Those UltraFire batteries you linked to are not protected, and they're a fire. .. 18650's can vary in size by a few millimeters, some may have .
Most consumers are familiar with the omnipresent A, AA, and AAA battery sizes, but many of the same consumers do not understand the meaning of other battery size terms, such as the 18650. Manufacturers produce the lithium ion 18650 at a size of 18mm by 65 mm.
All 18650 batteries guaranteed Grade A.. The 18650 (18mm by 65mm) battery is a size classification of lithium-ion batteries. If you have ever held one in your .
I have made a new battery test: 18650 battery test 2011. A 2012 test. This graph shows the measured capacity for each battery with different loads. One thing. Size: diameter: 18.7mm (Mostly 18.4, but it has a bump), length: 68.3mm. Source:
That is because inside is a smaller battery with step up circuit which wrap in layers of paper and stuffed inside a 18650 battery size case then heat shrink in a