Electronic unit designed to preserve the battery charge.The unit is autoranging to automatically sense the voltage of the system (12 or 24V).It preserves the main battery (starting) power by isolating the auxiliary battery when the system voltage drops below a critical level and it automatically reconnects the battery banks when voltage rises to the correct level. Compatible with electronically controlled alternators, it eliminates false battery warnings created by diode isolators and protects devices from overcurrent.