My WT90 led glows too when off, it goes away when I unscrew the tube. But it is so weak that I expect it to be 1 micro-amp or something, anything in the construction or driver can cause that. No worry at all in my case.
the reflector slightly shorting the ground wire would make sense, can anyone verify what TA asked above? I will check for this if mine is doing it when i get it.
That would actually worry me, but way more likely is a tiny leak under the led, between the led-minus pad and the center pad, perhaps the used flux is not a perfect insulator.
Yeah, some leftover flux makes more sense for a very slightly glowing LED.
Oh, well that'd be great if that was it. an easier fix for me than messing with the wires or a capacitor (?) or something else.
Just checked my WT90 and the LED glows very, very slightly. I removed the reflector and it still glows. I cleaned up as much as I could around the emitter (obviously can’t get under it without reflowing), and it still glows. Hoping someone wants to try reflowing their emitter cause I’d hate to desolder the emitter leads again for no reason…
@Tom E, what do you mean by resistor bank? I’m only familiar with the TA driver topology published here: https://budgetlightforum.com/t/-/41018
Some minor thoughts on the design and machining which are not complaints:
- It’s sharp, yet a bit slippery without any knurling. I know it’s unfinished and raw anodized, and I understood what I was getting into. Still, I found myself filing down some of the sharper corners and edges.
- I wish more flashlight makers indexed their body tube threads to align logos consistently. The Wildtrail name on mine is on the side and a little toward the back.
- Tactile rubber e-switch with press-fit rings like those offered by Emisar/Noctigon feel a bit more quality/satisfying than the WT90’s.
- The scalloped portion of the heat sink fins is very attractive. Art deco vibes.
- The middle pillar of the tail is shorter than the three legs. I think having it the same length would make tail standing more stable in most scenarios (maybe there’s some advantage of a shorter pillar for compliant surfaces?).
- I think the cell carrier should have some sort of emergency access hole at the top in case it gets jammed into the body. Imagine a bit of dirt getting into the gap.
Final update on the fake P42As: The seller told me their supplier “accidentally mixed in some sample cells with their order” 
. I’m keeping the cells (it is technically illegal to traffic counterfeit goods) and getting a refund. However, my MC3000 tells me that the cells’ discharge curves are spot-on compared to results from HKJ’s tests. Internal resistance is ~10 mOhm higher than nominal, but I’m not sure if it’s statistically significant. Bottom line is to stick to trusted battery vendors unless you’re willing to do deal with the potential trouble.
Without having to unsolder the emitter, you could unsolder the minus led-wire, it it glows after that, it is a leak under the led for certain, if it does not glow, it is something in the driver.
In either case I would do nothing, I do not see it as a defect or even as annoying if it takes years to drain the batteries (unlike my FT02, the parasitic drain empties the batteries in a week 
)
That’s a good debugging insight. Thanks for sharing!
Edit: wrote some stuff but deleted after I realized I misinterpreted what I read earlier
Sorry… it is a Defect and an Annoyance….it annoys me that I can not to recommend this light to my group of flashlight enthusiasts or anybody else because of the defect…. fix it and they will come…and buy…
Aweesome, thank you for the tip djozz
Why is that a big concern? In the end it is just an extremely low passive drain.
Whether or not it bothers someone is personal. Hard to say why we feel a certain way sometimes. My opinion is that it’s definitely an unintended feature, and it’s important we identify why it happens on so many lights so that we can make informed design decisions in the future. Could be worth fixing, could not be.
Do you have other lights that the LED glows… I don’t… they don’t…will it get worse as time goes by… or worse the more it’s used… would you worry if the lights in your house had a slight glow… headlights on your car… I just don’t want the head ache of explaining to people it just a minor passive drain… just saying… personally I mechanically lock out all of my lights…
i mechanically lockout too. And I had a low glow on a led canister insert 4" round light a contractor installed after a renovation. It was in my bedroom and I could see it every night. It really bothered me. Come to find out (after thinking it was bad wiring) it was a cheapie light, I bought a better one and replaced it and the problem went away. It did bother me though
I built a light for one of the guys at work Ray-Ray… it has an Led4Power lighted tail cap with LVP built in… the plant manager is having a conversation with him, when he runs off , across the plant and changes the battery because the tail cap was flashing. LVP kicked in… he runs back and explains to the manager why he ran off… then the plant manager had a discussion with me… to tell you how anal Ray-Ray is… he has an 8 battery charger… loaded… because he never wants to be with out… he is just one of many…
Just checked mine and it doesn’t have any LED glow
Mine has a green glob LED that can be seen even during the day and is always on and off when I turn on the flashlight.
…glow
The next most likely places for voltage leakage are the FET’s, could be the small or large one.
I use a resistor bank in place of the 7135’s for 2s or higher voltage lights, works the same way, it just replaced the 2nd bank of 7135’s but the resistor bank doesn’t care about the voltage
1: Yes, this is the downside to not beadblasting it, it does leave some sharper corners. If you do blast it then it removes all the machining marks. People seem to prefer the machine marks from what I have seen.
2: Trust me, they have all tried to index the tubes, it just simply doesn’t work. WAY too many variables to get the threads to always end with the correct alignment.
3: I try to stay away from press-fit anything whenever possible as it greatly reduces repair-ability/upgrad-ability down the road.
4: Thanks!
5: It is almost always more stable to have things stand on points at the edge then in the middle. Gives a wider base and makes it less effected by imperfections in the surface. The center being shorter was done on purpose with this in mind.
6: Apparently the carrier fits a lot tighter in the production version, this was not an issue in the proto. Worst case you can remove the battery tube and press it out that way.
I don’t have a light or I would test this myself, given the current things I am reading here. If it is not a leakage under the LED then I am going to guess the most likely cause is either the small or large FET on the driver or some excess solder flux.
First step would be to narrow down which channel the leak is coming from by removing each FET individually and seeing if the glow stops.
Once we know what channel it is, it should be fairly simple to figure out the problem.
My gut says it would be the small FET since I don’t think that the FET I used in the GT4 was in stock for that one so had to substitute another one with similar specs on paper.
I can see both sides to it, on one hand from a purely technical standpoint, while it is indeed out of spec the real world effects are minimal.
From an OCD point of view, it is unacceptable lol.
I can see both sides to it.
Wish I had a light to test right about now, I have a feeling the issue is a pretty simple one since the design is very very proven at this point.