That first video, showing the indicator led”s flickering, is just how my batch 1 Q8 behaved before the indicator leds died completely.
Light works fine but indicator leds dead.
It depends on the protection circuitry that was installed. Do you know what company added the protection circuit or at least where you bought them from?
This is only in reference to the factory flat top cells. If it has the added button top or raised flat top, then it is fine.
BTW, any flat top cell can have a solder blob added to raise the positive end.
Should be fine.
The protected NCR18650Bs are from here:
The description only says: “The PCB use 2*MOS protection board, maximum power voltage is 4.2V, the minimum voltage of 2.5V”
I have tested this (freshly charged) protected NCR18650B on Astrolux S1 (ie. BLF A6) and S2 (ie. BLF X6v2), they do not trip even when set to Turbo mode.
However, I just got the Astrolux S41S quad-Nichia, and when freshly charged, the said battery trips (turns on and immediately turn off) on Turbo and on High-2 modes.
Any idea what are the parameters/characteristics of the “2*MOS protection board”?
My INR18650-30Qs are the unmodded flat-tops. Maybe I’ll use the unprotected LG HG2s then…
Thanks for the response!
How many amps is the highest current draw of the stock BLF Q8 (I believe that’s being shipped is the newest revision)?
I don’t recognize those particular cells. Just saying “2 MOS protection board” isn’t enough information. I know the higher rated boards (8A to 12A) tend to use 3 mosfets, but without specific details we can’t say for sure what the max current is.
It says output is 600mA, but that might be a typo. If it said 6,000mA then that would be 6 amps and is about the rating I would expect.
From some quick searching I see that the S1 light can draw 4.5A on unprotected cells and maybe 3.5 using protected.
The S41 can draw 9 amps with an unprotected cell. I can’t find any data about the amp draw on High 2. I wish I could so we would get a closer idea of this batteries limit. I would guess that High 2 is maybe 5 to 6 amps.
So we know it can deliver at least 3.5 amps, but not 6 amps.
The Q8 on 4 cells can draw 16 amps with unprotected cells. So maybe 13A to 14A using protected cells. That is 3.5A per cell. You might be okay using those protected cells on the Q8.
Jason, if the cells won’t put out the amps the light calls for, it will still power the light just not at maximum output, correct?
That seems to depend on the way the protection circuit is built. The protected cells d_t_a linked to obviously cuts all power if the amp draw exceeds the added protection circuits limit.
Then there are other circuits that will limit output instead of turn off. On my L6 it will draw 17A to 18A with unprotected cells, but my KeepPower protected cells will simply limit the amp draw to about 10A instead of shutting off all power.
So it really depends on the added circuits.
To answer your question, let’s say you had protected cells that only had a 2A limit then it cuts power. Four of those in the Q8 would limit the total amp draw to 8 amps. You would still be able to use the light at lower levels, but once you ramp it up to about 3000 lumen the lamp will cut off. So it’s usable, but annoying.
One thing I will say is that these protection circuits always increase the internal resistance and on a fet driver they will always pull less amperage than the same cell without the protection circuit. Assuming the amp draw does not exceed the limit of the protection circuit.
Oh yeah, if I were running protected cells in a Q8, I’d make sure and get some that are tested to do at least 5A. That should be fine for a stock light.
Thanks. Understood.
Thanks for the detailed explanation, JasonWW.
I think my flashlight IQ just leveled up! 
I am using those:
Compared to 30Qs, the output is like 250 to 300 (lux @ ceiling bounce) , so I suppose it’s good 4,5k lumens.
Shall I ask BG for replacement LEDs/driver? Or someone here wants to look at it?
After a night rest, leds were good. But after 1hour green light began to blink again.
Are you referring to the batteries d_t_a linked to?
They do not appear to be the same. Different button top size, different button top ring, different sticker on side. I’m pretty sure the protection circuits where added by two different companies. Most likely different circuitry added.
I killed a cell doing this runtime last night, so everyone can enjoy my fuck-up. This is with GAs and thermal management disabled because I normally use it outside where it’s too cold to matter. Let’s just say it got rather hot.
Are you saying heat killed the battery Bob? I have done lots of testing with run time tests with thermal management switched of with 30Q’s in the Q8, yes the light does get extremely hot but I’m yet to kill a battery or damage any other components in the light.
I know, just posted an example of NCR18650B’s that works in my Q8 without problems. A little less light than 30Qs, but longer runtime.
I wonder what happened in the second Q8…. while problems with switch LEDs were happening already (though I got Q8 from the second batch, after September production stop), the delay in mode switch is pretty strange.
I’m not sure what happened, but one of the cells was dead after the test (reading 0.8V right now and dropping). They are new flat top GAs, but I haven’t had any issues with uneven drain. The light did get rather hot.
I had some liitokalas failing sone moths ago , out of the blue . They just turned 0.1V after one or two days after they were charged . One of them was inside a light (not a parasitic drain issue) , the other not . Still a mystery what happened…
The flat top 30Q’s that I had worked in my 2 Q8’s even before I soldered some 14 gauge wire (bent into a small circle) to the top of them. The only reason I added the wires was that I was concerned that the wrapping would be ripped off the top of the batteries when the body was screwed down. Solder blobs work just as well but I like the look of the wires so that’s what I always add to the flat top’s to raise them.
I made a diffuser out of a sauce bottle. After you cut the top off is is a push fit. Big W and Spotlight carry these in Australia. I also put a small convex blind spot
mirror in the bottom to block light from going straight out the end, and reflect it downwards and outwards.
Mr Excitement. lol cool
NICE! 
:+1: