BLF Q8 color and output measurements

This is not a review, just quick measurements from one sample. Second one is still on the way.

Output on max
Samsung 25R button top
0 sec: 5177 lm
30 sec: 4897 lm
60 sec: 4767 lm

Intensity at 30 sec: 49850 cd

edit: new lumen numbers after cleaning and tightening contacts

Very happy with the bright hotspot. This throws better than I expected even though the numbers do match the specs. The hotspot just is a bit smaller than I thought it would be.

CRI data from the hotspot on max output

Tint shift with different output levels. Just ramped a bit and measured.

Tint shift throughout the beam. Max output once again.

All in all I’m relatively impressed with the tint. The shift is not as big as I expected for a reflectored Cree XP-L light. The corona is quite visibly greener and the spill cooler, but the hotspot stays very neutral on higher outputs. Turns quite green on moonlight and the shift towards green on the corona makes it look ever worse. This is of course with white wall hunting.

Thanks to the Q8 team, you did a wonderful job!

Wow thanks!
Could you check for sandblast powder in the screw holes of the tail PCB?
If there is, clean and try another lumens reading?

:open_mouth: :open_mouth: :open_mouth:

DavidEF, Sorry I don’t speak emoji :wink:
Is this yawn, hmm could make a difference if there is some powder remaining.
Is this shock, hmm a simple blow to bump output seems no reason for shock.
Is this sadly exhalation, no worries IF there is powder it is none conductive, hence getting it out improves output.

It’s the “shocked” emoji. I know there’s no “worries” but it IS a bit shocking that blowing out sandblasting media is a thing to increase output. I’m not saying it’s even a bad thing. It’s just something I’ve never heard of before, and never would have thought about in a flashlight world.

PS: Even with all the negative press about the (IMHO minor) issues with some of the Q8 lights, I’ve still got nothing but good feelings about the project in general, and the light itself specifically. I’m looking forward to holding mine in my hand(s). :wink:

Thorfire will clean out the next 2000 yes, and most are clean, butnthere is a small chance it is there so when I read output below 5K lumens it reminds me of Tom who did a simple cleanup and got one back on par :wink:
It is conveyed and taken care of :wink:

I’m confused lol. Will cleaning the screws out actually help? The two screws near where the positive contact ring for the batteries is?

depends, the 4 screw holes at the TAIL CAP can benefit from cleaning in SOME cases :slight_smile:
The driver holding screws (at the + side of the cells have nothing to do with it :slight_smile:

Just wanted to update you. Unscrewed my PCB. One of the four contact pads on the battery tube had what looked to be thermal compound(or sandblast powder) adhered quite well to it. I had to scrape it off. Was easier when wet so it may have been sandblast powder. Was covering a good portion of the contact area, but my batteries were all at 4.05v so they seemed to have discharged evenly. Screws all had to be cleaned as well. Threads were dirty too but I wasn’t sure how to clean them. I tried rotating a piece of foam earplug material in them. Seems like it may be slightly brighter now but I can’t say for sure because I have no measurement equipment.

Love your work maukka. Thanks for taking the time to post it up. :beer:

No sandblast, but the screws weren’t tightened very well and there was some solder blobs on one of the pads contacting the body. Remeasured after fixing that and cleaning all the contacts with IPA.

Solder blobbed some VTC6’s and surprisingly they also performed worse than my 25R’s. Did the measurements two times to verify. This seems to indicate some sort of battery contact resistance problem, since naturally the VTC6 should perform better.

Pretty much no difference with the 25Rs (2% increase), but the 30Qs did a bit better this time with 4% improvement.

Also remember that my numbers are about 5-15% lower than most people’s and I would definitely consider this falling within specs.

Thanks for the update, strange indeed

Also checked the IR of the batteries at 5A, almost fully charged.

25R 23mohm
30Q 50mohm
VTC6 35mohm

So makes sense.

Why did a think the Q8 was a 6000 lumen light? Must have misread

BLF Q8 4x XP-L 5000LM Professional Multiple Operation Procedure Super Bright LED Flashlight

Yep…my bad

With good cells and clean tail screw holes it is higher.

I do not recommend it (I already know a case of putting one battery in reversed and the springs nicely acting as a fuse :wink: ) , but bypassing the tailsprings will give at least a 500 lumen bump.

I received my Q8s today

I can definately say, that in the tube screw holes its not residue from sand blasting

it is white glue securing the screws
even worse on my sample this glue was not even in the holes it was on 2 screw mounts also on the surface between the PCB and body

furthermore there was some black dirt on the drivers brass ring which I cleaned off with steel whool

On mine the tail screw holes were perfectly clean, no glue.

This was the only thing I found to be amiss: