The first number in the product name indicates the maximum voltage that can be connected to the PV input of this controller with a (series) solar panel. The second number indicates the maximum regulator charging current at 12, 24, 36 or 48 V depending on the regulator type. There are controllers for 12/24 V, but also controllers that can also charge 36 V and 48 V battery banks (see manual).
Load output: Over-discharge of the battery can be prevented by connecting all loads to the load output. This output disconnects the load when the battery is discharged to a preset voltage. Alternatively, an intelligent battery management algorithm can be selected: see BatteryLife in the manual. The load output is short-circuit proof. Some loads (especially inverters) are best connected directly to the battery and the inverter remote control to the load output. You may need a special interface cable. See the manual for this.
BatteryLife: intelligent battery management If a solar charge controller cannot fully recharge the battery in one day, the result is often that the battery constantly fluctuates between 'partially charged' and 'fully discharged'. This condition (not regular full charging) will irreparably damage a lead-acid battery within weeks or months. The BatteryLife algorithm monitors the battery's state of charge and, if necessary, increases the load disconnect level slightly from day to day (disconnecting the load earlier) until the harvested solar energy is enough to drive the battery to almost full 100% to charge. From then on, the load disconnect level is modulated so that the battery is charged to nearly 100% approximately once a week.