Future project proposal: the A-family

Rationale

Some A-family features are not obvious. Some are not commonly liked. I’d like to explain why I drew certain elements the way I did.
I’d like to reiterate that if BLF decides so, most of this stuff can be changed.

1. Driver + LEDs on a single board

  • smaller!
  • short thermal path from LEDs to MCU
    • though some drivers shorten the path with extra sensors on the MCPCB getting the same effect
  • some driver components need good cooling too, this solves the problems
  • but all components need to be rated for high-temperature work
  • requires costlier MCPCB
  • hard to swap LEDs
  • very hard to swap driver

2. LD-x4 / Texas Commander style driver

  • low height
  • little board space taken
  • fairly low cost
  • OK efficiency
  • PWM-free
  • unmatched regulated power for the price
  • unmatched regulated power for the size
    • this enables making good use of low-Vf LEDs that are hard to utilize otherwise
      • Luminus SST-40, Osram Q8WP, Lumileds Luxeon MZ, Nichia E21A just to name a few
  • unregulated power as high as with any other driver
  • with a single cell like the A family uses, it can support only 3V LEDs

3. Lights with TIR lenses don’t feature protective glass

  • more prone to scratches
    • but anti-reflective coating scratches too
    • anyway, it is replaceable
  • less prone to breaking
  • no tint shift
  • 1-3% higher output
  • 1.5 mm shorter and over 4g lighter
  • does any flashlight come with antistatic and/or hydrophobic coating? This possibility is lost.

4. DQG-style springless tail

  • light length changes with battery length - never longer than needed
  • large battery contact - minimal resistance
  • no spring and related resistance
  • ~2 mm shorter than PCB + spring, several grams lighter too
  • some members expressed worries about battery safety
    • I’ve heard about some problems with DQG lights, none was battery-related
    • TorchLAB ZeroRez is somewhat similar. No complaints that I’m aware of either.
  • battery rattles slightly when physically locked-out

5. 21350+21700 (maybe +21500 too) battery

Let’s start with why 21700.
It’s a new format and some say it’s the future of Li-ion. Personally, I don’t think so, but I’m sure it has a good future.
There are already very good batteries available in this size and some major players haven’t joined yet. Sony is probably the biggest missing.
One interesting 21700 battery is Samsung INR21700-30T. It is the most powerful cell on the market, beating any 18650, 20700, 26650 or 32650 cell out there.
The availability of this cell actually isn’t always great. Pair it with a FET driver in a low-resistance host (like any A-family light) and it will kill pretty much any low-voltage emitter. Often it will kill several low-voltage emitters.
In the future even more powerful cells may appear. May or may not, flashlights should be prepared regardless.
A-lights’ high-power regulated driver should be able to handle that case well.

  • alternative: 26700
    • thicker, heavier, worse for EDC
    • 15-20% higher capacity
    • for max power, can use 21700
    • could be made available with 26350 compatibility
    • actually I think it would be a good choice for the largest A-lights
  • alternative: 26650
    • as thick as 26700, marginally lighter
    • no 21700 support
    • with DQG tail it’s not any shorter than 26700
  • alternative: 18650
    • less comfortable to hold
    • a little less size, weight
      • very little because we can’t reduce head size - it is limited by driver board size
    • much smaller capacity
  • alternative: 20700
    • it’s uncertain whether it has any future
  • alternative: 32650
    • only slightly better capacity than 26650 with worse power handling? Sadly, I don’t consider it a good option

Why 21350? There are no 21350 batteries on the market now……

  • there are 18350 and 20350 batteries now
  • when 1100 mAh is enough, the full 21700 size just adds useless bulk
  • drawbacks?….I see nothing serious here.

So 21350 is just a why-not choice. It makes the lights better for some EDC uses without making them much worse for others.

It might be possible to support 21500 (and 18500) too.

6. USB Type C connector
Previously I used magnetic connector in the drawings. That drew criticism as a costly option. It is costly and I agreed with that, but thought it was worthwhile….despite that I didn’t have any light with magnetic charger at the time.
Now I do….and I love it. It really feels like the top option.
But at the same time this was the only posh option on the otherwise modestly planned A-lights. Does Type C work? It does. And it works well. Not as well as magnetic connector, but well nevertheless.

