Talk about future projects and donation topic

I’ve been thinking about it for a while…and now I decided this is the way to go for the A family.

Let’s not make them 21700. But rather 21350.
Pros:

  • smaller by 1/3

Cons:

  • there are no 21350 batteries

So…it needs a little explanation.

First, there are no 21350 batteries now. But there are 18350 and 20350 now. And 21350 are likely to arrive eventually.
Why 21350 and not 18350 or 20350 then? Because it enables us to use extension tubes for 21700. And 21500 if they eventually arrive (18500, 20500 is available now).
21700 have 4600 mAh.
18350 and 20350 have 1100 mAh. And higher internal resistance which reduces performance.

Quarter capacity for 1/3 smaller size. Is that a good trade-off?
It depends.
If you don’t need more than 1100 mAh anyway - yes, it is. And seeing how many people EDC lights smaller than 18650 - I believe there are quite a few who don’t. On a twist, capacity reduction turns it from good powerbank to bad powerbank. So for those who EDC powerbanks and tiny lights - they would still prefer 21700.

So the real pros:

  • smaller by 1/3 for those who don’t need more than 1100 mAh
  • (optionally) smaller by 1/5 for those who don’t need more than 2000 mAh
  • just as large for those who do need more energy

Cons:

  • slightly costlier
  • worse thermal transfer to the tail
  • stylistically challenged
  • when using smaller batteries - slight to moderate performance reduction (depending on model)

I added a rough outline of Emisar D1 to the pic.

Is it just me or has this thread seem to have turned more into “agro’s future projects” rather than “BLF future projects” ?

No, it has not.

It has not because I neither have the capabilities to turn these drawings into real lights nor will have them in the future.
So these are just drawings and will remain so unless someone different from Agro will decide to make them.

Seeing how little response they generate I conclude there’s little interest. And find it extremely saddening. Because few times in my adulthood I was as convinced I did something right as with them. And if there’s no interest, they will never be made.

That said, I almost monopolized this thread. Again. The reason is that there are apparently few people willing to discuss the topic.
Is it right? Is it wrong? I don’t know, it is what it is.
I am willing to discuss and I intend to continue. Because even if I’m mostly discussing with myself - I want this to be public.

Agro, time to buy a lathe and start making your own lights! Lol.

Yeah, these seem like very specific and customized lights, not something that can be mass produced easily and make tons of profit from thousands of buyers.
I would recommend modding or scratch building stuff like this yourself.
Sometimes building the stuff yourself gives more satisfaction than simply buying it :wink:

It’s not the time to buy a lathe. 3/4 of the lights which I tried to mod don’t work. Well OK, I broke 1 beyond repair, the others can be fixed, I just wait for tools / parts / motivation.
Anyway, lathe is way off. And I don’t expect I’ll ever be in the position when I’d consider it good.

I’m a bit surprised to read that these are very specific and customized lights.
Because I went out of my way quite a few times to make them more generic.

I did include some controversial stuff in them. This may be what you perceive as “specific and customized”. I pointed it out and presented the rationale. The purpose was to start a discussion. Because my point is not to have them made to my specs but to BLF specs. The discussion didn’t start.

Well first you were talking of a 21700 flashlight, a battery which almost nobody has, and now 21350 which doesn’t even exist.
Why would people buy a 21700 flashlight if they have plenty of 18650s and 26650s already, which are still better (power density) than any 21700 batteries that are available atm.
Stuff like dedomed LEDs, unibodies, magnetic chargers, etc. manufacturers simply won’t do for multiple reasons, the first often being cost.

Unless there is something special about the light, like super low cost, extreme throw, high lumen output, etc. it’s not going to draw in the thousands of buyers needed to create a new flashlight from scratch.
It needs to stand out in order for a manufacturer to jump on board with the idea.
It’s not cheap to bring a new product into production.
There is far more work involved than making a drawing a couple pixels big, and all the work needs to be paid off in sales.

If it can’t make the sales for whatever reason then you’re left with either building it yourself (like I do with my lights) or paying someone a lot of money for a one-off.

Just an off topic note:
Power density of current 21700’s is the same as the 18650 since it’s just a bigger version of it. The 26650 has lower power density since it’s not made by a major battery company.

The highest I’ve seen available is 4800mAh, which is lower power density than a 3500mAh 18650.

Also 26650s still have much more capacity than a 21700, so unless the goal is a super compact flashlight, if you care about runtime you will go with 26650 over 21700.
If you care about power density more than runtime then you would get an 18650.

I looked for 2 fairly new cells with the same continous discharge rates in order to make it as comparable as possible. Apples to apples, so to speak.

Samsung 48G – 4800mah 10A
This 21700 cell has a volume of 24.25mm3.
This equates to 198mah/mm3

LG MJ1 – 3400mah 10A
This 18650 cell has a volume of 16.54mm3.
This equates to 205mah/mm3

So they are pretty much the same – power density wise. The 21700 is about 47% bigger and has about 41% higher capacify. It’s not an exact scale up, but almost.

It seems Tesla is predicting their new 21700 will have a capacity of 5700-6000mah! I have not seen any batteries with that much capacity. Not yet, at least.

If this turns out to be true, then the power density will definetly exceed the 18650.

So far, I really like this quote from John Peterson.

