More than a 30 amp car battery charger this unit features 80 amps of engine starting power. That's enough to get most vehicles going when you get caught with a dead battery. Even charge personal electronics with the 3.1-amp USB charging port. This multi-bank car battery charger can handle two batteries simultaneously and it also features an Alternator Check function to help diagnose vehicle battery issues. Check battery voltage anytime and help revive an old battery with the Battery Recondition function. Reverse polarity protection prevents improper connection.