Future project proposal: the A-family

Agro · 2018-06-11T09:00:19.000Z

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

Agro · 2018-06-11T09:00:33.000Z

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

Agro · 2018-06-11T09:00:58.000Z

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

Agro · 2018-06-11T09:01:33.000Z

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

Agro · 2018-06-08T13:42:15.000Z

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.

Agro · 2018-06-08T13:43:02.000Z

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:

BlueSwordM · 2018-06-08T13:36:16.000Z

OK wut.

Enderman · 2018-06-09T06:29:29.000Z

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.

pennzy · 2018-06-09T14:08:04.000Z

[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?

Enderman · 2018-06-09T20:12:59.000Z

pennzy:

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.

pennzy · 2018-06-09T20:29:40.000Z

Enderman:

pennzy:

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?

Agro · 2018-06-09T20:35:48.000Z

Thanks for the input.

Enderman:

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.

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.

Enderman:

Also, even though getting high numbers is cool for marketing, it’s pretty much useless for a regularly used or EDC flashlight.

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

Enderman:

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.

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.

Enderman · 2018-06-09T22:13:39.000Z

Agro:

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

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.

Agro:

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.

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.

Enderman:

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.

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.

Agro · 2018-06-10T10:13:06.000Z

Enderman:

Agro:

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

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.

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

Enderman:

Agro:

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.

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

H30
Acebeam
Yeah, the latter is inconclusive.

Enderman:

Agro:

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

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.

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.

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

Enderman:

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 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.

will34 · 2018-06-11T01:54:00.000Z

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.

nottawhackjob · 2018-06-11T02:22:23.000Z

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:

NiMh 1.2v is STILL the most underrated battery...... LED Flashlights – General Info

IMO NiMh is underrated and underutilized still to this day vs lithium. Toroid-type boost drivers with NiMH if more would be used in even today’s hi-power lights would surprise many. What even a single AA NiMh high quality battery such as an Eneloop can do with a well-designed toroid boost driver matched to the right LED is frankly astonishing. A 14500 or 10440 lithium battery for example is overrated and over-hyped. The bottomline point is that toroid drivers need more development attention to…

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.

Enderman · 2018-06-11T02:21:10.000Z

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

BlueSwordM · 2018-06-11T02:48:45.000Z

And now we know why so many XHP35 lights can’t reach their advertised outputs.

Agro · 2018-06-11T07:40:24.000Z

I’m a huge efficiency geek. Especially in powerful lights - because then efficiency improves not just runtime but also sustained performance.
I’ve been a big fan of buck, boost, buck-boost drivers.
I’ve been a huge fan of XHP35 HI.

It was hard for me to pick a lower efficiency option….but I believe that for A-lights it just just better.
Why?

Linear drivers use fewer components…and smaller ones
- Driving even a single XHP35 to the max requires a large inductor, interfering with optics
- the sheer amount of board space required is large…A1S should be possible, A4S - maybe, but the smaller variant surely not
Cost
- Buck, boost drivers are costly, especially the high powered ones
- XHP35 is costly, especially when you want several
efficiency difference…it’s not so simple
- high power boost drivers are not very efficient, we’ve seen under 90% when boosting a 6V LED (expect less when boosting to 12V)
  - linear can exceed that at high power levels, at the cost of falling out of regulation when battery voltage drops too low
  - at moderate power levels boost would win, at super-low there’s there’s nothing like resistor…possible with linear, not with boost
- high power buck drivers should be more efficient than linear, though they would fall out of regulation even quicker
- XHP35 is more efficient than any other LED with comparable throw and this is more important than any difference in drivers
- Q8WP is throwier than XHP35, so it deserves to be used as well. But it needs a buck driver. That would be more efficient

So it boils down mostly to price and size. But efficiency gains are not superb either.

Enderman · 2018-06-11T08:44:47.000Z

Quad LED MCPCBs are perfect for compact lights, and running an LED at low currents get extremely high efficiency, so a quad light could get like 200lm/W and still put out hundreds of usable lumens.
I wonder what the most efficient driver for running 3v leds is, either linear or some sort of 1S buck driver that takes 4.2V down to ~3v?

Nichia 219Cs aren’t the most efficient LEDs but you can get over 200lm/W at like 2.8v so that the flashlight could have 500lm regulated output literally until the battery runs out.

Nichia 219C 5000k D320 70 CRI Emitter output test by Texas_Ace, higher Vf then 90CRI version but a lot better output Flashlight Modding and DIY Parts

Here is another test and comparison for ya’ll. You can see my 219C D250 90 CRI test here. Those LED’s came from the group buy that I was part of. Today I am testing one of my 5000k D320 70CRI versions that I got from MTN as a comparison. Same setup as all my other tests. As you would expect the higher binned D320 version has a lot more output but interestingly it also has a noticeably higher Vf. This is not a bad thing really as the D260 version Vf is so low it pulls far too much current. I …

Boost drivers are just bad if you care about efficiency, especially if it’s a 12V LED.
For a 6V led it wouldn’t be so bad, as long as you don’t draw much current.