So [Travis] decided to upgrade it to make use of the ever-so-common, 18650 lithium-ion battery. Not looking to purchase any components [Travis] performed this hack using simple recycled household ...

French researchers have announced a prototype of an 18650 sodium-ion battery. If you’ve bought a powerful LED flashlight, a rechargeable battery pack, or a–ahem–stronger than usual LASER ...

So, it makes sense that their 18650 batteries are among the top in vaping. This Samsung 25R (INR18659-25R) cell has a capacity of 2500mAh. It can output a continuous 3.6V with a full charge of 4.2 V.