New Project Supervisor Here: Line of LiFePo4 Lights

A lot of people still don’t understand the purpose of my deliberate and fanciful design.

kikkoman Well, the idea is to be able to quickly pull out the guts of the flashlight and keep them intact, in order to rearrange what remains in the tube… so you have this:

Now, for this to be legal, it couldn’t be fully functional as a suppressor out of the box. But the design could take it 90% of the way there. The end user, with a Form 1 and tax stamp in hand, could take it the extra 10%. This alone would make it worth a $100 to the thousands of people who don’t want to spend $500 for a tiny suppressor.

However, for most people most of the time, it’s just an innocuous flashlight — a role it would fill admirably. For other times, and given that a lot of people EDC both a weapon and a flashlight… well, this means they’d never be without their trusty little suppressor — if they decided to go to the range or something while out and about.

But you’re right, that plastic sleeve and the resultant thermal decoupling… that wouldn’t work. No biggie. Ditch the plastic sleeve idea.

In summary, it offers two novel and unique capabilities:

1) It runs on LiFePo4 (a truly better battery) in a world that runs on Li-ion
2) It transforms into a suppressor [almost] in a world where people who want to legally build their own suppressor have previously had to scavenge and mix and match parts from all over.

So really, this should be like $100+ per unit. Huge demand potential.

Being pushy and presumptuous is just my style, brother.

My first degree is in Engineering, the best way to persuade a group of technical folks (may they be engineers or other scientific people) would be a prototype. As mentioned above in this case a prototype would be even feasible.

If you’d create a simple light with the concept outlined above and would showcase the benefits to the wider group, I am sure more might open up to the idea. I don’t own a LiFePo battery in a flashlight format, otherwise I’d do it.

I only glanced at the XP-G2 spex, and at 3.2V, current was literally off the chart, so I’d be hesitant to just crowbar the LED across the cell without at least some resistance limiting things.

With a triple, each LED would get about a third the total current, so Vf would be a smidge lower vs taking the total current all by itself, allowing more headroom, just in case your LED would have a higher-than-typical Vf.

And I like the floody beam of the TO46R, so that might serve as a host. Or just drop in a LFP cell as-is. it’d work just like it would with a Li-ion cell that was down to 3.2V.

XPG2 current is less then an amp at 3.2V, but that is a relatively high Vf LED.

A FET driver on full is basically crowbaring the LED across the battery, so this is usually not a problem.

Ah, I already had a hunch. Those spacers… that UNEF thread…
Well then.

I’m always a bit skeptical when it comes to things that claim to fulfill multiple roles as good as the “real thing”. It usually puts lots of constraints on either aspect of the design, and one side often ends up lacking, a pure gimmick or entirely unused. (Where’d I put those baffles again?)

Now, as far as that modular can goes, that could actually fly, although I have no idea about the market and potential demand. Is there anything like the 80% rule that applies? You’d have to ask a lawyer but I’m sure you’d need some sort of FFL at least.
If legally possible, and there’s no such thing on the market, don’t you think it will sell well enough on its own merits?

Thank you DavidEF. The reason I never bought a 10mm handgun is I could see jacking a .45 into it (or the reverse, grabbing some 10mm rounds into the .45). I’m trying to minimize the things I can screw up, and as noted above, super safe = Eneloops.

Now a flashlight that in a shtf scenario could be a suppressor, I’d be in.

Just glanced at and it seemed to show otherwise.

Maybe other resistances (switch, springs, etc.) impacted the circuit sufficiently.

The datasheet info is different from what members here have measured.

The circuit resistance does indeed make a big difference. The resistance drops the voltage as the current increases, but the voltage required to pass current through the LED increases with current. The current will settle at the value when equilibrium between these two factors is reached. In the end, directly connecting an LED to a battery is what we usually do, and it’s usually not a problem.

Nothing to worry about shooting a 10mm in a 45. All that happens is that the case expands and the bullet rattles around and dribbles out of the barrel. Shooting a 45 in a 10mm? Not sure how you’re going to get the 45 to chamber in the 10mm.

So time to run out and get a 10mm or 40s&w :slight_smile:

First and foremost, it would be “just a flashlight”. What other people use it for - that’s on them. And it would be an excellent flashlight. It wouldn’t be marketed as anything else. And yeah, it would probably be wise to talk to a lawyer I imagine before actually proceeding with a project of this nature.

