18650 BATTERY CELL 3.7V 1000mAH RECHARGEABLE LI-ION LION BATTERY Model: TR 18650 Standard voltage: 3.7V Rated Capacity:1000mAh Diameter: approx 18mm Height: approx 65mm Applications.. Arduino power supply, Robotics, Toys etc. Description: No, these aren’t some sort of weird, AA battery, this is actually a 18650 Lithium Ion Cell. These round high capacity cells have been mainly used in flashlight type applications but with its capability to be used as a drop-in rechargable cell at 3.7V with a capacity of 1000mAh. This is a great battery option for those of you who need a simple to install and replace cell with a lot of juice. These 18650 Cells have a standard discharge current of 0.2C to a maximum of 1C and can handle about 300 charge cycles.