ITEM NAME:18650 Battery Charger 26650 USB Smart 21700 Single Slot Lithium Battery Charger.Lithium battery 3.7V-4.2V or a nickel-hydrogen battery 1.2V-1.4V. 3.6V/3.7V Li-ion: 3.6V/3.7V-4.2V lithium battery. It can be recognized that the battery is a. 1.2V Ni-MH/Ni-CD: 1.2V-1.4V NiMH battery.