With the intelligent battery charger, up to four NiMH batteries of sizes AA and AAA, three C batteries, two D batteries, or four Li-Ion batteries of size 18650 can be charged simultaneously, even in mixed combinations - regardless of quantity, size, capacity, or charge level. Each of the four charging slots is monitored and charged or discharged individually. Once a battery is inserted, the charging mode starts and fully charges the battery. Each battery is charged separately, allowing batteries of different types, capacities, and charge levels to be inserted and charged or discharged. After full charging, the charger automatically switches to pulse maintenance charging, keeping the battery charge at 100%. This ensures that the batteries are always ready for use and can remain in the charging station for extended periods. After full charging, individual battery cells can be removed and new ones inserted without affecting the charging process in the other slots. Incorrectly inserted batteries and deeply discharged batteries are detected. For professionals, the device offers the option to individually set the charging program and charging current for each slot. The Mode button allows you to select the charging mode, while the Current button adjusts the charging current. The currently selected setting is indicated by an arrow. If no settings are made, the charger operates at 500 mA. If you need a quick charge, three batteries can be charged at 1500 mA or two batteries at 2000 mA, reducing the charging time accordingly. Additionally, the charger can measure capacity and discharge batteries. Whether you want to charge NiMH or lithium-ion batteries, the charging currents can be selected as follows: 4× 500/1000 mA, 3× 1500 mA, or 2× 2000 mA. The discharge current is always 500 mA. The universal charging slots can accommodate battery cells with a diameter of up to 33 mm and a length of 70 mm.