Probably this question is better suited for the motor home channel however I will give it go here . I am trying to understand the purpose of a latching relay and then another solenoid (relay) to contr...
A latching relay draws no power after function is accomplished. My guess for second large relay for charging goes through a circuit board that requires the charging system battery to be nearly charged before energizing that relay. Yes, sometimes small relays are used for control. Doubt that a large relay would be used as control.