Twin-engine applications provide unique challenges, and unique benefits when charging a large, single battery bank. The CF-12/24-II was designed to address the twin engine conundrum by allowing port and starboard charging systems to work together and offer the output from both alternators to be combined to optimize charging output. When it detects both regulators are active (both engines are running), the CF-12/24-II directs field current from the dominant voltage regulator to both alternators, so the combined output can be utilized to charge a large battery bank more quickly and efficiently. The CF-12/24-II provides 5-LED indicators to identify system functions, as well as larger-gauge fused regulator power wires to ensure proper current flow. For use with Max Charge 12-volt, Model 12032983 (MC-614-H) or 24-volt, Model 1234178 (MC-624-H) regulators only.