Same issue, overseas shipping to Canada will take longer than i have before the trip, and that board is not compatible with the 3535 XP-L or LH351 series chips.
Damn late to the party, everybody has moved on. I’ll just throw in my fifty cents…
Did me a few mods to the Q8, naturally the tail spring bypass. Had tried some braided silver to a center tie point. That didn’t work out as the silver is really conductive and just sucked up the solder making it a solid mess. After some thought and as I wanted a clean look, designed a solid copper coil (spring-like but not really springy) that I fitted within a steel cylindrical spring. Copper diameter .030”, 5 turns, which should be good enough for some 6 amps without too much resistance. I had tested the conductivity (subjectively) of the original spring and the contact point to the battery is a line at best (the end loop of the spring). By soldering a cap there is more contact area. This added feature gave a noticeable increase in the light output.
I had trouble testing the current drawn at the tail end. Conventional method thru DMM has too much loss through the internal shunt. By using a standardized external shunt calibrated to 50 mV @ 50 Amps - tested using a 1500 W resistive load and my trusty AC/DC power supply, and with my own tweak on a 250 µA Moving Coil bi-directional meter. Turbo result: some 17 Amps. Yes, this method is not accurate as a clamp on DC meter (UNI-T UT210E Digital Clamp Multimeter/Ammeter). If I were to be testing often or many, the purchase is unavoidable. Anyways, the results are in the ballpark.
I had made a good electrical path thru the body via the mounting threaded hole (removed anodization at hole bottom + brass 1/4” - 20 screw with dog) and a center tie point on tail PCB. There are losses through the wires (although 12 gauge ~ .090” dia.). Tested light output versus shunt by-pass (by twisting body tube to contact driver PCB) via ceiling bounce. Very comparable (as the eye can see).
Also changed the tail and driver PCB’s screws for #4-40 Beryllium Copper. To align the body tube flat with the switch/logo I added a circular shim between the driver PCB and the head shelf. This is not seen when changing batteries, all very clean look inside as well as out. Used flat head screws to clear the center ring. They should make very little contact with the PCB, it’s not required to conduct to the body. Yet, my setup does give a pathway as I’m reversing the circuit in shunt mode. Can’t figure that one out. An internal short would have direct conductivity and have no switch modes (n channel driver).
Finished light estimated 6500 lumens. From data XP-L V6 (BLF post #39 - djozz) would give 1625 lm driven at 4 1/4 amps per emitter.
Quite happy as is. A picture with Jr. (TK-15)
That is a very thorough tuning job of your Q8, and well documented. :+1: And I like your old-school tools! 
(As a european, I had to look up ‘Canuckistan’, from which I learned a bit more about US vs Canada sentiments)
Many thanks, djozz. After my first posting, ’ I suspect my Q8 doesn’t output all 5000 lumens ’ ImA4Wheelr (post #39) suggested using an external shunt. This got me thinking about my earlier builds of some power supplies. After some temporal jumps, I found some industrial shunts and my archived meters. Tested and tweaked the setup against some 800/1500 lights (tungsten filament - some induction but mostly resistive). Results were encouraging and then worked some secondary issues as electrical pathways.
I made due with what I had at hand, and that resembles more of Edison’s warehouses, post-WWII. ‘Old school’ taken as a very fitting compliment!
i tried to reflash my q8 but something goes wrong, i can’t get it done.
i did not touch the cable inbetween, what am i doing wrong?
Does the light still function?
The erase step isn’t necessary, and I’m not sure what it’ll do if erased as a separate step.
The command I use for flashing is:
avrdude -c usbasp -p t85 -u -U lfuse:w:0xe2:m -U hfuse:w:0xdf:m -U efuse:w:0xff:m -Uflash:w:foo.hex
Did someone put the led4power mcpcb with the Luxeons V??
I’ve just finished my light and I’m only making 7300lm at start with bypassed springs and copper screws, I was hoping to get nearly 9000lm
I’m using samsung 30Q cells
This is still early days due to this MCPCB recently coming out. I expect we will see more of these mods soon. For right now I’ve only seen this post.
Also, it’s hard to measure lumens. How exactly are you measuring?
With a integrating sphere
It was making 6000lm with the xpl after changing the screws for copper ones and spring bypassing, and 5000lm out of the box
Just got my new MCPCB from LED4Power today with Luxeon Vs. I really need to invest in a new soldering iron my cheap Harbor Freight 30W took a few minutes of holding in place to get the leads off and then back on these thick copper MCPCBs.
