Features 1、MAIN PURPOSES: Car DC to DC charger can charge the main living battery through the car generator and starting battery, or the main battery can be charged by the solar panel (some models). 2、AUTOMATIC CHARGING: In order to continuously charge the battery, the controller can always connect the car battery. When the charging energy stops, the battery will not discharge in reverse direction. 3、MULTIPLE PROTECTION: The automatic battery charger has overheat, overvoltage, short circuit and wrong connection protection to ensure safe and reliable operation. 4、AUTOMATIC WAKEUP: When the lithium battery BMS is protected for some reason, the controller charger can automatically wake up the BMS and continue to charge the lithium battery. 5、APP CONNECTION: An external BT module (not included) can be connected, and mobile APP can be connected to the charger to display various charging parameters, historical data and fault information in real time. Specifications Item Type: DC to DC Battery Charger Product Size: Approx. 23.5 x 19 x 7.2cm / 9.3 x 7.5 x 2.8in Material: Aluminum Alloy Main Battery Voltage: 12V Main Battery Type: GRL, sealed acid, AGM, lithium iron phosphate, ternary lithium battery Starting Battery Voltage: 12V Maximum Charging Power: 390W Maximum Charging Current: 30A Standby Current: 24mA Purpose: Solar Controller Weight: Approx. 1500g / 52.9oz Package List 1 x Battery Charger 1 x User Manual