Question: are there different size aaa batteries?
Answer: At first, AAA and 18650 batteries don't have much in common - AAA batteries are cylindrical batteries 10.5 mm (0.41 inch) in diameter and 44.5 mm (1.75 inch) in length, while 18650 batteries are cylindrical batteries 18.6 mm (0.73 inch) in diameter and 65.2 mm (2.56 inch) in length.