This is a automatic DC-DC charger that can charge the main battery through the and starter battery, or Solar panels charge the main battery (some models), DC-DC battery charger designed specifically for motorhomes, campers, ships, etc.

Function * Microprocessor Control (CPU). * This is a fully automatic battery charger * Automatic charging protects your battery from being overcharged. So you can leave the charger connected to the battery indefinitely. * Smart chargers are suitable for most battery types including Calcium, Gel AGM, Wet, lead Acid batteries. They may also help restore drained and sulphated batteries. * Types of batteries: Most types of lead acid batteries including Calcium, Gel AGM, Wet, lead Acid, LiFePO4,etc.. * Switchmode technology: Yes * Polarity protection: Yes * Output short protection: Yes * Non battery link protection: Yes * Over voltage protection: Yes * Over temperature protection: Yes * Cooling: Fan * Input voltage: 100-240V AC, 50-60Hz * Rated output: 12V 7A max. * Minimum start voltage: 8.0V * Battery range: 4-140Ah * Thermal protect: 65'C+/-5'C * Efficiency: App. 85%. * Compliant standards: CE, UKCA, FCC * Dimension (L×W×H): 158×85×63mm * Weight: 440g