Bypassing the springs is not what we want for two reasons:
Hmm, why not just use “real” button tops?
If someone wants to use solder blobs, they probably can bypass the springs too (and probably don’t care that much about security anyway).
I have no official (unprotected) button top batteries, but they are not that much longer, I fear that over time the same problem occurs.
Hmm and if 1 o 2 springs go weak it could be that 1 or 2 cels are not making proper contact, uneven discharge, shorter runtimes. Yes this needs attention
Would a thicker spring over the small secondary spring fix it?
Has, anyone checked the usable battery length range? I don’t recall it being mentioned. Was this left up to Thorfire?
We need someone to use a ruler and measure how much the springs can move. From light pressure to fully compressed. Then measure the height to the top ring. This should give is a usable battery legnth range.
It should be something like 65mm to 70mm. If the springs are going to loose some of their height over time then we may go from a 65mm minimum height to 66mm. Or something like that.
Anyway, someone should measure this and make sure it’s right.
You can also make a tall solder blob, at least that’s what i have done on some 18650 that came from a HID flashlight battery.
My blobs there seem as tall as the buttons on the single set of button tops i have.
I know its breaking with soldering 101 class rule, but so far it have been working fine in my P 36, though i have now modded its battery carrier with solder blobs so it can also take flat top batteries now.
Where i look from it seem like the mist abundant batteries are unprotected flat tops ( 18650 and 26659 )
Making me wonder why so many flashlights seem to be build for button top batteries.
Couldn’t flashlight makers provide a flat top to button top converter / adapter, sort of like some lights come with a 18650 > 26650 adapter.
For something like the Q8 here just some ring you can but in the battery compartment that will space out the batteries in the top end and so add a button.
I am thinking like a plastic ring with cobber balls in the right places to act as button/spacer.
Here are some possibilities I can think of. Some of this has already been mentioned. But here we go. First, the springs may be too short and/or too physically weak. Enlarging the springs or changing the material to something stiffer may fix the issue. Second, the tube may be too long for shorter cells. Yes, it should be long enough to ensure that longer/protected cells will fit. But, it shouldn’t be so long that only the longest cells will make good contact with the driver board. It might be desirable to both shorten the tube AND lengthen the springs (or make them stiffer). It would be okay if the springs had to be compressed all the way to fit longer cells so that shorter cells can also fit with a little bit of spring compression.
Ideally, the lengths would be such that the compression distance of the shorter spring is the same as the length difference between the shortest and longest cells. So, for a short cell, the longer outside spring compresses until the cell just contacts the shorter, fatter interior spring. But, for longer cells, both the springs would compress all the way down for the cell to fit in the light. Maybe make an extra millimeter or two of initial spring length, so that the permanent compression over time is taken into account.
And it could get worse than runtime if you’re just on the edge so that tipping the light forward makes contact again because the weight of the cell is no longer on the spring. Then you would have one cell charging the others at fairly high current.
It seems that the double springs might be useless here. If they only make contact with protected cells which won’t give max current anyway, I don’t see much point. Might as well just use a single spring of heavier gauge or better material. Either that or stop pretending that the light can run on fewer than 4 cells.
And I agree someone needs to measure how long a cell it currently accepts. It could be that the tube is simply too long be a few mm.
oh wait, wrong measurents, writing correct now, please discard what was written here
Spring height
uncompressed 9.22mm
compressed max 3.23mm
small spring also toughing at a spring height of 5.41mm (I measured this wrong in previous post)
Depth tube from flat tail PCB is on to driver ring 73.93mm
Cell length possible
64.71 - 71.70mm
Cell length needed for double spring action
68.52 - 71.70mm
I think the 30Q bt cells are ~66mm between -metal and +button
So these don’t engage thesmall springs
I might be measuring wrong or use an unreliable digital caliper, would be nice if somebody can confirm or add measurments.
A few measurements:
The currently shortest spring on my Q8, with a battery sitting on top, still has a travel of 5mm until fully compressed.
The difference between a solder-blobbed 30Q and a protected button-top GA cell (Enerpower) is 3.5mm.
So if we want the protected buttontop to fit (we want that), provided that the battery tube length is just right, with solder-blobbed 30Q’s the spring is compressed by only 1.5mm. This is with the current spring type.
This implies that the small second spring, which starts 3mm under the large one, is not engaged, and that any slight bump against the light will cause the batteries to loose contact for a moment (in Narsil this is usually: light turning off).
Slightly different numbers because I used my worst spring for measurements, but conclusion confirmed.
Solution: larger thicker springs with more travel.
Would a new spring spec necessitate another whole round of samples? Any thoughts?
But wouldn’t thicker springs also mean that they no longer work as makeshift fuses?
The springs are a major component of this light for maximum performance that we all waited for, therefore l am willing to wait some more just to make it worth all the waiting.
And, if the travel is already enough then the right solution is to shorten the tube and let the springs do their job.
That sounds like the proper solution, according to the figures there should be ample space for protected cells anyway.
when baking it the tube literally burned a bit (or well some burn spots can be seen)
Did not like it at first, yet now it is very handy to be able to tell the spots of cells in the tube thus what springs are carrying the power.
I have put two 30Q bt cells in and will run them down, as fast as possible without letting the Q8 get too hot. So on turbo till stepdown, cool down and rinse and repeat.
When done, the other two 30Qs also. Let’s see how the springs react to this.
Baking went different, my experiences with:
type II, place them on flames and within minutes see color change
HA3, place on flames, waiting for a looooong time to see a change to olive drab
Q8 it took ages before the color change started, much longer as on the Konos X5, I was really bummed about it, fearing for olive drab.
But slowly and slowly it changed, I wanted to see how far it would go.
After 20 minutes the colors starting changing good, specially on the tailcap
Then the storm hit and I had other things on my mind, one of the things was that the Q8 parts were wet from leaking.
When I had protected the young olive tree, got the stuff away from the leaking indoor waterfall 
and placed containers to catch the water still dripping like crazy I returned to the stove
Now after about 30 minutes the tailcap was nice grey, the head brownish and the tube a bit coppery.
Did not go further then these colors, let it cool, cleaned the parts and put it back, only to see it working, relief.
For now I leave it, for the point is made, nice colors are possible, but use the oven for it takes a long time and flames just don’t cut it and deliver the heat at too small a point on the big head.
And for those who love the flats to align, my Q8 works with the flats of the tube aligned with the head.
Neat I must say, and it gives a twisty interface for a fraction tighter (the normal max tightening) bumps the output (so it can be sued aligned but loses some output, it is just before the physical lockout point)
Yeah seem like there are plenty of flex in current springs to accommodate any length of 18650 batteries, so it would seem the fix would be to shorten the tube a little.
We would want both springs to be engaged no matter what battery is used .
I’m still unsure about why so many people consider using less than 4 batteries.
What is the point of leaving empty slots?
Regarding the springs, I agree with the idea of making the tube shorter over modifying the springs, specially since springs tend to shorten over time, which could lead to only some of the 4 batteries making contact all the time, which could lead to reverse charging at times.
While talking about batteries and springs, if only 1 battery is used to power the light, that passes a lot of current through the springs for that slot, which will heat it up and degrade it. Those springs are not fit to pass the amount of amps needed to power the Q8 without sharing the load amongst all of them.