The answer upstairs is 18650. The questioner should ask about the difference between 18505 and 26500. Let's take Fuant ER18505 and ER26500 as examples. These column batteries are non-rechargeable lithium batteries, and the voltages of both are the same. is 3.6V. The difference is that the volume is different. The first two numbers are the diameter and the last three numbers are the height. The larger the volume, the larger the capacity. is 4000 mAh and the capacity type ER26500 is 8500 mAh.
Dangerous, definitely not possible, it would immediately fry the flashlight circuit or cause battery problems. The reason is that the full charge voltage of the battery is very different: the voltage of each AA battery is 1.5 and that of 3 cells is 4.5V, while the voltage of a lithium battery reaches 4.2 V and that of 3 cells is 12.6 V. Second, even if the voltageof a single lithium battery is similar to that of three AA batteries, the discharge current is different from that of AA batteries. A special protection circuit must be equipped, otherwise the main part of the lamp head will be burned. , or the battery will be discarded due to over-discharge. Finally, it could be a hardware error. The appearance of the 14500 lithium battery is the same as that of AA dry batteries, while the 18500 lithium battery is smaller.