This 12V 30A DC to DC charger tops off an RV, truck, or boat's standby battery straight from the vehicle's alternator while driving, working with lead-acid, lithium, AGM, GEL, and flooded batteries across an 8V-16V input range. It automatically selects the right charging profile: a 2-stage curve for LiFePO4 and a 3-stage bulk/absorb/float curve for lead-acid, delivering up to 375W to fully charge the standby battery without overcharging. Isolated input and output keep the vehicle's electrical system free of interference, while over- and under-voltage, high temperature, and reverse polarity protection guard against faults. The aluminum alloy case weighs just 2.65 lbs and comes with pre-drilled mounting holes for an easy install anywhere in a rig. Its lithium activation feature can also wake up an idle or deeply discharged battery, bringing it back into service.