Why don’t you order from a reputable dealer in the USA? Guaranteed my hometown dealer has real ones. I have been buying my 30Q off of him for a few years.He has a good reputation and great customer service. A group Buy set up by Robert B. was done last June.
This is for BT’s he also has FT’s. They are ONLY $5 and you will know that they are genuine.
So you order all your shit from USA???
I don’t order shit. I get genuine and quality merchandise.
never mind
Oh well, I remember FT used to sell pink Samsung INR18650-30Q printed on shrink-wraps before….( I just checked and they are gone at the moment)
Have bought about two dozen 30Q’s from both BG and GB. Flat-top and button-top. Never had any problems.
For 1S charging I can't see anything at all wrong with a "dumb" charger. By "charger" I assume it's something current limited. So long as it's also voltage limited to 4.2V then you're 100% all set. A time cuttoff (wall timer) wouldn't hurt, but leaving it on for 12 hours won't hurt anything, and I'm unconvinced that even a couple of days will. I use my current and voltage limited supply to charge batteries with no problem.
I particularly like that little ~2buk one at FT. Forgot the current output, only a coupla hunnert mA tops, so overnight is no problem.
Wanted to keep a LK-100B with me in my bag, but that one (AC) or one of the small Thorfire/Sofirn chargers (USB) are lots more compact.
Today I had the same thing happen with my Convoy C8 (old 2-group driver). Bought it last year, not heavily used.
So it was in MED mode, and suddenly stopped working, no LVP blinking at all.
The cell was checked below 1.0V… an old laptop pull, but was working fine before that.
So I tried another fully charged cell. LVP kicked in at 3.6V. Strange. Then I put the light off and on again. Next LVP blink came at ~3.3V.
At that point I verified the C8 and tightened the driver retaining ring (was not loose but I could tighten it a bit).
Now testing with another cell to see a difference. Maybe the driver is toast? 
It sounds like the LVP is working as the you said by verifying with the 3.6 and 3.3 V reading. What you are not allowing for is the voltage drop of the battery under load which is with the torch turned on.
Your batteries may well be past there use by date.
But the LVP is supposed to come at 2.9-3.1V according to Convoy specs.
An older cell would do that?
Looks like an occasion to put a more reliable driver in this one 
An old cell with a resting voltage of 3.6v or 3.3v, might very easily drop to 2.9v when you put a big load on it (like a Convoy on max).
Most cells don’t have much energy left in them by the time they’re down to 3.3v resting. I usually charge mine up when they get down to 3.7v, which is usually under 50% full. On a light that doesn’t use a boost-driver (such as a Convoy), it also really helps to have a mostly-full battery to get full output.
Thanks for the explanations. I will also make sure to check my cells before use in this light.