Talk about future projects and donation topic

I’m no driver designer, but I don’t see how one Fet driver, the Q8, would function differently than another fet driver, blf A6. At full power it’s basically direct drive.

You do have less voltage sag with 4 18650 compared to a single 18650, but I don’t think it would make a huge difference.

I think the internal resistance of the led is what controls the current (in direct drive). When you run 2 emitters in parallel, or 3 or 4, etc… your just reducing the resistance which allows for more current to flow.

So an xpl might see 5-6 amps, 4 xpl in parallel might see 20 amps, but only if given enough battery power.

If you look at a quad parallel xpl light with single 18650 you don’t get 20 amps due to battery limitation and voltage sag. I think you get around 12 amps?

I’m sure there are many people here that can tell you exactly what would happen Miller.

Well, you also have the fact that the Q8 holds 4x cells, so more potential current flow. The LED will not regulate current. If there is over-current, the LED will blow.

It will, to some extent, depending on the Vf curves. Some LEDs (eg. XP-L) you can pretty much connect straight to a 4.2V power source. Others (eg. 219C) would likely blow indeed if there is not enough resistance elsewhere in the light. So it’s not unthinkable that the same driver could drive a single LED but it’s not a given either. As they say, the devil is in the details.

Yes this is my thinking
But probably better to gofor a new driver with more regulation anyways (and with single LED and driver with big pcb ample space for chips to do so.)
Thanks

While we are throwing ideas…

One thing i’ve been thinking about is a legoable set of components that would allow for a great number of lights - the generalized idea of the Q8/ST compatibility.

A lot many lights are made of 3 parts: head, battery tube and tail cap. The head itself can be split in 3 parts: optics, led and driver. Imagine all those can be easily swapped. It’s just a matter of using the same ‘interface’ - threads and electrical connections.

If a set of interfaces is agreed upon and published, you can then focus on one part or the other to create new components and implicitly a new set of lights. For instance, instead of building a new light from scratch, you just need to create a new head, or maybe just a new driver. One could build some fancy tailcaps, or a usb charger ‘stage’ that would screw in between the battery tube and the driver, other optics, other firmware based drivers… or a purely decorative ring that could fit in different places… Different materials, different finishes, different functionalities… all legoables.

Of course there would need different interface ‘scales’ to fit the different batteries - AAA, AA, 18xxx, 20xxx, 26xxx… 3x18xxx, 4x18xxx… But still some ‘adapter’ ring could allow to mix them… sometime. Battery carriers could be designed to fit smaller batteries in larger tubes…

Not sure this is a good idea or an unwanted constraint, but it seems a good idea to keep things compatible as much as possible to save on future project design and production.

PS: are the GT and Q8 parts compatible?

That seems very smart
Hard, but smart
Look at the A6 and its Astrolux counterpart, they dont even Lego.
But indeed a default threading size would be the way to go.

Let me just add one little thing off topic.

In my opinion, a good logo is needed for BLF-projects.


What do you think?

Good idea! That would probably mandate a dedicated thread…

A quick sketch:

I totally agree that there should be standards. But at the same time I think they should not be binding, f.e. when a project targets size over all, standard compliance would not be welcome.
And, obviously, we should have different standards for the same part, depending on use. There’s place for lights that have threading smaller than Q8.

The question is: what can be standardized?

  • battery tubes, battery-tube o-rings
  • battery carriers
  • lenses, bezels, o-rings (Q8-based thrower could be compatible with Q8 f.e.)
  • switches
  • drivers
  • LED PCBs

Something else?

I would also consider standardizing a set of battery formats. I count eleven fairly popular battery sizes used in lights. And several others less popular. Cutting that to just a few would reduce the cost of entry for those of us who don’t have huge battery collections yet.

As to drivers, I’ll start with saying that I don’t believe that 17 mm is a good standard for 18xxx batteries, for all regular lights 20 mm will fit. Also, max driver height could be standardized.

Single 18650 width tube, threading like Convoy S series
Single 26650 width tube (also fits 21700/20700) Convoy L series size threading
4*18650 tube, Q8 threading

This seems logical right?
We probably can get the sizes or even CADs from Simon.

Why not just try it and see what happens. Take the Q8 prototype, remove the mcpcb and reflector.
Wire up a single xpl on a 20mm or so mcpcb, find something to hold it down with, maybe a small reflector you have. Hold it down with the Q8 glass. Then install a single weak battery and try it out. Ideally you want to measure the current as you ramp it up. If it survives, then replace the battery for a single high power one and test again. If it survives and the amps are not excessive, try 2 high power cells, etc… Maybe it will hold up to 4 high power cells with only 6 or 7 amps. Maybe not. Testing with an xpl-2 would probably make the amps go up higher. If you think the sst-40 is a good choice, get one of those and try the same test procedure. See what the actual amps are for the stock driver. Then you will know. :slight_smile:

Oh if only days had more then 24 hours :wink:

This concept was discussed in detail in some older threads and it never really made sense. You would have to convince a flashlight company to make all these individual parts without actually knowing which parts are going to sell well and which ones may not sell at all. It’s not practical for a company to make all these different parts and keep them in stock. The average flashlight buyer does not want to buy parts and put it together himself, that is only an enthusiast type of thing which is going to greatly limit sales. The end result will be a bulky looking and feeling flashlight due to the inefficient packaging you get by Lego’ing a bunch of universal parts.

That was the general impression in those older threads.

About right, though frankly I’d skip on 26650 entirely for now and wait for 21700. It’s likely that 26650 will be obsolete before we make the first light with it.

Also, it would be good to specify battery compatibility even tighter:

  • min/max length (i.e. protection)
  • max diameter (protection too, but oversized batteries happen too (Shockli 26650))
  • button top?

Q8 forces many people to buy new batteries, making it ~$57 light for them. I don’t know the reasons behind that, I assume it was a well thought-up decision, but should we require all 18650 batteries to be button top for compatibility with BLF lights? Maybe we should, because we already went that way. Maybe we should re-think and go either way. Or maybe some projects will be better with button-top-only and others with either-way-fits.
Overall, it would be good if we could make sure that users don’t have to buy new cells to use a new light unless that light has way different size than anything they own already.

It’s different when we are designing the lights. Keeping standards (but not procrastinating to keep compatibility) will make the flashlights every bit as good for regular users, while making them better for us. And it also reduces design time.

The SRK design has always mandated button top cells. And to get the most output from the Q8 you’d want unprotected high drain… but that’s just an option. Nothing different from a ‘regular’ SRK clone there.

I would love to see a nice brass AA with a high CRI emmitter too.

Would this end up being like Supbeam K40M in a smaller package? I love the super-wide beam that throws pretty well of that light. It is one of my favorite “general use” lights for sure. If BLF could build a similar wide beam/nice throw light in a smaller package I would buy two for sure.

Yeah a zoomie would be cool to do for sure.
Idk how the XHP35HI fares under a lens.

Too bad there are no round DIE LEDs.

Luminus makes some round ones, but they are neither cheap nor efficient.
There are also COBs.