Redarc charge equaliser operates in a two-battery 24VDC -ve Earth system. The output voltage of the charge equaliser is regulated to half the input voltage. 12V power is available from the lower battery in a 24V system via the centre tap. It ensures tha the voltage in the lower 12V battery is equalised to the voltage of the upper 12V battery in the 24V bank Alternatively it can be used to maintain charge in a separate 12V auxiliary battery The CE 13.8 models are used to charge a 12V battery from a 24V electrical system