Li-ion Battery
The 18650 battery is a lithium-ion cell classified by its 18mm x 65mm size, which is slightly larger than a AA battery. They're often used in flashlights, laptops, and high-drain devices due to their superior capacity and discharge rates.
Both 18650 and AA batteries are cylindrical batteries that differ in size and that come in various types of battery chemistries, thus differing in the battery voltage, capacity, and other charging/discharging characteristics.
The 18650 battery has a voltage of 3.6v and has between 2600mAh and 3500mAh (mili-amp-hours). (Osborne, 2019) These batteries are used in flashlights, laptops, electronics and even some electric cars because of their reliability, long run-times, and ability to be recharged hundreds of times over.
No, you cannot charge an 18650 battery using an AA charger. An AA battery has a voltage of about 1.5V, and it has a 2V cutoff voltage. This charger will not work if it reads anything more than 2V.
18650 Rechargeable Li-ion Battery: These are larger in diameter and in length than a standard AA battery size. The 18650 Li-ion battery is an extremely popular battery source for today's flashlights since the 18650 battery carries so much power.
18650 batteries are lithium-ion batteries. They get their name from their size: 18mm by 65mm. These batteries are not only used in flashlights, but also in: power tools, electric vehicles, vaporizers, cameras, laptops, and more!