“Batteries are chemistry in a can and changing the size of the can does not change the energy density or cost of the chemistry inside the can.”

In looking at my older quote above, I checked HKJ’s review of the MJ1 3500mah and it seems it’s capacity is closer to 3200mah and it’s max continous discharge is 7A.

His test of the 48G shows a capacity of around 4650mah and 10A continous.

These may not be the ideal batteries for comparison, but the power density is pretty much the same.

48G - 192mah/mm3
MJ1 - 193mah/mm3

OK. I see that these proposals were not taken quite like I meant them to be.
They were meant to serve 2 purposes:

  • act as showcase of a certain construction
  • be actual, direct proposals

I see that they are seen only as the latter. I’d like to explain the former now.

My main driver when drawing those lights was the goal of having lights that are high-quality, small, powerful, efficient, feature-rich. And cheap.

Do these lights deliver?
Yes and no.

Efficient? They won’t chase Zebras.
Cheap? Not. But not expensive either.
Feature rich? Smart-light makers beg to differ.
Powerful? A mere pop can light delivers way more.
Small? 10180 collectors will laugh.
High quality? BLF has a good track record so far.

Each of the qualities mentioned is relative. But I believe their combination is unprecedented.
Efficient? A bit more than the current BLF lights.
Cheap? There is nothing inherently expensive in those lights. Though features do add cost. Still, I believe the costliest part is R&D. Which is a part of the reason why I drew a family of lights - some costs are shared.
Feature-rich? Charging becomes common. Powerbank is a natural extension, but still rare. Firmware features? BLF shines here.
Powerful? There is literally nothing on the market to challenge them on performance-to-size.
Small? Few lights offer better battery-to-body-size. And all of them sacrifice both features and performance for that.

The key reason why they can pack so much is so little space is a combination of:

  1. LD4/TC style driver
  • delivers lots of current
  • delivers lots of regulated current
  • takes little board space
  • has no high components
  • is fairly inexpensive
  • is slightly more efficient than other linear/linear+FET drivers. Little less than induction based ones. High-vf LEDs help efficiency.

2. Driver integrated with LED MCPCB
3. Button and magnetic charging port in the front part of the head

That’s it. Every other decision I made when drawing those lights is not a key one.

Though some further decisions seem to come naturally from this:

  1. Unibody….better heat transfer. Why not?
  2. You need quite large MCPCB to fit all the components. This means that the head will have much larger diameter than 18650 battery. Therefore I believe going smaller than 21 mm diameter doesn’t really make sense. But going up, to 26650, to 32650, to 4*18650 is just as fine with me.

I simply picked the smallest that I believe was good.
But you said 21700 is not so good at the moment. Is it really?

The top of the line 18650 are actually like 3200 mAh at reasonable current (3A to be precise).
The top of the line 21700 are actually like 4600 mAh at reasonable current (3A to be precise).
The top of the line 26650 are actually like 5600 mAh at reasonable current (3A to be precise).

Yes, I do view them as good. Add to that high-current cells like 30T or 40T for those wanting more fun and it becomes very good. By the time the project is done, they should improve further (f.e. Sony is out of the game still).

21350? It is also a bit of why-not decision meant to increase the potential market to include people who want to go smaller. Anyway, it’s not a key choice.
Dedoming? Shaving domes by the thousand is not really expensive. Shaved LH351D shouldn’t cost more than stock XP-L HI. In fact I expect it to cost significantly less. And anyway, it’s not a key choice.
Magnetic connector? Does add some cost. It is a key choice unless we go further up in size.

Agro, your driver/mcpcb idea is what made me loose interest in your design. It just seems to not make any sense.

Interesting. Could you elaborate on that?

Heat is bad for electronics.

Plus, how can I swap in a new driver with NarsilM on it? Lol

Yes. But what I started with was the concept of the light engine and I validated it with noone but the highest expert on LD4/TC drivers we have on BLF. Led4Power. Only then I started having ideas of making BLF lights with them.
I assume it can be done to work.

Indeed, modifiability is severely reduced with such technique. You can flash different firmware. You can swap LEDs to others with same or very similar pad layout. That’s largely it.
All of that to improve size.
Is it worth it? For me - definitely. But I’m not surprised to see a different opinion. Actually I would be shocked if everyone agreed. :wink:

I think small is over rated. I find my DQG tiny 7x to be too short. When I hold it, my pinkie and ring finger hang off the back. I don’t like that.

Plus I’m not a fan of tir lenses. They are no good for walking at night.

This is why I have no interest in your design and other similar designs. I just have no use for it. Sorry.

That’s my excuse for not talking about it.

Surely that’s not the reason for everyone here to not talk about it.

It’s still good to know it. Thank you. I really appreciate what you said. Because the fact that you said it means that you care.
Frankly, the silence was depressing. I far prefer negative feedback to nothing.

Agro, please don’t be discouraged from posting your ideas here, in spite of what some may say (or not, as the case may be). I am one of the ‘silent’ followers here. Besides, this is BLF and there is nothing wrong with you posting to this thread. You haven’t hijacked anything just because others don’t contribute ideas of their own.

Jason, I disagree with you about TIR lenses. I find if they’re done well, they give me exactly the beam profile I like for walking in my neighborhood at night. Olight S1A is a good example.