The 3.5 amp Genius G3500 is one of a new line of “wicked smart battery chargers” from Ohio-based NOCO. For use with 6- and 12-volt batteries, the battery charger features NOCO’s Rapid Charging Technology to charge batteries twice as fast as standard linear battery chargers. The Genius G3500 fully recharges and maintains batteries to their original capacity and is safe for wet, gel, MF and AGM-type batteries. Five-year warranty. $74.95.