Charge equalisers are designed to manage a high current 12 volt supply in a 24 volt battery system. While charge equalisers also have a place in home solar systems they are commonly used in recreational vehicles, boats, large trucks or motor homes.
Unlike common voltage reducers (which in effect are current limiting devices), charge equalisers draw power directly from the 24 volt battery - hence allowing much larger peak currents. In fact, peak load currents available are limited only by the battery.
The equaliser 'taps' into the 12V from the lower battery of your 24V system without flattening the lower battery or overcharging the upper battery (keeping the batteries equalised).
This is particularly useful when space or budget restrictions prohibit the installation of an additional 12 volt battery*.
The output voltage of a charge equaliser is regulated to half the input voltage. Therefore, the output voltage of the charge equaliser fully depends on the actual voltage of the 24V battery bank, which changes significantly with the vehicle's motor running.
- With the motor running, the vehicle's battery may read 28V, thus the equaliser's output would be 14V ± 0.25V - safe enough to operate 12V equipment and sufficient to even charge a separate 12 volt battery*.
- With the motor not running, the vehicle's battery typically measures 24V, and the equaliser's output would be 12V ± 0.25V. Enough to operate 12V equipment but not enough to charge an additional battery*.
*An additional 12V battery must be isolated to prevent discharge back into the 24V system.