You could probably find a 26650 light which tube fits for increased runtime. Or just buy better batteries. This light should run two hours or so….
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I had issues with electrical connections between tube and pill, it sometimes changed modes on them-self…
I added a piece of wire which solved this issues perfectly. Just drilled a hole in the ring and bend a piece of wire in form…
(I would post a photo if imageshack wouldn’t suck right now…)
Another hint the AR coated lens for srk from cnq fits this stlv6.
For the other light which you call 3x 18650 hd2010.
This is well known here: