He’s using 4x meco protected 18650. :person_facepalming:
But they are the best at 4000 mAh! Seems like these high performance lights need high performance cells, even with all that buck/boost stuff on there - oh well. 
:FACEPALM:
Protection kick in? Meco is definitely not a good match with this light. :FACEPALM:
Able to take the voltage with the batteries loaded in the carrier?
Boy, I recall back in 2011-2012 when just getting started in this hobby, I figured I'd order the best cells around. The most expensive ones are the best, right? So I ordered 4 EagleTac 18650's, protected. Wow, these were the poorest performing protected cells I ever had, even compared to UltraFires and TrustFires. The EagleTac's were wrapped Pana A's, 3100 mAh, which are bad enough, but their added protection circuit has gotta be one of the worse.
I read on Lexel’s thread that each of the three groups of LEDs is 2S3P
Even if there was a dodgy LED in the group, I would still expect the other two parallel pairs in the group to work. So I could understand 2 LEDs being out in the group, but not all 6.
So I still suspect a dodgy driver (doesn’t match the other 2 at lowest level), not the LEDs.
Edit: just saw “He’s using 4x meco protected 18650 (link is external). Facepalm” appeared whilst I was writing. Doh!! So ignore my wild speculation about the latest video (now deleted, strikethrough didn’t work ?).
I still think my theory about the 1/3 group not lighting up at lowest level might have some merit.
Just want to make sure that I do everything right - so you’re saying I should leave the tail cap off, connect the probes of the DMM to the + and - of the inserted battery carrier, switch it to the same setting that I normally use to check the voltage of individual cells, and turn on the light in the highest mode to check the reading?
Without thinking too much about it I thought he was using high drain Olight cells…
definately battery problem
Well, I passed along the information about those cells and it’s probably their protection circuit kicking in to the poster of that video.
If that’s the problem, then it’s not a problem with the light itself. That would be good news.
I really don’t know how this battery performs and don’t plan to buy some to further investigate 
At least one of the problems with his “faulty” flashlight is due to the batteries : “the turbo mode does not work”.
Most likely the cause.
Even assuming brand new protected cells in perfect condition, and all four fitted, with high-current protection circuits, and all four cells load-share evenly, it would be right on the edge. Even if over-current didn’t trip the protection, under-voltage of a high ESR cell drooping under load would take them out.
A true under-voltage would be expected to switch on protection solidly. Requiring a suitable charger to re-set it afterwards.
Bottom line, expecting to get 3000 lumens per 18650 requires top-notch un-protected cells. Worth making clear to prospective purchasers.
Those protected Meca are $3 each and have a 4000 mah rating. Do we need to investigate any further? Lol
[quote=Tom Tom]
They write
They should add, that high-Current Cells are a must, indeed.
That guy from the video can be happy that the protection-circuit works.
Otherwise that could go very very bad…
3$ batteries in such a light… oh me lord
Received mine today.
Holy shit!! This thing blows my Supfire M6-2 away! 
Really one impressive photon bomb.
+1
If batteries have protection try with batteries without protection
If batteries have protection try with good batteries without protection
What happens with cheap chinese batteries in High-Current applications can be seen multiple times if you search on youtube for “e-cig explodes”.
I don’t want to see a video with 4 exploding cheapo-18650s in a closed flashlight!
[quote=L4M4]
+1
+1
Most problems with new flashlights are caused by battery protection circuits
A good battery of good brand and good chemistry without protection circuit is the best choice
Yes!
I apologize
That little word make the difference, its absence can be catastrophic
[quote=L4M4]
Yeah, it’s always tempting to go cheap on the batts, after laying out a good bit of moola for a light. Which, is why BG spec’d high quality branded (Samsung), unprotected high-drain cells.