Keep your trailer?s battery fully charged while on the move eliminating the need for unnecessary idling and reducing the dependence on shore power charging.?Designed with REDARCs tried and tested charging technology, the BCDC Trailer S features a DC-DC charger, an MPPT solar regulator and a smart battery isolator all packed into one compact, lightweight unit. The BCDC Trailer S has an input current limit specifically designed to allow you to connect directly through your trailer?s 7-way plug and existing vehicle wiring for easy installation.?Suitable for applications where the input current required to charge the trailer battery is drawn through the vehicle's towing harnesses and connectors. The ideal battery charger for enclosed trailers - such as travel trailers, horse trailers, mobile service vehicles & emergency vehicles.?