So I bought a <5mW laser from ebay. I did not expect something so amazing, but when I tried some cheap 1.2v Ni-Mh Batteries I has lying around, it proved to be worse than those red lasers they put on everything. A bit of research seemed to suggest a couple of 1.5v AAAs could only be an advantage, so I tried out these philips batteries instead and it was wow! I could see the beam and it was going 100's of metres and still lighting up clearly. This excitement was short lived though. It began to dim and the excitement was gone. I tried again a bit later and it was decent for a bit, but then it would dim again. This morning, the batteries are at 1.5v and the lasers strength is dismal. I also tried some 1.2v eneloops, but still pretty weak. What on earth is going on here?