The Millertech Dark Speed 12V-36V On The Run Marine Charger keeps your auxiliary lithium batteries charging directly from your vehicle's alternator while you're in motion, powering trolling motors, fish finders, and electronics without relying on shore power or generators. A smart monitoring system prioritizes the starting battery first, then diverts power to your auxiliary bank at the correct voltage for 24V or 36V systems. It also features an automatic BMS wake-up for depleted lithium batteries. Built with marine-grade waterproof housing and equipped with safeguards against low voltage, overheating, and over-voltage, the Dark Speed charger provides efficient, safe charging that extends battery life and maximizes time on the water. Input voltage: 90-130V AC AC power draw: 857W Output voltage 1: 14.5V 15A Output voltage 2: 42.6V 15A Start transfer voltage: 14V Stop transfer voltage: 13.3VCharges lithium batteries from vehicle alternator while running Smart monitoring prioritizes starting battery before auxiliary banks Automatic BMS wake-up for depleted lithium batteries Marine-grade waterproof construction with built-in safety protectionss Eliminates reliance on shore power or generators Manufacturer's three year warranty