Purkeys’ SteadyCharge Accessory Battery Charger is designed to monitor and maintain an optimal charge level in accessory batteries serving trailer refrigeration and heating units by preventing battery depletion during periods of inactivity without overcharging them by maintaining only a shallow depth of battery discharge, which helps extend battery lifespan. The durable 10-pound device is rated for exterior mounting on the trailer body and is engineered to operate whenever the tractor is connected to the trailer by using the trailer’s existing seven-way cable, eliminating the need for extra charging cables. The charging system’s logic controller includes a low-voltage disconnect that helps protect tractor batteries and is programmable to any LVD setpoint. The unit is built to handle harsh road conditions with temperature-compensated charging that automatically optimizes its charging characteristics to match its operating climate. LED status indicators display that the unit is functioning properly and alerts for any issues.