The GEN Mini On-Board Battery Charger is a rugged and compact waterproof charger for 12V lead acid batteries. It can be mounted onto virtually any vehicle, such as a boat, car, tractor, or RV. Safe to leave connected indefinitely; the GEN Mini interactively diagnoses, recovers, and charges Wet, Gel, MF and AGM batteries chemistries from 20-120Ah and maintains all battery sizes.