greatscoot
Flashlight Enthusiast
The driver was updated a couple of years ago and it runs fine on a single 18650 (albeit at reduced output). I don't think the website has been updated to show this. There is a fair amount of info on this in the M91 thread.It's rated put 5.5 to 12 volts. I ran it on both 2x cr123 and a 18650 just to fiddle around and never had an issue.