I am just returning to the forum in an active fashion after a wonderful ski season. I have been commuting throughout the winter just my internet concerns were those of skiing.
I offer this as an apology if my following concern has been addressed in the 15 or so pages of this thread that I have missed.

I have two P7 (5 modes) that I use for commuting: one helmet mounted and one on the handlebar. I use them both on high and have fabulous lighting for my dark rides (often both in the morning and the evening-long days)......My helmet mounted one is having a small problem. If I screw the back all the way down the light won't work. If I loosen it a millimeter or two then the light works. I know, I know, just loosen it but I worry when it is wet out. Am wondering what might be wrong and how to fix it.......In my very limited understanding of electronics usually the connection is affected when things loosen rather than when the connection is too tight?

Thanks,