Poorly performing FandyFire STL-V6


I just got a FandyFire STL-V6 (from Wallbuys) late last week, and while it seems that this is an older light, I had great expectations for it as far as throw and lux. I had posted in an older thread about it, but I thought that I’d start a newer thread to try to address primarily the performance problem.

There is a “functional” oddity with the STL-V6 that I got, i.e., I can’t get it to switch into the 3-mode group, and between that and the disappointing lux numbers, I’m starting to suspect that maybe there’s something different (and worse) about my STL-V6 vs. the ones that others got before.

I’ve been doing lux measurements, at 4.3 meters, and the numbers I’m getting are 1/2 or less than those that I get for an HD2010 (with the original EAST-092/direct drive driver). For all of the tests that I’ve done with the STL-V6, with different batteries, including pairs of fairly new, freshly charged Efest IMR batteries (4.20V), are coming in around the 1500 lux ( 4.3 meters) range.

So, I was wondering, if anyone has an STL-V6, could you tell me if the driver board on yours at least looks like mine:


P.S. The mode group thing also is bothering me, so if anyone has any ideas about that, please let me know?

Edit: BTW, can anyone tell me how to convert that 4.3 meter lux reading to 1 meter lux reading?

Up at the end of the tube (closest to the head) you just tighten and loosen it slightly and you can change between 3 and 5 mode. Meaning the joint connecting the tube with the head essentially.
Tighten for 3 mode, loosen for 5 mode.

Thanks for posting!

I’ve tried that, multiple times, even with nitrile gloves (for better grip), and it’s not changing groups.

I just found this:


I think that the thread is about the same light, albeit in 2011, but in the 3rd picture in post #3, there’s a picture of the driver end of the pill, and that looks different than the pic that I posted :(… which might explain both the bad performance and the lack of mode groups.

Does anyone here still have one of these lights? Can you check how your light/driver end looks, compared to the pic that I posted?



Hmm. I just found this thread:

In post #10, “willie” said:

I had measured tailcap current on my STL-V6, and I’m also only getting slightly more than 1.5 amps (with 2 x 18650), so it almost sounds like I got a FandyFire STL-V6 but with a MarsFire driver (my light only does 5 modes).

That might be true…

Also, I can’t take the retaining ring off my tail cap right now because I can’t find my tweezers. But mine does have 3/5mode and 3A high.


Thanks for responding and your help!

Can you tell me approximately how long ago you bought your STL-V6? And, also, from where?

FYI, I just wrote an email to Wallbuys explaining what I’m finding.

Please advise, and, again, thanks!


I bought it close to a year ago off aliexpress. I can’t remember the seller but I remember it had a picture of a native american shadow type thing.


BTW, the picture I posted, and what I’m asking to compare, is not in the tailcap.

Rather, it’s the spring-side of the driver, inside the head. So, you just have to unscrew the body from the head, and look at the spring side and compare that to the picture that I posted in the OP.

Pls advise.

Thanks again!


Woops, will check now. I was wondering why you’d have a picture of the tailcap… LOL

4.3 squared = 18.49, 18.49 * 1500 = 27,735 candela, or 27.7 kcd. Formula is distance squared times the lux meter reading.

Yes - that is disappointing in throw, but if you are reading 1.5A, then you effectively get 3 amps to the LED. Batteries are in series so the voltage doubles. dunno, maybe something weird with te driver or major problem with the emitter.

Hi Tom,

Ok, thanks for the formula!

I’m curious to see what slewflash finds when he compares what I have vs. his STL-V6. There’s a pic of “the” STL-V6 on the thread I linked earlier, and it had a pic of the STL-V6 driver which was different than the one I posted in the OP.

I’m hoping slewflash’s looks like the one on that other thread :)… that would be definitive that the light I have has “the wrong” driver…


Slightly off-topic question: I’ve seen comments that the STL-V6 can be turned into a 1x18650 light, by using a C8 body. I have a bunch of C8s, from different places, but none of my C8 bodies fit the STL-V6 head, because the C8 bodies are much smaller diameter?

Was it only certain C8s worked with the STL-V6 head?

Mine looks different to yours, the picture is here. I’m not going to embed it since the picture is quite large.

Just an FYI, mine was branded SkyRay STL-V2, but they should be the same as the FandyFires.

GREAT!! Thanks! As I said, I think that this is pretty definite “proof” that the STL-V6 that I have has “an incorrect” driver…

slewflash, thanks a LOT for your help! This has been driving me nuts all weekend, and my hands are still sore from trying to tighten the body ojn that light :)!


Edit: BTW, your picture looks similar/the same as the 3rd picture in the OP in this thread:


which is, apparently, “the real” STL-V6 driver.

No problem!

ohaya, I’m pretty sure yours is not the 3/5 mode version. If you look at the driver end, it does not have the means to detect the tightening/loosening action. On the STL-V2 there is an isolated ring on the driver, which makes contact with the body when tightened. That is how it chooses the groups.
Yours looks like a TR-3T6 style head, not groups.
Also, the throw numbers you are getting may be disappointing, but they are pretty much right on for a stock TR-3T6 style light (mine came driven at 1.5A on 3x18650 too). Throw was in that ballpark as well, until I modded it. It’s somewhere in the 35-40k range now.
Based on what you have in hand (not what you expected), the light seems to be working as it should.
Does it need a mod? Hell yes! :wink:

And going backwards with regards to flashlight release dates can be underwhelming. I got a skyray triple 2 x 18650 after I had already got used to a(n) SRK. The driver on the triple is showing close to 4A but it pales in comparison to the king. That said, its still a nice light.


Thanks for that info, but I bought a FandyFire STL-V6 from Wallbuys:

and, while I may be being naive, or stubborn, or both :), I expected to receive a FandyFire STL-V6, with “2 group”, and not a TR-3T6.

BTW, I just checked, and isn’t the TR-3T6 a triple emitter light? The one I have has only 1 emitter. Also, the one I have only has room for 2 x 18650, not 3 x 18650.

I’ve gotten some response from Cherry at Wallbuys, and am trying to see how they can resolve this (hopefully with a real STL-V6), and the info that yourself and slewflash will be helpful with that, I think.


Hi slewflash, relic, et al,

I wanted to be clear that (1) I appreciated your help with this issue very much and (2) I am not just disregarding what you said, but as I said, I feel that Wallbuys describes the light on their website with the mode groups, etc., and I feel that they should provide what they describe.

Again, thanks for all of your help!


P.S. FYI, Cherry has requested a video demonstrating the problems with this light, which I’ve made and provided a link to the video to her (it was too large to email), so hopefully, with that, plus the emails, and the info in this thread, which I referenced with her, she has all of the info that she needs to resolve this problem.

If you’re supposed to have a 2 group driver but don’t….then I don’t see how they wouldn’t help ya out!

Good luck!