The GENM1 mini on-board battery charger is a rugged and compact waterproof charger for 12-Volt lead acid batteries. It can be mounted onto virtually any vehicle, like a boat, car, tractor, or RV. Safe to leave connected indefinitely, the GENM1 interactively diagnoses, recovers, and charges wet, gel, mf, and AGM batteries chemistries from 20-120AH and maintains all battery sizes.