The current maximum of 18650 battery is Panasonic 3400 mA.
18650 battery is used in notebook computers, equivalent to 2 sections of CR123A battery size, so it is used in more flashlights.
26650 battery is currently the domestic capacity of 4000 mA, but the volume is much larger, the only advantage is that the discharge current is larger, 26650 battery is the best partner of torch, other electronic equipment is rarely used, 26650 battery application popularity is not high.
1 # batteries and 5 # batteries, 1 # batteries are mainly used for flashlights, and 5 # batteries are used for many electronic devices.
18650 battery was first mainly used in notebooks, and it was widely used in the field of consumption. So the battery used in making the flashlight is also a large number of off-the-shelf batteries.