If you haven’t yet done what i’m about to write, try it, it usually helps with my sc52.
Unscrew the tail cap, now clean the silver ring around the tail end of the body on the main tube with Nothing else! But a clean rag or toilet paper on a hard flat surface, don’t use any cleaners or chemicals as that may leave some kind of a residue.
Now the same ring within the tail cap around the spring should be cleaned with toilet paper or a cotton bud but the same again no chemicals or cleaners.
I usually find that alittle grease has gotten on them and cleaning them once in a while helps ALOT with brightness and settings.
This is another one of those times that I’m sad BLF doesn’t have a “like” button.
It’s helpful to eliminate sources of resistance along the electrical path. 
Thanks for that too. I will keep this in mind.
dave
My mate oddly fried his one with 14500´s…
Oh crap, thats too bad. I will not be taking chances now. Thank you
The SC52 officially supports a 14500 battery. The only time I've seen one fried with a 14500 was when the battery was inserted backwards. (There is no reverse polarity protection)
Okay, again. I didn’t know that it didn’t have reverse polarity protection. So, I won’t be putting a battery in this thing in the dark again then. Thanks again, it seems this was important and I should have known this about the light. Well, thats why im learning I guess.
dave
wow this light seems easy to be fried with wrong polarityl…i think i need to be a little careful with the installations