Components in these charging systems are completely sealed in waterproof thermal epoxy to prevent damage and corrosion. Three-stage charging cycles for fast recovery, overload protection with automatic resets, LEDs to indicate charging status and "Smart" technology to prevent battery damage even when the charger is left on. All models can be left on for maintenance during storage. Use with any battery type, even gel cells and 12-, 24- or 36-volt systems. Consult the chart for amp ratings and number of batteries. Serious outdoorsmen know the value of keeping their deep cycle and recreational vehicle batteries charged. The 2613 is a hard-working unit at an affordable price. You'll get a solid 15 Amps of charging power from three charging output cables that will charge either three 12-volt batteries or a 12+24 volt system. Charges flooded, gel and AGM batteries. A maintenance mode protects batteries from draining or losing charge during storage. A waterproof housing protects internal electronic components.