Magnetic connector:

  • adds a couple of dollars to the light’s price
  • requires proprietary charging cables
    • may either require the maker to add several cables with different connectors or force the buyer to pick one
    • if the user loses their cables, they have a problem
  • is the most comfortable connector option

Frankly, I still have mixed feelings about it. For me it’s worth it. But it’s BLF, so I drew it with the budget option.

7. Stainless steel bezel

  • bezel is the widest part of the light. Stainless steel enables reducing the width here for not-so-marginal difference in size.
  • maybe optional titanium would be possible?…

LED Choices

Quite a few of these lights are available with many LED choices. Enough to be confusing for buyers. I think that selection should be trimmed for production, but I show all options that I like.
Let me mention some of the LEDs and why I propose to use them.

1. Samsung LH351D (stock and dedomed)

  • fairly cheap
    • and mass-shaving doesn’t cost much
  • single chip (good beam shape)
  • non-flipped chip (no tint shift, good throw when flattened)
  • the most efficient non-flipped single chip that we know
    • though Cree XHP35 deserves a mention as optically it works as if it was a single chip. And at high power levels it’s more efficient than LH351D.
    • Luminus SST-40 deserves a mention too - at high currents it’s even more efficient than LH351D
  • nice tints
  • available in wide range of colour temps and CRIs
  • moderately high Vf
    • lower peak output, especially with weak battery
    • high Vf is good for efficiency with linear driver
      • better sustained performance
    • falls out of regulation quickly
      • but thermals make it drop output quickly too
    • in multi-emitter lights, Vf is actually low
  • fairly small footprint for the performance
  • large die make this LED floody, even after shave

2. Osram Q8WP

  • inefficient, but the best thrower LED that we know
  • expensive
  • only available as low-CRI cool white
  • Osram already has a replacement for it, CSLPM1.TG
    • untested so far
    • The only reason why I use Q8WP in the drawings is that the CSLPM1.TG is untested. If any of those lights is to be produced, I expect it to be produced with CSLPM1.TG actually.
    • Has the smaller brother with the same footprint: KW CSLNM1.TG. It would be better for users who need high sustained throw and are willing to sacrifice lumens for it

3. Cree XP-L HI

  • drop-in replacement for dedomed Samsung LH351D
    • more expensive
    • better throw, worse efficiency
  • good selection of tints, though the high-CRI ones are not commonly loved

4. Luminus SST-40

  • Not a drop-in replacement for dedomed Samsung LH351D, requires its own boards
  • dedomed, makes a good LED for high-output throwers
    • strictly better than XP-L HI
  • only CRI70 cool white

5. Nichia E21A

  • requires its own boards
  • used as a quad is more efficient than any other 3V LED in 5x5 mm footprint
    • not great when you use just one though
    • similar quad (or even 9-up) could be constructed from Cree XD16. It would offer higher output, but much lower efficiency
  • great tints
  • up to CRI 9080
  • not cheap
  • very low Vf, needs a regulated driver (not a problem for A-lights)

Common Accessories

I imagine some accessories which can be used with most or all of A-lights. I’d like to present them here.

1. Clicky tail switch:

This switch is not merely a mechanical lockout - UI should support changing modes with the clicky too.
If UI designer finds it beneficial to do a different UI for dual switch - it’s doable too as the driver can detect whether it’s powered with the switch or not.
How?
Technically the switch construction is based on GFS16 - FET for minimal resistance, power indicator, its own li-ion battery.
When turning on, the switch can make a quick pulse of power before actual full-on. This pulse can be detected by the driver (though this feature may somewhat increase the price).

Note: doing e-switch which would work like a clicky would make it like 4 mm shorter. But I guess dual-switch people don’t really want it.

2. Remote switch
OK, no drawing this time. :stuck_out_tongue:
A remote switch based on the clicky could be available as well.

3. Clip
No drawing either.
Many users require clips for EDC and I guess most A-lights should come with them, either stock or optionally.
Though the fins slope prevents sensible clip usage with larger A-lights. Maybe this should be changed by either removing those fins or adjusting the lights to use larger batteries? Or maybe larger lights just don’t need clips?

4. Diffuser
Turns all lights with 35 mm optics to poor-man’s lanterns. With way less cost, size and weight than a dedicated lantern, but worse beam shape too.

A7

A7 is an EDC flooder.
It comes with a 35-36 mm 7-LED TIR lens. This is a common lens size as it fits nicely standard MR16 light bulbs. It shouldn’t be hard to find a good one for a good price. Also, it shouldn’t be a problem to offer this light with clear, pebbled and frosted lens choices.
Such clear lens should be slightly throwier than standard Carclo triples / quads though the choice of Samsung LH351D makes the light very floody.
Dedomed variant should offer some throw.

This is one of the hottest hot-rods among A-lights, producing huge wall of light for several seconds.

LED choices:

  • Samsung LH351D
    • CRI70:
      • With fresh Samsung INR21700-30T it should do 7000 lumens and 14 kcd (drawing 23A from the battery).
      • With fresh Samsung INR21700-48G it should do 5700 lumens and 12 kcd (drawing 18A from the battery)
      • With fresh Aspire 18350 it should do 4800 lumens and 9.8 kcd (drawing 14A from the battery).
    • CRI80:
      • With fresh Samsung INR21700-30T it should do 6400 lumens and 13 kcd (drawing 23A from the battery).
      • With fresh Samsung INR21700-48G it should do 5200 lumens and 11 kcd (drawing 18A from the battery)
      • With fresh Aspire 18350 it should do 4400 lumens and 9 kcd (drawing 14A from the battery).
    • CRI90:
      • With fresh Samsung INR21700-30T it should do 5800 lumens and 12 kcd (drawing 23A from the battery).
      • With fresh Samsung INR21700-48G it should do 4700 lumens and 10 kcd (drawing 18A from the battery)
      • With fresh Aspire 18350 it should do 4000 lumens and 8.2 kcd (drawing 14A from the battery).
  • dedomed Samsung LH351D
    • CRI70:
      • With fresh Samsung INR21700-30T it should do 5800 lumens and 23 kcd (drawing 23A from the battery)
      • With fresh Samsung INR21700-48G it should do 4700 lumens and 19 kcd (drawing 18A from the battery)
      • With fresh Aspire 18350 it should do 3900 lumens and 16 kcd (drawing 14A from the battery).
    • CRI80:
      • With fresh Samsung INR21700-30T it should do 5300 lumens and 21 kcd (drawing 23A from the battery).
      • With fresh Samsung INR21700-48G it should do 4300 lumens and 17 kcd (drawing 18A from the battery)
      • With fresh Aspire 18350 it should do 3600 lumens and 14 kcd (drawing 14A from the battery).
    • CRI90:
      • With fresh Samsung INR21700-30T it should do 4800 lumens and 19 kcd (drawing 23A from the battery).
      • With fresh Samsung INR21700-48G it should do 3900 lumens and 15 kcd (drawing 18A from the battery)
      • With fresh Aspire 18350 it should do 3300 lumens and 13 kcd (drawing 14A from the battery).
  • Cree XP-L HI
    • quite expensive to have 7 of them
    • CRI70:
      • With fresh Samsung INR21700-30T it should do 5500 lumens and 26 kcd (drawing 21A from the battery).
      • With fresh Samsung INR21700-48G it should do 4400 lumens and 21 kcd (drawing 16A from the battery)
      • With fresh Aspire 18350 it should do 3600 lumens and 17 kcd (drawing 12.5A from the battery).
    • CRI80, 90:
      • possible, I didn’t do calculations

On the drawing you can see it together with Emisar D4

A3

A3 is a medium-beam EDC light. It has only 3 emitters, producing much narrower beam than A7.
It comes with a 35-36 mm 3-LED TIR lens. This is a common lens size as it fits nicely standard MR16 light bulbs. It shouldn’t be hard to find a good one for a good price. Also, it shouldn’t be a problem to offer this light both with clear, pebbled and frosted lenses.
Performance calculations above assume clear lens, for a pebbled or frosted these would be somewhat lower.

LED choices:

  • dedomed Samsung LH351D
    • CRI70:
      • With fresh Samsung INR21700-30T it should do 3200 lumens and 34 kcd (drawing 14.5A from the battery).
      • With fresh Samsung INR21700-48G it should do 2900 lumens and 30 kcd (drawing 12A from the battery).
      • With fresh Aspire 18350 it should do 2500 lumens and 26 kcd (drawing 10A from the battery).
    • CRI80:
      • With fresh Samsung INR21700-30T it should do 3000 lumens and 31 kcd (drawing 14.5A from the battery).
      • With fresh Samsung INR21700-48G it should do 2600 lumens and 27 kcd (drawing 12A from the battery).
      • With fresh Aspire 18350 it should do 2300 lumens and 24 kcd (drawing 10A from the battery).
    • CRI90:
      • With fresh Samsung INR21700-30T it should do 2700 lumens and 28 kcd (drawing 14.5A from the battery).
      • With fresh Samsung INR21700-48G it should do 2400 lumens and 25 kcd (drawing 12A from the battery).
      • With fresh Aspire 18350 it should do 2100 lumens and 21 kcd (drawing 10A from the battery).
  • Samsung LH351D
    • CRI70:
      • With fresh Samsung INR21700-30T it should do 3900 lumens and 21 kcd (drawing 14.5A from the battery).
      • With fresh Samsung INR21700-48G it should do 3500 lumens and 19 kcd (drawing 12A from the battery).
      • With fresh Aspire 18350 it should do 3000 lumens and 16 kcd (drawing 10A from the battery).
    • CRI80:
      • With fresh Samsung INR21700-30T it should do 3600 lumens and 19 kcd (drawing 14.5A from the battery).
      • With fresh Samsung INR21700-48G it should do 3200 lumens and 17 kcd (drawing 12A from the battery).
      • With fresh Aspire 18350 it should do 2700 lumens and 15 kcd (drawing 10A from the battery).
    • CRI90:
      • With fresh Samsung INR21700-30T it should do 3200 lumens and 18 kcd (drawing 14.5A from the battery).
      • With fresh Samsung INR21700-48G it should do 2900 lumens and 16 kcd (drawing 12A from the battery).
      • With fresh Aspire 18350 it should do 2500 lumens and 14 kcd (drawing 10A from the battery).
    • my dream EDC
  • Osram Q8WP driven to 21A for higher throw, but much lower efficiency
    • extremely hot-roddy
    • needs the 21A to be regulated because Samsung INR21700-30T will kill the LEDs otherwise. That high regulated output may or may not be possible.
    • 3000 lm, 64 kcd
  • Cree XP-L HI
    • CRI70:
      • With fresh Samsung INR21700-30T it should do 3000 lumens and 38 kcd (drawing 13A from the battery).
      • With fresh Samsung INR21700-48G it should do 2600 lumens and 33 kcd (drawing 10.5A from the battery)
      • With fresh Aspire 18350 it should do 2300 lumens and 29 kcd (drawing 9A from the battery).
    • CRI80, 90:
      • possible, I didn’t do calculations

On the drawing you can see it together with Emisar D1 and Emisar D4

A1

Here comes A1, an EDC thrower slightly larger than Emisar D1.

Reflector has exactly the same dimensions as Phoenix Electroforms PA19.01, so for the big budget users there’s an easy upgrade path.
PA19.01 costs $45 when buying 1 piece or $35 when buying 100. So manufacturer could offer it together with UCL2-class window as a $50 option. Expensive…but I’m sure there would be buyers willing to pay so much for ~15% higher performance.

5 LED choices:

* Osram Q8WP driven to 7A

* 990 lm, 130 kcd with cheap optics

* 1100 lm, 150 kcd with upgraded optics

  • dedomed Samsung LH351D for those wanting higher output (or warm or neutral or high CRI…)
    • With Samsung INR21700-30T or Samsung INR21700-48G (LED driven to 6A):
      • 1200 lm, 73 kcd with cheap optics
      • 1400 lm, 82 kcd with upgraded optics
    • With Aspire 18350 (LED driven to 5.5A):
      • 1200 lm, 75 kcd with cheap optics
      • 1300 lm, 85 kcd with upgraded optics
  • stock Samsung LH351D for those wanting even higher output
    • With Samsung INR21700-30T or Samsung INR21700-48G (LED driven to 6A):
      • 1500 lm, 50 kcd with cheap optics
      • 1600 lm, 57 kcd with upgraded optics
    • With Aspire 18350 (LED driven to 5.5A):
      • 1400 lm, 48 kcd with cheap optics
      • 1500 lm, 54 kcd with upgraded optics
  • Cree XP-L HI
    • With Samsung INR21700-30T (LED driven to 5.75A):
      • 1200 lm, 91 kcd with cheap optics
      • 1300 lm, 100 kcd with upgraded optics
    • With Samsung INR21700-48G (LED driven to 5A):
      • 1100 lm, 85 kcd with cheap optics
      • 1200 lm, 95 kcd with upgraded optics
    • With Aspire 18350 (LED driven to 4.75A):
      • 1100 lm, 82 kcd with cheap optics
      • 1200 lm, 92 kcd with upgraded optics
  • Dedomed Luminus SST-40 driven to 8A
    • 1400 lm, 100 kcd with cheap optics
    • 1500 lm, 110 kcd with upgraded optics

Note: there are no technical reasons not to include CRI80/90 LEDs, I just didn’t bother with performance analysis

A1S

A1S (A1 Supersized) is a compact thrower, a bit larger than C8, about the size of Emisar D1S.

Reflector has exactly the same dimensions as Phoenix Electroforms PA11, cut down to remove the rim from the front. Such compatibility enables upgrade.
Phoenix confirmed to me the possibility of cutting the reflector, but didn’t provide me with pricing information, so I have no idea if it’s feasible for the manufacturer to offer such options. I it’s not feasible, I think it would make sense to increase the reflector size to 50 mm outer diameter.
There are many lenses with 50 mm diameter and so other A*S lights would probably use them. Upsizing A1S like that would be better for family uniformity.

  • Not very hot, some variants should be able to sustain its output until battery runs out.
  • parts sharing: it can use exactly the same driver board as A1
  • offered with the following LEDs:
    • Osram Q8WP driven to 7A
      • 990 lm, 220 kcd with cheap optics
      • 1100 lm, 250 kcd with upgraded optics
    • dedomed Samsung LH351D for those wanting higher output (or warm or neutral or high CRI…)
      • With Samsung INR21700-30T or Samsung INR21700-48G (LED driven to 6A):
        • 1200 lm, 120 kcd with cheap optics
        • 1400 lm, 140 kcd with upgraded optics
      • With Aspire 18350 (LED driven to 5.5A):
        • 1200 lm, 130 kcd with cheap optics
        • 1300 lm, 140 kcd with upgraded optics
    • stock Samsung LH351D for those wanting even higher output
      • With Samsung INR21700-30T or Samsung INR21700-48G (LED driven to 6A):
        • 1500 lm, 84 kcd with cheap optics
        • 1600 lm, 95 kcd with upgraded optics
      • With Aspire 18350 (LED driven to 5.5A):
        • 1400 lm, 80 kcd with cheap optics
        • 1600 lm, 90 kcd with upgraded optics
    • Cree XP-L HI
      • With Samsung INR21700-30T (LED driven to 5.75A):
        • 1200 lm, 150 kcd with cheap optics
        • 1300 lm, 170 kcd with upgraded optics
      • With Samsung INR21700-48G (LED driven to 5A):
        • 1100 lm, 140 kcd with cheap optics
        • 1200 lm, 160 kcd with upgraded optics
      • With Aspire 18350 (LED driven to 4.75A):
        • 1100 lm, 140 kcd with cheap optics
        • 1200 lm, 150 kcd with upgraded optics
    • Dedomed Luminus SST-40 driven to 8A
      • 1400 lm, 170 kcd with cheap optics
      • 1500 lm, 190 kcd with upgraded optics
    • Luminus CFT-90
      • just kidding

On the drawing you can see it together with Convoy C8 and Emisar D1S
Note: there are no technical reasons not to include CRI80/90 LEDs, I just didn’t bother with performance analysis

A4S

A4S is a high-output light with 4 LEDs and a deep reflector. The reflector has the diameter of the A1S-one.

LEDs:

  • Osram Q8WP LED
    • 4400 lm, 200 kcd with Samsung INR21700-30T with 28A drawn from the battery
    • hot-rod overheating in mere seconds
    • needs the 28A to be regulated because Samsung INR21700-30T will overdrive the LEDs, maybe even kill them
      • is it possible for this driver to regulate 28A for several seconds?
  • dedomed Samsung LH351D
    • not brighter than Q8WP, but much more efficient. High sustained performance
    • 4400 lm, 96 kcd with Samsung INR21700-30T with 19A drawn from the battery
    • 3600 lm, 79 kcd with Samsung INR21700-48G with 13A drawn from the battery
    • 3000 lm, 65 kcd with Aspire 18350 with 10A drawn from the battery
  • stock Samsung LH351D
    • the most efficient variat, but sacrifices throw
    • 5300 lm, 61 kcd with Samsung INR21700-30T with 19A drawn from the battery
    • 4400 lm, 50 kcd with Samsung INR21700-48G with 13A drawn from the battery
    • 3600 lm, 41 kcd with Aspire 18350 with 10A drawn from the battery
  • dedomed Luminus SST-40
    • 5200 lm, 130 kcd with Samsung INR21700-30T with 25A drawn from the battery
    • 4300 lm, 110 kcd with Samsung INR21700-48G with 19A drawn from the battery
  • stock Luminus SST-40
    • 6300 lm, 68 kcd with Samsung INR21700-30T with 25A drawn from the battery
    • 5200 lm, 56 kcd with Samsung INR21700-48G with 19A drawn from the battery

On the drawing you can see it together with Sofirn C8F

Note: there are no technical reasons not to include CRI80/90 LH351D, I just didn’t bother with performance analysis

Alternative:
There are many lenses with 50 mm diameter and so other A*S lights would probably use them. Upsizing A4S to get the same head diameter would be better for family uniformity.

Other A-lights?

I can see the A-architecture applied to several more lights.

1. Zoomie
I definitely think it makes sense to make an A-zoomie. Or several. In fact I have some drawings in the works.

2. A7S
Larger hot rod? Why not? I didn’t draw one, but if there’s interest - I may. Quick and dirty: 39A current draw with Q8WP for 6600 lm and 170 kcd. With SST-40 9000 lm at 34A.

3. Headlamp

  • does anyone need a hot-rod headlamp?
    • with different drivers (and 6V LEDs) efficiency can be better leading to longer runtime and higher sustained performance
      • though with higher price and lower peak performance
  • I’m not convinced 21700 is great choice for a headlamp - 18650 is already bulky enough. But I have a hunch that there are people who disagree…
    • the market for 18350 headlamps certainly looks underserved. A-family headlamp could go there.
  • headlamp-powerbank doesn’t seem like a bad idea

4. Lantern

  • does anyone need a hot-rod lantern?
  • 21700 seems like a nice choice for a lantern. Not picked by anyone of the market yet, but that is likely to change soon.
  • a diffuser on top of A3 / A7 would give 70% quality for 5% price and 5% weight (for someone who has A3 or A7 already)
    • A3 and A7 have different head diameters, so diffusers would have to be different

5. Mule
Technically there are no problems. Regardless of how large it should be. Could even re-use all components except for the body.
But is there enough interest?

Finally, family picture:

OK wut.

Personally not really a fan of all those designs.
I only like tube lights.
If I can fit a flashlight with a bigger diameter head in my pocket, then it would make no difference if the whole light was that diameter.
Even a 26650 light can easily be gripped in one hand so the only reason to have a non-tube light is if you need a head bigger than like 40mm.
.
Stuff like USB C charging, long throw / high cri / high efficiency LED options, LED and driver on same board for compactness, are all great ideas.
.
Also, even though getting high numbers is cool for marketing, it’s pretty much useless for a regularly used or EDC flashlight.
Having long battery life, stable output, no drop down or FET or direct drive, is what really matters.
The longest runtime would be using a shockli 26650 5500mAh cell.
The longest runtime while minimizing mass and size is a samsung 18650 35E.
Maybe in the future 21700 cells will get better but currently the highest capacity one is the samsung 48G which is slightly worse in wh/kg and wh/L than the 18650, but it is still very close (a lot closer than the best 26650) so if you need more capacity it’s definitely the best option.
.
I don’t think anything below 18650 is worthwhile even considering, having looked at the wh/kg and wh/L of the best 16340, 18650, and 14500s.

[quote=Enderman]

.
Also, even though getting high numbers is cool for marketing, it’s pretty much useless for a regularly used or EDC flashlight.
Having long battery life, stable output, no drop down or FET or direct drive, is what really matters.

What do you consider a regulated output level in a 18650 tube light that is sustainable to be? I know it is variable to the need but just wondering what a moderate level is approximately. 5-600 lumens?

Well it really depends on LED efficiency, if you have multiple LEDs running at a low current each (getting high lm/W) then you should be able to get both high output and long regulated runtime out of an 18650.
I’m not sure if it would be 500, 1000, or more lumens, that would require some calculations to be done.

Driver types confuse me . Would a Sofirn C8F be considered well regulated at lower levels?

Thanks for the input.

If BLFers in general would like A-lights with 26650, that could be changed easily.
Personally I EDC lights in a backpack, so for me weight and overall volume are more important than any individual dimension. Larger head doesn’t add much to volume, but can nicely improve performance.
BTW I may draw a near-tube A-light later, still with 21700. I’m not sure, that may be applicable to more lights, but not having actual driver design I was pretty conservative with sizing. But aspheric zoomie should be doable.

Removing powerbank would help as well. That may be a good light, but not an A-light.

It may be useless for you, but is not in general.
I love my D4 and use its Turbo a lot.

On low currents, LG H30 or Acebeam “5100 mAh” (which uses a cell I failed to identify) are the highest capacity 21700. For moderate currents that may be either 48G or Acebeam.

There are uses where Wh/l and Wh/g are meaningless. That is - when you have enough energy. Beyond that every size increase is a waste, regardless of how it improves power density. Personally I love 18350 - runtime is good enough for my EDC, the best cell has good IR and it’s significantly smaller and lighter than 18650. Even DQG Tiny 18650.

Powerbank function may be an excuse for some to go up with the cell size from what they use now.
For others - recharging that comes with it may be a good reason to go down.

I’m a huge efficiency geek. But sometimes less efficient solutions are simply better.

I’m sure if they removed turbo mode and made ‘high’ the new turbo you wouldn’t notice a difference.
The difference between high and turbo is not very noticeable after the first few seconds.

Do you have any reliable tests for those cells? Hopefully you’re not going off of the numbers that the manufacturer claims.

[quote=Agro]

It may be useless for you, but is not in general.
I love my D4 and use its Turbo a lot.

That’s true, but for most people you don’t choose a runtime and then pick a light which is the smallest size.
You do the opposite, pick a size limit that you are willing to EDC, and then find the best battery for that size light.
As far as I can tell, 18650 is a pretty popular EDC size.

Also, it doesn’t make a lot of sense to go with just “enough” runtime when you could increase the size of the light by like 30% more and get 400% more runtime.

I rarely run it for more than a few seconds. And yes, the difference is very noticeable. 3500 lm Tubo, 600 lm stable.

H30
Acebeam
Yeah, the latter is inconclusive.

AAA is also a pretty popular EDC size. Different people-different needs.

I disagree. By “enough” I mean “it never runs out before I can recharge”. 400% of “never ends” is still “never ends”. 130% of something is 130% of something.
I could spend that 1-2% to insure for the case that never happened, but may in the future. But not more than that.

The concept of A4S is great.

I think multi-LED is the future of flashlights, BUT along with a powerful boost driver. The era of DIY FET driven lights being more powerful than productions lights with boost driver is coming to an end. One of my favorite lights is the Sofirn C8F, and the only way to improve it is with a boost driver so it gets flat regulation.

Linear drivers are appealing for some people but for me it is dumb to burn excess power, might as well just drive the LED harder.

Hell you shoulda heard the gruff I got for pushing the need for better boost drivers in this NiMH thread. Inefficient this inefficient that. But whaddya expect when maximizing output from a stinky little AA Eneloop? A perpetual motion machine? :laughing:

I mean they’re inefficient in distinct ways yes but they’re not THAT inefficient considering linear driver excess power waste thru heat.

Anyway, I believe there’s serious progress yet to go on them too.

Boost drivers severely drop in efficiency the more you boost the output voltage above input voltage.
Here’s a graph for example: