My novice thoughts are that using 4x XHP50s is about as much light as you can get out of the Q8 practically. I got my first XHP50.2 light and it does about 2000~ lumens from 6-8amps and isn’t busting a sweat in terms of heat during extended running. In the long-term I do not see my Q8 being stock forever(not that anything is wrong with it), but I am on a unending quest for more lumens. Though 20A per cell in a 4x 18650 light doesn’t sound unappealing… I’m not ready to put that many watts in my hand just yet.
Yeah, the main mod I’d like to figure out is a way of handling the heat.
Not that I want the flashlight to end up looking like the International Space Station, which has its huge heat radiator panels (almost as big as its solar photovoltaic panels, but aimed differently)
Just got in some new batteries, thought I'd test them in the modded Q8 from round 3, and show some base Q8 stock measurements vs some relatively simple mods as noted:
The tail PCB was modded to build in a high amp loop for measuring with a clamp meter, plus bypasses added. The blue wires are teflon coated, i think 20 AWG:
This is the stock 18 AWG wires cut back, the soldered up to 16 AWG for the longer run to reduce resistance:
With 4 XPL2's in an early Q8 prototype, I measured 26A using the same wire loop setup, and output was higher even with V5 bin XPL2's.
Mica can take it - I do my soldering on that surface - not a mark. It's actually an old secretaries desk I bought at a going-out-of-biz auction back in the 80's.
Looks like maybe a quad of triple or quad tir optics. Really nice heatsink mount there. In theory I suppose you could get 12K out of it, maybe better. Other option for high output is 4X XHP50's, but that requires the 2S conversion of course, but TA and Lexel have the OSHPark boards for it already.
Stock driver retaining screw, pulled. Threads look good to me:
Bit of stripping in the head:
I used these as a replacement. They seem about dead even with the brass ring. I drilled out the holes in the driver a little bit so the screws do not have to be threaded through the PCB - they clear easy now:
The tray on top of the pic is an assortment from BangGood here. The M3x5 is what I used. The 2.5mm x6 mm are the ones I used to replace the tail PCB flatheads:
I'd rather use panheads on the tail PCB - have some on order.
And by how far do the screws clear the batteries? There are flat tops that protrute a bit so can be used in the Q8, also they should be cleared I think, not just the button tops.
Sure the flat tops will have more clearance, but pan heads or round heads induce no stress on the board, better electrical contact. Also you will see when you get one, those flatheads require the tolerances on the holes to be perfect, otherwise the screws won't set down well. ThorFire did the right thing in having no anodizing on the surface in the tube for the tail PCB contact, but the PCB board contact pads seem lower than the surrounding solder mask, so not sure those pads are even making contact. Soldering them would help but may be hard to get a consistent thickness.
It's hard to tell for sure what's going on but I was getting lower input on Q8 2 of 3, so I used #2's battery tube on #1's head, I could reproduce the low output. With the new 2.5x6 screws and NO-OX-ID treatment on the screw, it appears like I got rid of all the loss's. can I be certain of that? No way - too many dynamics, variables, uncertainties. I'm still not sure, but tightening the tube harder gets better output sometimes. The tube edge to driver grnd ring contact are barely touching on the outer edge of the grnd ring.
It would definately help to cut the threads again in the tail to remove anodisation
+1 for flat screws, but I would file the top of em rather than drilling in the board
ETEX found a sideways clearance from the countersunk screw heads of 0.6 mm using the smaller button-top cells.
Many of us will have bought the 30Q cells from Banggood for this torch, which have the wide “button top”, with 2mm more diameter, i.e. 1mm less clearance.
This is why I am worried about anyone who would put in an ordinary M3 panhead screw which will be proud of the brass ring. This combination, standard pan head screw, cell with wide “button”-top, looks like the cell would have have negative clearance (overlap by 0.4mm), if (two) cells lined up with the screws, which would be down to chance.
Tom E’s domed button top screws will have slightly more sideways clearance, but they do also look from the photo to be almost flush with the brass ring ?
As I said on the other thread, anyone who listened to the people who said ordinary pan-head is OK are, I think, in danger of introducing a potentially serious problem for themselves.
I could only recommend for most people staying with countersunk screws for now, which look to be safe, but ugly.
Only special thin pan-head screws would be suitable, which are not easily sourced for most people.
Are you saying that the battery tube is actually making contact with the screw heads, rather than the ground ring on the driver PCB ?
Because, if so, that seems rather poor to me.
As for the need for good electrical contact with the metal of the head itself (i.e. through the screw threads), I don’t know whether that is necessary at-all. The metal of the head could be completely electrically isolated and the torch should still work I think ? The current path is surely only in through the driver ground ring and out through the brass positive ring ?
I agree to disagree there. Flathead screws are simply the wrong screw to use for this kind of mount. The only reason this is an issue now in production is that ThorFire went from a M2.5 to a M3, and the M3 panhead had a higher head, so, in their infinite wisdom they went with a beveled flathead that requires perfect tolerances, and if they are not perfect, what happens? The screw damages the aluminum threadings in the body, also the screw doesn't sit down all the way, puts stress on the board and screw top. Under a good shock or series of shocks, what happens with components under stress? Things can break or crack.
You will see when you get a Q8 - the M3 flatheads are so tight in the hole through the driver, they thread the PCB. When you take them out, you better use a really good fitting phillips screw driver too. I've been stripping out screw heads - PITA totally...