The TBCM-40A Trailer Battery Charging Module senses the alternator charge voltage of the towing vehicle and sends charge current to the trailer battery. When the vehicle is not running, the TBCM-40A disconnects the trailer battery from the vehicle’s charge wire to prevent having two dead batteries. The TBCM-40A works with existing 12 volt trailer wiring, including on-board 110 volts AC chargers, and handles most towing vehicle alternators.
The TBCM-40A is mounted in the trailer battery box or engine compartment and only requires three wires for connection. The TBCM-40A does not have a .6 volt drop to sulfate your battery like RV type isolators.
Dimensions: W: 1.20” x H: 1.2" x D: 3.20"