The MCUO36 charger is designed for charging single 12 volt lead acid (starting) batteries widely used in motor vehicles, motorbikes and marine craft. It will also charge deep cycle batteries used to power ride-on mowers, jet skis, golf buggies, etc. The batteries are often referred to as WET CELL, GEL or AGM with capacities ranging from 12V/1.2Ah to 12V/120Ah (or up to 750CCA). The charger will NOT fully charge calcium-calcium batteries. The charger is NOT to be used as a power supply or for any other application other than charging and maintaining single 12 volt lead acid batteries. NOT TO BE USED ON NON-RECHARGEABLE BATTERIES. In all applications you must NOT connect the charger to mains power until battery connection has been completed. Prior to disconnecting the charger from a battery, you must FIRST turn off mains power supply at power point. WHAT DOES MCU STAND FOR? MCU stands for (MICRO CONTROL UNIT) meaning there are different stages of the charging process: 1. Diagnosis & Recovery 2. Two Stage Bulk Charging 3. Absorption Charging 4. Float Charging 5. Maintenance Charging These different stages enable the battery to be recharged to almost 100% capacity. The charger can remain connected to the battery indefinitely without any damage being caused to the charger or battery.