Fixed! Seems to be operating properly now. Quick clean of inner tube and inside of outer tube, inserted inner tube to a point with o-ring seated and very high resistance (55 M ohms) between the tubes, installed the tail cap, and inner + tube to outer reads open on the 60M range.
At this point I am very satisfied with the fw21. The only suggestion I have is a groove at the inner edge of the head end of the outer ground tube for an o-ring to help maintain no-contact space between the outer body ground tube and inner tailswitch + tube. Anodizing may be good for insulation but it’s not perfect.
Just reviewing the FW21 for my channel now, complete fail of a light (Lumintop recommend 10A> unprotected button tops, none fit lol) and Lumintop won’t answer my messages which furthers the misery of this project.
If it was my light, I would simply stretch the tail spring to make it longer. Or maybe swap in a longer spring. Or add a solder blob on to the button top. Easy fix.
it says on banggood the current batch does not fit flat tops unprotected like fw3a… so the question is , why did lumintop sent that batch to banggood? kinda useless if normal 21700 unprotected suddenly are too short… this is something u shouldnt have to worry about.
About longer tubes…
I have also first batch from BG and I wrote to Lumintop if I can get shorter second batch tube and they told me that tube is the same on both batches but second one has longer springs.
So they recommend me to swap spring for longer one.
Ive swapped the tail one for spring from led4power and all cells now fit perfectly without rattling and poor contact