Q8 modding

That’s not entirely true. A good part of the inefficiency is caused by the increased temperature, which you won’t get at a lower output level. I doubt you can directly use one of the constant current test curves to figure out efficiency once PWM is applied.

When I saw steel_1024 ’s photo in post #121 it did look to me like like a bog standard 45 degree (90 included) head. That is to say I just assumed it was.

Of course, as you said, modifying the PCB to fit the screw is not really the correct approach (i.e., a bodge), even if sure of the match. Another reason to wait, until the way forward is clearer. Meanwhile leaving things as-is is safe, and for many, good enough.

We can be a fussy bunch, and maybe missing the bigger picture, which seems to me to be that this Q8 is turning out to be pretty good. If the worst problem that emerges is a few dicky switch LED boards, I will be very happy.

Here is a link to that photo:

Indeed, it was a “handwaving” argument, and there are a lot of other interactions possibly going on, LED junction temperature being just one. But I think the gist is reasonably correct. i.e. hammering an LED with unconstrained, essentially direct-drive, PWM may not be the best recipe for efficiency. I think.

Mine arrived today.
After seeing the glue on the screws of the base MCPCB and the anodize in the threads. I chased the holes with a tap, cleaned out the threads of screws and reassembled it. No measurements before or after and unsure if the difference is that the sun has gone down… but wow, certainly looks like the living room is way brighter from a ceiling bounce. Wall shot also hurts the eyes more and seems to get warmer faster.

Now for the driver board screws.
Thought all was OK initially but found one was loose. They were lower than the brass ring so I used the light without question.
Drilled out the holes in the driver with a 1/8th inch bit so screws pass without threading the driver board. That was just enough to get the screw slightly lower too. But they are now tighter too. Chased the screw holes in the head. No worries on the screws now. Kept the stock screws.

That's the beginning. Is it your wish to possess this kind of power?

Of course we want more amps! Who cares about efficiency for the first 30 seconds. Dang, I don't mod for efficiency, some may do, but I'd much rather have a 6K-12K lumens max, with a great efficient 150-300 lumens, and it's sooo easy to get with a FET+1 driver, triple drivers extend that efficiency up a bit. Every level, every mode doesn't have to be super efficient - I don't care, as long as I can get max amps.

Look at that guy - that's what happens to you when you are exposed to 10K+ lumens for extended periods of time.

Back to the Q8, I've been seeing a full 1K lumens bump with a tweaked up tail PCB - 20 AWG bypassed springs, bypasses on the traces, contact surface treatments. so 5,500 to 6,500 is realistic to see.

Sorry, haven't had time to post all my test results, but for those that want total max capacity with decent performance, the Samsung 35E cell is looking really good so far. The new 30Q BT's from BG are also doing very well. Helps they are new of course.

Wait - what exactly is the base MCPCB? Do you mean the tail assembly PCB that the springs are mounted on?

This is not the original screw.
I bought from the local store.
Only this M3 (flat head).

Yup, yup. :smiley:
Yeah tail assy PCB.
Haven’t got to the springs or traces yet. Already thinkit improved.

I got 1 more in today, so I got 4 now - I'm frustrated cause I don't have the time I want to spend on them, but the tail PCB is a source of lots of lost amps. Just hard to see or say exactly what it is. I seem to get a small bump just from Nyogel on the main threads, and I've seen this before.

The screws mounting the tailboard to the tube are the - path, right? That’s the case in srk bodies I have with tubes anodized on the end faces where the tailboard makes contact. If the Q8 is the same, the conductivity of the screw material and actual surface contact % between the screw and tube threads would affect current flow and introduce an unpredictable voltage drop.

inside the tube where the tailboard touches the tube is bare, no anodize. The screw pressure assures contact between the tube and board surface.
Part of the problem with the glue on the screw threads is it pushed out on mine between the surfaces reducing the contact.

I cleaned the threads out and screw threads, cleaned the surfaces too. While not measured, I believe it helped some.

Anyone notice the raised brass ring is slightly cupped. I can see why the solder blob cells do well in this light.
I am using HG2 flat tops and they work fine with the slightly raised top, but the contact patch is smaller than a soldered 30Q would be. Think I’m gonna solder a set of 30Q’s for it next.

I kept the dual springs and used bare 22AWG to bypass into the through holes. Did not remove spring to do it. Also sanded off the red from traces on the backside added some solder on top of the traces, prolly not needed as the dual sided traces are best I have seen in width and well thought out tracks.


I care about efficiency in the highest modes.
Because it allows you tu run the max for longer. Your light can absorb only so many Watt-seconds before it gets too hot. I want it to push out as many lumen-seconds before this happens.
This does not mean that I don’t want top amps. But rather that I want the most capable LEDs out there, which bring fair efficiency even when driven hard. :wink:

I'm surprised to hear there was glue there. Maybe I missed it on mine or wasn't there - was it clear in color? Might explain to me why one of my light's battery tube did worse than the others.

Something was there on all 4 screws. May have been clear originally. Pretty certain it wasn’t Loctite (didn’t turn to white powder and wasn’t real hard) so I just called it glue. M2.5 tap cleaned the glue and anodize up.
2 M3 screws on the driver were clean, dry, not glued.

Hello as i write before i recieved today my q8, but unfurtunatelly have the led button problem.

Im trying to help with some photos. My idea was open the button holder ,show some photos, and later fix the led when fix is oficially anounced.

Of course im not modder,or something similar a i have 0 knowleges about this things but i want my q8 full as expected.
To do that i need to remove the button holder i dont know how to do this. Im trying with some tools but, im only doing scratches etc

What tool do you use to do this? Can you do a little how to with 1 or 2 photos please?

Thanks in advance, sorry for me english hope you understand.

If I have time, I'll try to take photos tonight. I used a pair of needlenose with rounded backsides (near the tips, not the pinched surface but outer surface). Using these, insert in a pair of notches in the switch retaining ring (there are 3 1/2 circle notches in the ring), gently apply CCW pressure, while keeping outward pressure on the ring.

What should help preventing scratches is adding some masking tape on the tips of the needlenose.

I've often wondered if a proper tool existed for doing this. Ideally it should be a hard plastic of some sort, rounded outer edge to fit the 1/2 circle notches. I'm sure I could make one out of plexiglas, or something equal, but would probably take me hours.

A machinist could probably make a jig for this in minutes.

Thanks! I will try tonight that tonight, i think with the info you give me gonna be more easy!!

Very apreciated

Just rebuilt the side SW pad. Used lower brightness White 0805 LEDs and a 223 or 22Kohm resistor also 0805 size.
LEDs were more white before install, guess its the silicone button made them look like Cold white, bluish.
Top 2 pics are brighter lighting than the bottom 2 to give an idea what it is. Perfect IMO, enough to find the light SW indoors or darker, and not be annoyingly bright on the night stand.




Did you ask Miller to ask ThorFire what tool to use?

There’s a tool for removing bezels from watches, widely available.
A handle with 2 pins, one in an adjustment slot for separation.