Optimizing Tactical Flashlights With 16340 & 18650 Batteries

I’m glad this video exists

Umm…two AA batteries is 3 volts

Cr123 has no business in anything other than a weapon mounted light. There's just no logical reason to not use an 18 650 flashlight for pocket carry. Its alll pros and no cons with 18650 and the pocket carry edc segment of lights imo.

I can't get 18650 batteries to fit in my surefire that takes two 123As.

Sneaky sneaky! I like it! Off to Amazon to order 16340s Thanks man! My SFs have been bleeding me dry for way too long. To the point where they've spent too much time in a drawer without batteries in them over the years. This is awesome!

the guy shining the light into the camera needs to watch the video

So wait it seems like the Olight baldr pro has 2X cr123a batteries and they are in series, that's 6v won't the 7.4v of the 16340 batteries fry it?

18650 is the original laptop battery cells, and its what are in teslas (until recently). they are the most mass manufacutred li-pol battery form factor and have the cheapest economies of scale (btw, tsla batteries are actually panisonic in the us).
thats why most flashlights are 18650 based. all Li-pol batterys can be assumed to be ~3.7 volts per cell, yes they charge to 4.2v but its kind of like a spring that can get stretched out past its full length and not become damaged/yield. 18350 (35mm long, 18mm fat) are the correct versions of "half" 18650 (65mm long, 18mm fat). this is because most mfg have to take into accout the redundant protection chips people add to their 18650s now which can bring them up to ~75mm long).
all LED's need a specific voltage to be run efficiently, and then you can usually crank up the amperage pretty high as long as they dont burn up. most led's used in flashlights are all made to be most efficient at ~3.7v. most flashlights that cost more than 10$ however, this doesnt matter. many use a built in computer chip called a micro controller that uses a buck regulator loop inorder to keep the voltage the LED's see constant. this looses ~5% capacity and adds a tiny slow discharge, but is preceived by consumers as higher quality or something. because of this, many flashlights that take 18650s can actually be ran with 2x 18350's at double the voltage, even though the LED's are "rated at 3.7 volts." rated voltage is a made up number by the manufactures. if you want to know what a flashlight is actually rated for, find the part number of the microcontroller and look up the data sheet. example, sofarin 3.7v s25d, "rated at 3.7v", look up the attiny412 micro controller data sheet, it goes up to 6.5 volts, which means you can probably get away with overclocking it at 7.4v.
this is all very complicated…. normally you cant use "milli amp hour" as a shortcut for capacity, but in the world of Li-Pol batterys, u can because theyre almost all 3.7 volts. also the lumen brightness will be proportional to the "power" output by the LED's, which you can approximate by multiplying volts x amps. theoretically an 18650 can produce the same power as 2x 18350's, but in practicality, the 2x 18350's will usually be brighter but drain the capcaity more quickly. this is because LED's tend to exponentially increase brightness with voltage but have diminishing returns or logorithmic relationship with current. but voltage is what zaps LED's right away, and amps is what cooks them with too high temp eventually…. but as i said before, most microcontrollers will prevent this because they have a boost circiut which would convert for example (2x 18350) 7.4 volts @ 10 amps, into 3.7 volts @ 20 amps, which would be brighter but as a side effect safer for most LED lights on the market over 10$.

cr123's and 16650's should go straight in the trash imo if u ask me. 16650s have like half the capcaity of 18350's lol, and they fit in the same flashlights

I have a large maglite type flashlight that is billet aluminum that ran on D batteries and doesn't work. I have a new knock off laptop battery, an led headlight buld, a type c rechargable+disposable, vape. I don't want to throw them away they are in my junk drawer. Thinking about building this and if I have enough parts.

For my Surefire G2x and any flashlights that take CR123As you can use a 16650.

You will lose some brightness but you will gain run times and I cannot to my eye see the brightness loss. Maybe if I had two G2X to compare them too I would see it but I dont.

I use Orbtronic batteries – for their 16650 you are looking at 2190 Mah versus 900 Mah of the Surefire branded rechargeable.

Mind you the Surefire branded rechargeabe 123s you are looking at a solid 6.4 volts versus 4.2 volts off the charger so you do get less power but its not like you are getting 20% less power. Its barely noticeable for me to my eye.

If you are going to use the 16340s make sure you are charging no higher than 3.7 as a lot of current chargers charge at 4.2 and you may be putting too much into your flashlights.

16340 can use at Surefire EDCL1-T

Ive taken all my surefire weapon lights and bored them out on my lathe to fit 18650's soooo much more convenient.

My Browning VXT takes 3-123a’s. I love it, but the batteries discharge when the light is off…?

not sure how your last recommendation works. Two 123As or two 16340s stacked would be supplying 6V or 7.4V respectively, to your light. Replacing them with a single 18650 would knock supply voltage down to 3.7V. A 3.7V supply seems like, if your light worked, it would be running at half power. Sure that would increase the longevity of the charge and even the life but at the cost of lumens, which seems to be what this video keeps referring to.

Brands like Surefire that still persist with outdated technology like CR123A batteries baffles me, I understand some workplaces guys get them for free, but CR123A's get burned through so quick and are an environmental waste, at least make the light come with a rechargeable 18650 with the CR123A option (some do). Imagine if Surefire with their reputation dipped their toe into rechargeable 21700 market with lights at 2000 lumens

i have a strong laser pointer and i have a question. will 2x 16340 perform better than 1x 18650? im asking because if u add 2 16340 u get 7.4V where as if u add 1x 1650 u get 3.7V

16340 batteries will not work in my Surefire 6V Scout or my Airasaka 300. Airasaka specifically says the 16340 is incomparable with the 300 series light. Surefire said 16340 were compatible with their lights but I haven't found it to be true with all of their lights.

Idk if I’d put those in my eotech

You forgot to mention the 16650ies. In flashlights that need 2 CR123 ies in most cases they fit and work .

But the 16340 are only 650 MAh. That's less than half the capacity of a traditional lithium battery.
Looking for a rechargeable for a smart lock (August 4th gen), and this looked promising, but not if it only lasts a few weeks instead of several months.

so what is better? 1×18650 or 2x123a??? for max output power

I need a power management solution for all the batteries that I carry for all of my tactical equipment. I would love the ability to recharge a single type of battery, either 18650 or 16340 I don;t care; but I need them to power my rifle light, pistol light and NVGs power pack. A single battery type that powers ALL my needs.

You'll burn the circuitry real fast

16650 will often fit and work where an 18650 is too big.

surefire g2x, tactician, fury, elzetta bravo.

streamlight 2lx is nice and can take a wide variety of batteries.

keeppower and orbtronic make great 16650 batteries.

a 14500 is a 3.7v aa.

too high of voltage can blow your light and it does get hot fast. good luck

What lights do not run on these batteries ?