BlackDecker said:
Like Brighteyez, I have not had a single problem with my 4AA SL ProPoly Lux. Lights up everytime I press the tail switch. Have noticed some battery rattle, but it's not a light I take jogging... I save that for the Sam's Element with the tightly packed 3AAA carrier. No rattle with that light.
After using the light daily for several months, i.e. turning it on and off hundreds of times, I've experienced exactly two failures to turn on. Both times, a light tap to the body of the light fixed the problem.
That is a failure rate of some small fraction of 1%. An issue that occurs this infrequently is hard to diagnose and troubleshoot, but I suspect it is due to battery misalignment.
If turn on failures occured more frequently, I'd try to fix it by inserting a thin piece of cardboard or similar down one side of the battery compartment to prevent the batteries from slopping around.
The battery rattle on my light can be annoying. If carried in the long tool pocket in the thigh of my carpenter jeans, the batteries audibly clank back and forth with each step.
I'd guess that Streamlight oversized the battery compartment to allow the light to take slightly out of spec, oversized cells from el-cheapo manufacturers. And, to make it easier for swollen or leaking cells to be removed without jamming.