After finally getting the leads resoldered it was time for the absolute nightmare that was widening the LED centering rings… What I ended up doing was clamping the ring with a small pair of vice grips using just enough force to not deform the plastic, and then twirling, spinning, scraping away the inside of the ring with the knife. I got a little overzealous on one and snapped it, but the reflector still took to it and all is well. I really can’t express how mind numbingly tedious this was I really wish my reamer came in the mail for this.
Next I applied thermal paste to the shelf and I probably ended up using a bit too much as usual. I pressed down carefully and gave it a good side to side twist to make sure it was spread and none shot out the sides so that’s good. I then had to get the reflector onto the LEDs and there was no good way to do this. What I did was put the rings on all the LEDs and carefully drop the reflector onto them and luckily they all made it in!
I made quick work of the stainless washer using a dremel.
In the picture it still wasn’t carved enough so I had to widen the notches up. I really underestimated the thickness of the wires. I got it all set and went to test the screw to see how much shorter it needed to be.(I bought an M4 x 20mm bolt) I remember djozz said to go 16mm + the thickness of your washer object. I cut it to 17mm and went to screw her in, but the screw bottomed out with maybe 2mm to go, twisted the reflector off of the centering rings, what a headache that was. I got it all lined up again and twisted the front bezel as tight as I could so the reflector wouldn’t want to spin. With the bolt cut to about 15mm thread length it tightened right up! I’d recommend maybe 14mm + the washer(object) thickness. Results may vary!
You can see the scuffed centering rings pretty good here:
All back together moment of truth and she flashes twice for power! Based on my shoebox which is not scientific I went from around 6300 lumens at turn on to 7600 at turn on. Nice! I can feel it get warm faster which I think is in part due to my more even application of thermal paste. The throw measures just a hair higher than it was prior.
Beam is much nicer than stock on my grey wall:(Note I have the AR lens in also)
New Q8 Beamshots in backyard
MF01 beamshots for comparison
I absolutely love this tint on the Q8. Really wasn’t a fan of how it looked before it wasn’t very even and went from harsh bluish white to egg yolk. Now it looks great outside on foliage or inside white wall hunting.
Nice build, I will try to make and offer some metal washer+M4 screw as option on my page,so (14mm+washer thickness) screw length is optimal?
Pfjew jtm94, well done! Luckily you did not shear off the led domes during fastening the screw.
About the centering rings: I admire your perseverence with the knife, even with a reamer it was pretty time-consuming.
Perhaps the screw hole in the reflector was cut deeper in my Q8, it is good to know that it varies so that you people can already adjust the screw length before reflowing the leds.
Yeah I definitely wish I checked the length prior. I think 14mm thread length + thickness should give enough threads to clamp while avoiding bottomming out. I have to repeat this process for a friend in a few weeks (he’s away with his light currently) and I can update how that goes.
The varying depth lines up with his Q8 having shallower everything else compared to mine. The same LED and driver screws bottom out in his. Maybe his reflector is ran deeper, that’d be a laugh.
I got the washer from Lowes look for specialty washers. Body panel washers is another solid place to look. The djozz method of drilling through a small bar is probably easiest if you have the means.
As for the centering rings… :weary: I was debating trying really dumb stuff the whole time, but the rings are so fiddly I’m sure I’d of destroyed them. Patience is key!
Debating now whether or not I should try swapping in the A20DP MosFET for the Luxeon Vs. I believe they could be pushed a bit harder I have no way to measure amps though.
Nope, but i ordered a new driver and flashed it without erasing.
Really like the lightning and candle mode, thanks for al your work on it TK
Hello all, I’ve had a Q8 for a few months now and my pack of SMD LED’s has finally arrived from China. I went to pop the switch board out and for the life of me I can’t get that thing to come out. I got the threaded plug out just fine, even took the driver out to push from behind and I can’t get it to budge. It looks like it may be glued in but that may be solder flux. I’m not sure what the best approach is at this point but I might try to swap the LED’s out with the board in place. Any advice would be appreciated.
Swapping those tiny leds is quite a task already with the board out, I would not like to try that inside that cavity.
My coated lens arrived but I’ll need some help installing it.
I unscrewed both screws and got the board out.
Do I have to unscrew the next pair of screws?
I have no clue what to do and I don’t want to break anything.!