The ARE-D1 Battery Charger from Fenix Flashlight has a single bay to charge nine different types of li-ion, NiMH, and NiCd batteries. The included micro-USB charging cable plugs directly into the charger and then to an external power source. During the charging process, the LCD screen displays the voltage and status of the battery, and you have the option of selecting the number of amps being used to charge the battery. The charger can also discharge a battery completely if the need arises. The smart charger has built-in protection against over-current, over-voltage, short-circuit, and reverse-polarity. It automatically regulates the charge to extend the life of the battery as well.