Meet the NOCO GENIUS2D, one of our most powerful, highest-performing, energy-efficient, and compact onboard universal battery chargers yet. The GENIUS2D is a 2-amp (28-watt) - 100-240VAC 50-60Hz - 12-volt heavy-duty battery charger, battery maintainer, trickle charger, float charger, and battery desulfator for up to 40 amp-hours. It's designed to charge and maintain all types of sealed lead-acid batteries, including flooded, gel, maintenance-free, AGM, SLA, VRLA, as well as automotive, marine, RV, powersports, and deep-cycle batteries.