Talk about future projects and donation topic

Nitecore makes some compact lanterns, like the LA10 or LR10. In case that would be close enough.

There’s also the option of putting a diffuser cone on a regular AA/AAA/16340 light. Then it could serve as both flashlight and lantern. The Olight S1 Mini Ti works well for this, and IIRC it comes with a GitD cone.

I know, I know. Sometimes I’m acting a bit silly. But I can’t help myself. This light is so ridiculous that I just had to draw it. Or maybe it’s not?
This is expensive light. High budget. But there’s nothing cheaper in its niche.
Well, there’s nothing more expensive in that niche either.
Single 21700, CFT-90, FET+linear driver:

Cheers to kiriba-ru and Lux-RC.

It seems like the driver designers on this forum have pretty much concluded that you need a high-powered buck driver to handle the CFT-90. I think this is why no one is really building a single cell flashlight around that emitter.

I suppose if you could get a driver to work well and then match it up with something like a Samsung 30T you would have a pretty interesting light.

Hi Miller,

I would like to make a donation for all the great work you guys have done, and for all I have learned on this great forum.
I have also bought some of the great BLF developed flashlights, and saved money with coupons etc.
Can I please confirm that this is the correct address to donate to on Paypal:?

wimmm777@gmail.com

The Miller has been pretty busy lately and hasn’t had much time for forum stuff, but I’m sure one of the other members like ToyKeeper or Texas_Ace can confirm things given a little time.

Thanks JasonWW
I will wait for confirmation…

Given the situation with the person who started this thread, would it not be a very good idea to have sb assign this thread to a person active in BLF??

Or, at the very least; remove the donation information as it is now…. (copy & pasted below from post 1.)

wimmm777$gmail.com (replace the $ for @)

This outdated information should not be left active as far as I am concerned.

I’ve considered opening up a Patreon account or something in case people feel like donating to me personally, but I always found it a bit odd having a general BLF-project donation fund. Fair and agreeable distribution is difficult, and I don’t like handling other people’s money.

Anyway, The Miller has been mostly absent since late 2017. I don’t think he is really following current events on BLF or distributing donation funds any more. He has been a bit too busy dealing with illness and flooding and other issues.

While on the subject of donations, what has become of the balance listed in post # 1???

It was last updated on 1 October 2017…… copied & pasted below.
……………

Edited by: The Miller on 10/01/2017 - 03:56

BLF DONATIONS OVERVIEW
Total input 830,52
Total spend 344,15
Funds left 486,37

A proposal without a picture as it’s too unclear to me how exactly I’d like it to be done.
Hotrod keychain light:

  • Turnigy 180 mAh 15C Li-Poly (36x8 mm cylinder)
  • TIR lens, one that is available with both clear and pebbled variants
  • XP sized LED (with Samsung LH351D being the flood choice, maybe one of Osrams for throw?)

Now to things that make me wonder…

Driver:

  • Should it be FET+1?
  • Maybe Texas Commander to enable higher regulated current?
  • Maybe driverless to make it smaller? (bad idea, would quickly turn too hot)
  • QTC? With bypass to direct drive?

Controls:

  • Twisty?
  • E-switch? With Narsil / Andruil?

Built-in charger:

  • No, too large?
  • Yes, MicroUSB?
  • Yes, but just include headers to plug a RC charger?

Some notes on the battery:

  • recharging can be really fast, 12 minutes
    • though for durability I’d limit it to 20-30
  • 10 mAh/mm³
    • 10440 gets 9 mAh/mm³
    • 10180 gets 5 mAh/mm³
    • 18650 gets 20 mAh/mm³
  • 45 mAh/g
    • 10440 gets 32 mAh/g
    • 18650 gets 70 mAh/g
  • 2.7A continuous discharge

Considering that sub-10440 batteries tend to be of low quality, I think this one is really worthwhile.

I still do not see why a simple FET+1 driver would not drive the CFT90.
About the design: you emphasized heavily on the finning (I like that) but still what you have drawn I estimate can dissipate about 25W, not the 100W that you want the CFT90 ideally to run at. But since people do want that 100W (or whatever the 21700 will provide) for a while before the stepdown, you can buy some time with extra aluminium mass near the led, also good for distribution of heat to the fins. So I would suggest a bit less deep fins and a bit more aluminium.

I would love to know how do you estimate the performance of these fins?

Frankly, I think it would be good to make the reflector like 4 mm larger. Right now it’s quite small when considering the total size of the light. It was just easier to draw it like that because it’s just a modification of one unpublished drawing……

Making reflector larger would improve heat shedding. Though certainly not quadruple it. My intention with this light was to have fins remove at least 70% of heat. If that was the case, already quite large chunk of metal behind the LED should allow for a nice Turbo times - and superb sustained performance would be a nice bonus.

Pure guesswork extrapolated from my experience with the S2+ ( How hot does an S2+ get at 2.75A? Comparing an anodised Convoy S2+ with a fluorescent yellow powdercoated Convoy S2+ )
I guessed that the outer surface area of your design would be about three or 4 times that of a S2+ and that an end temperature of 90 degC would be undesirable.

It would be wrong to treat those fins literally. I think if such light was to be done, someone should just design a light with lots of fins in this area, adjusting exact fin spacing and thickness to whatever thermal CAD shows to be best within structural limits.
But I was curious whether your 4x was about right, so I did just that: treated those fins literally and calculated area.

I got 5 times the area. So about right. Though in your S2+ analysis I see the light being run at 10W+, not about 6 like your calculation would show.
It seems to me that this light can shed very very roughly 50W with 90 C body temp (I don’t see ambient temp in your tests…can I assume 20C?). Or very very roughly 25W with more sensible 60C. In the winter, with –10C ambient very very roughly 50W again.

Though it doesn’t include cooling with hands, it adds some.
Minor increase of fin area by making reflector larger can help, but not enough.

One thing you have to watch for with heatsinking fins is that deep, narrow cuts between fins can result in stagnant, hot air at the bottom of each cut that doesn’t circulate because it’s buffered away from the cool air outside by the warm air in between.

This means that you can’t assume heat dissipation will scale purely with the surface area. The arrangement of that surface area in terms of getting as much free air circulation as possible also matters.

There is often an optimal point in width, depth and separation of fins, sitting somewhere on a spectrum of:

  • no fins and poor heat dissipation;
  • through several fins with optimal width, depth and separation for free air circulation and good heat dissipation;
  • to lots of thin, tightly spaced, deeply cut fins with stagnant air zones at the bottom of the cuts and mediocre heat dissipation.

The last option is better than no fins at all, but not as good as the optimal arrangement. In the absence of (expensive and complex) modelling software, it’s not unusual for manufacturers to build several prototypes with different fin arrangements and physically measure which does best.

Good points, thanks.

OK, I hate to not have drawings. I still consider the questions above to be open, but I drew pretty much the smallest variant:
10 mm TIR optics, twisty with QTC pill and bypass to real direct drive (thanks CRX), tiny charging connector.
Pictured next to DQG Tiny AAA.

Adding features will make it larger than Tiny. So will increasing TIR size.
Though Tiny has 15-20 times lower output, so maybe that’s not the best light to compare to…
Is it worthwhile? I don’t know. But I’m partial to QTC twisties. :slight_smile:

I split out the A-lights to their own thread:

I believe that at some point adding more aluminium is just wrong, it adds too much weight.
If you heat 1g of aluminum from 20C to 60C, it can store ~36 Ws of heat.
If you heat 1g of paraffin wax from 20C to 60C, it can store ~310 Ws of heat.
That’s why some time ago I suggested this:
http://budgetlightforum.com/comment/1310922

ADDED:
Paraffin wax is 3 times lighter than aluminium, so volumetric heat capacity is just 3 times better.

I don’t think this is relevant to flashlights.

We don’t want to store heat, we want to transfer it.

For sustained performance, transfer is everything, storage is nothing.
For turbo times both matter. In highly overpowered lights (and this one is highly overpowered even with all those fins), storage is far more important of the two.