertical surface near the batteries (but not directly above them due to the possible influence of battery gases!)
- If required, install alarm contact wiring and reset wiring.
- Use a minimum cable size of 0.75 mm2 to connect the negative, positive and neutral poles (in that order!)
The balancer is ready for operation. If the voltage on any of the monitored batteries (strings) rises above 27.3 V (during charging), the green LED will light up, which means that the balancer is activated. If in this situation the deviation of the batteries (strings) is greater than 50 mV, active balancing begins, i.e. compensation of the difference of the batteries (strings). If the deviation reaches 100 mV, it activates withe one of the orange LEDs. A deviation greater than 200 mV will trigger the alarm relay. In series-parallel battery connections, the central interconnecting wiring between the parallel strings must be sized to handle the current if part of the battery is disconnected.
BASIC SPECIFICATIONS
Input voltage range: up to 18 V per battery, 36 V total
Voltage level for balancer activation: 27.3 V ±1%
Balancer deactivation voltage level: 26.6 V ±1%
Power consumption in deactivated state: 0.7 mA
Power consumption in activated state: 50 mV
Maximum balance current: 0.7 A at a deviation of 100 mV and more
Voltage deviation for alarm triggering: 200 mV
Voltage deviation for alarm shutdown: 140 mV
Alarm relay: 60 V/1 A, normally open
Method of turning off the alarm relay: connecting two outputs marked as RESET
Overheating protection: yes
Operating temperature range: -30 to + 50 °C
Maximum humidity: up to 95% (non-condensing)
Housing color: blue (RAL 5012)
Connection contacts: 6 mm 2 /AWG10, screw fastening
Protection class: IP22
Weight: 0.4 kg
Dimensions: 113 x 100 x 47 mm
