So, this weekend I decided after a failed attempt around a year ago to try once again to build a laser using a Dealextreme 200mw green laser module. This time I decided to use a nice C6 host from survival lasers. Anyways, after assembling the laser it worked Perfectly. The beam was visible in a well lit room and it burned various things with ease (after focusing). The module was powered by 1 18650 cell instead of the 2 AAA batteries that I have seen used (I've heard it shouldn't be a problem). Anyways, the next day I decided to test the laser with some of the different 18650s and when I put one of them in (after successfully trying another one) the laser power dropped significantly. The beam was no longer visible in light and the dot of the laser had also grown slightly (half an inch in diameter at 20 ish feet). So I thought it was the specific battery I tried but when I swapped back to previously working batteries the same thing occurred. I'm wondering if maybe I left the laser on for too long while swapping batteries and maybe it overheated? Or if there is another problem (maybe fixable?) that could explain these symptoms. I disassembled the laser and nothing appears to be different than before. I was really excited about my first successful laser build however it seems it has only lasted one night Any help is appreciated.