Marketing it as an 80% suppressor, like the 80% AR receivers or Polymer 80 Glocks… that would be begging for heat from the BATF (like the aforementioned have received).
Would it make a great suppressor when legally modified for that role? Probably not. Better than nothing though.

I’m just the idea guy. I don’t have the tools, expertise, contacts, or the capital to make this happen.

The problem is you can make things fool proof but not damm fool proof. If you make a light that takes 2 LiFePo4 batteries some one will put 2 lithium ions in it. They will become unbalanced and catch on fire. You need a light that will cuss at you if you use the wrong batteries. Actually Maglite is making such a flashlight. I looked at the specs and it does not work as well as you think it would. The older model that used 5 cell NiCd also does not work as well as you think it would. I don’t think alternate lithiums will catch on. Rechargeable alkaline and rechargeable nickle zinc never caught on either. I have used both systems. You are correct though a buck only system works quite well. Two stand outs are the pelican dive light that takes 8AA batteries and the Maglight that takes 6 D cells. Maglite Flashlights and Lifestyle Products

According to CREE PCT the Vf of XP-G2 at the top of the spec range is 3.25V at 1.5A current. With the top brightness S5 bin, that gives you a rated 658.4 LED lumens. The XP-L2 goes to 3.2V at 3.0A current. The top brightness W2 bin gives you a rated 1316.2 LED lumens. Obviously, both of those can be overdriven as well. But, you’re at the top of your voltage range already anyway. Of the two, I’d pick the XP-L2 if I were making a LiFePO4 light. :wink:

P.S. - A 10A rated cell could easily power a triple of either of those emitters to full rated current.

It seems that the majority of your argument towards LiFePO4 is this perceived long cycle life capability paired with relative safety.

Consider the following 18650 LiFePO4 battery information pulled from:

Now a Sony US18650VTC5A:

What this tells me is that the Samsung 18650 LFP battery has an original 1100mAH capacity and that after 500 cycles of 10A discharge, it will have a remaining capacity of at least 830mAH.

The Sony 18650 battery meanwhile has an original 2500mAh capacity and that after 500 cycles of 10A discharge, it will have a remaining capacity of at least 1750mAH.

This makes the claim "after one year of use the capacity of the Lithium Ion will have fallen so much that the LiFePO4 will have the same energy density" inaccurate. Assuming you somehow charge and discharge your batteries every single day after 500 days (1.37 years) the standard Li-ion still has over 2x the capacity of the LiFePO4. With a more realistic rate of charging twice per week, that would be 104 cycles a year, and 520 cycles in 5 years. So in 5 years time of using Li-ion it still has twice the capacity of LiFePO4. And if you charge your batteries only once per week that leaves a staggering 10 years and the Li-ion battery will still have twice the capacity of the LiFePO4 battery.

I specifically chose name brand batteries with cycle characteristics of the same amount of discharge capability that are relatively new. If I look at other comparisons LiFePO4 fares even worse with less discharge capability.

As for the safety of batteries the vast majority of accidents/explosions/fires I've heard of have been the result of willful ignorance and abuse of batteries. Or straight up fakes.

Thanks Calvin!

There ya go. Problem solved.

See? That was easy…

Ok. Super.

So, if I understand correctly, the simplest way would be to use this XP-L2 with no voltage or current regulation on the high end. But what about the low end? How to cut it off around 2.7V to preserve the integrity of the cell?

In any case, you can be the LED guy.
I can be the battery sourcing guy. I have some leads on bulk cells.
Now we need a tube-and-thread-cutting and end-cap making guy[s].
Also, someone to source the other odds and ends: buttons, lens, etc.

We don’t need Sofirn or Armytek. We can grow our own!

2,7V would be too low here, especially with LIFePO4.

2,5V would be perfect. Not too low, and not too high.

About low VF LEDs, how about we go with Nichia 219Cs triple setup instead ran at 2.8A max and a CC FET driver?

That would make for an absurdly low voltage capable setup.
And with BeCu springs, you’d be getting the best regulation possible.

Well I was basing the 2.7V cutoff on this chart:

(This cuts off at 2.6V … I added +.1V just to be safe.)

Also what does V-subscript-f stand for exactly?