The Amazing Quality Convenient Dual Battery Bank ChargingXantrex digital echocharge (part#82-0123-01) is designed to charge auxiliary or starting batteries from an inverter/charger or other charging source with limited voltage drop. The Xantrex echocharge detects when the house battery bank is being charged and directs a portion of the charge current to auxiliary or starting batteries. The maximum charger current offered by echocharge is limited to 15 amps.Product Features15 A maximum charge current Automatically adjusts for 12 or 24 volt battery banks (both battery banks must be the same DC voltage and battery type) Automatically switches on/off without affecting the in-house battery bank or over-charging Utilizes excess current from the primary charging source Built-in thermal and over-current circuits Reverse polarity protection Easy three wire installation