Q8, PMS SEND TO THOSE WITH ISSUES BLF soda can light

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.

Boggles my mind too. It just makes sense to me to allow the cells to share the load and stress all components less. While the light will run with fewer cells I view that as being for emergency use only. Want a lighter light or less max’ output? Get another light.

Unlike some of the people above I do think that bigger springs made of of thicker wire is the way to go (it will still act as a fuse alright), now that I took a closer look at the shortest spring it does show signs of collapse: part of the spring is discolored and deformed assymmetrically.

You may simply state that this light is not meant to be used with one cell only, but it should not loose its springs if you happen to try that.

It seems like we are slowly discovering how a 20+ amps flashlight should be build. And thusfar we are doing well at it, but still adjustments need to be made.

Yeah, seems light a good characterization of what is going on here. And now that I see the tail PCB again close up, I think thicker springs would be good whether longer (to fix the tube length issue) or not.

Carry on folks! You’re doing fine!

Who didn’t expect some teething problems? Now is the time to find them.

We hoped to find them all a few prototypes earlier actually, but better late than that all 1500 run into problems.

Oh well, regardless of how it gets fixed, the important thing is that we found the issue, and honestly, it does not seem all that hard to fix. Either thicker springs or shorter tube are both simple modifications, from a manufacturing perspective.

I just realised that the PCB has holes right beneath the springs. Are those there to facilitate spring bypasses? Nice touch.

how about the big tail spring of the S70S?
13.76mm
4.69mm compressed max, no grinding of metal it just becomes a nice dome with spiral looks

An argument could be made that changing the springs messes with the BOM, and if the other springs have already been bought, they’re now wasted (unless they can be used for another product). Shortening the tube is the really easy change from a manufacturing perspective, and saves material as well, which might add up to being able to squeeze more lights out of the same amount of stock.

EDIT: Note to the Q8 Team. Don’t take me any more seriously than you want to. I’m (mostly) just yappin’. Whatever decisions are made, I’m sure will be the right choice.

Shortening the tube does sound like a very practical option assuming they have not locked down the CAD design, but I see no reason they would have at this point.

@The Miller
Please can you add me to the list, hope its not too late to join?

Thanks.

That spring looks about perfect, Miller! With its length and 9mm travel, with the current tube-length it compensates for the shorter batteries while still enabling longer ones. And it handles more current before collapsing.

Am I the only one who thinks that it is easier to change a type of spring (which is available at Thorfire) than to change a battery tube design?

I like the idea of S70 springs. But the small springs need to be longer a little too to make contact both spring with short batteries also.

Welcome to BLF!
Yes will update list later

Djozz I think so too.
We know they have these springs sourced and that they work fine.

But springs are a source of added resistance in the circuit, and longer springs will mean greater losses. If the springs are lengthened, we’ll need another round of Q8 samples to be tested. And, if Thorfire has already sourced the shorter springs, they will be left holding onto stock that they may not be able to use, unless they have other lights that use those springs. Plus they may have to order more of the longer springs in order to make all of our lights if they don’t keep thousands of them lying around. If that happens, it will add more waiting time.

Also, just thought of this, the solder pads for the springs on the tail PCB’s are too small for those bigger springs. They will have to re-design the tail PCB.

Thanks, and thanks for welcome as well but I have been lurking around for a number of years… Just noticed only single digit posts so clearly didn’t say much so far!

Argh and I just notice you are a BLFer much much longer then me, sorry automatic response with 1 or 2 posts members asking to be put on the list :wink:

Yeah David you are right.
Sigh
The S70 springs are nice and thick though
Looking for a solution that requires the least redesign

My two springs where I emptied 2*2 30Q on turbo on have indeed sagged about half a mm

There is a basic problem of accommodating all lengths of cells with a spring on only one side. If we get into longer or stiffer springs, I hope the long protected cells won't suffer. I found some struggle getting the body to thread with protected cells in there now.

Of course mine will get bypasses:

  • no high amps going through the springs (no heat to deform them)
  • don't have to worry about getting good spring compression to reduce resistance
  • I can't see how an upside down battery would make contact to the brass ring, so using the springs as fuses, I just don't see. Even if it was forced (solder blob on the Batt- end?), the traces on the tail PCB make good fuses - I've seen this before in Shocker battery carriers.

If we do want to improve on the springs, two issues:

  • stronger, stiffer steel (tighter fitting short cells, can handle the heat better)
  • increase conductive coating thickness (handles high amps better, probably less heat generated)

I do think (agree to what was said) the inner springs are too short. They should come right up to the top of the outer spring. This would probably help as well.

Just received my VTC6’s from GB. They are dated June 2016 (C6AYF16J), which I think is not an issue.

Now. My. want. da. flashlight.
:slight_smile: