I like the idea of a screw in pill. deals with heat issues and makes the whole flashlight more sturdy.
Most of the exploding flashlight reports I have seen were lights with multiple CR123s.
They are dangerous when used in series.
Sorry if this sounds insulting, it’s not meant to be 
A drop-in has three parts, some metal bits, an led and a driver.
It is the driver that has the input voltage range not the led,
It is the driving amps that dictate the voltage used by the led.
XM-L2 uses from 2.84v at 350ma to 3.43v at 3000ma - for 1048lm
MT-G2 (6v) uses from 5.61v at 350ma to 6.42 at 3000ma - for 2126lm
So for a bigger input voltage range an XM-L2 with a voltage (at 3000ma) of 3.43v will give you a 3v bigger range than an mt-g2,
eg: driver input using an xm-l2, 3.5v to say 12.6v (3 li-ion) is a range of 9.1v where-as driving an MT-G2 is 6.5v to 12.6v a range of 6.1v.
Cheers David
You keep avoiding the question. Why do you want to run 4 CR123a’s
The extension tube it to allow 2x18650.
If you really must run more than 2 CR123a’s, then by the smaller CR123a extension tube which is half the length. This + a standard L2 body will give you length for 3 CR123a’s.
But it still makes no sense to do this.
That’s because the Mt-G2 is a different emitter with a higher vf. It’s not the same thing to try and compare.
Yeah, because having something 4 CR123a’s long is an ideal pocket size :bigsmile: 
Maybe he wants to be able to use the extension, but use CR123’s as the source of power, for greater flexibility. If you just pay attention to what he is actually saying, it is not that he wants to run a LED from 12v per se, it’s that he wants the greatest amount of flexibility with choice of cells. I tend to agree that a driver that could take input from 2.8v to 12v would be a pretty cool thing. I know it will be terribly inefficient. But, efficiency may not be the most important thing to some people. In the OP’s case, he wants to not have to depend on 18650’s for powering his flashlight.
Once again, you’re looking in the wrong direction. Not talking about the LED itself, but the driver. If he could get that driver in a P60 drop-in with an XM-L2, it would satisfy his requirements.
Yeah, well, we all got different ideas about what “carry” means. But, that’s not what this thread is about.
A P60 ground-up redesign with a pill that screws into the body/head is just not going to happen. It would no longer be a P60, its parts would only fit itself, which is the opposite of the one thing a P60 is good at. Even a non-threaded pill that was a slip-fit/light press-fit would kill the P60's one party trick, as the ID & depth of the bore in the head is different between just about every single P60 host version. A pill sized to fit a L2P wouldn't fit a 501B. There are even differences to the inside of the head on different batches of the same model, because that dimension is not critical when using P60 parts.
LD-40! (17mm Buck driver, 3-16.8v!) - too tall to fit in a P60 pill, though.
If you pay attention he says he wants to run 4 x CR123a and has said so in more than one thread.
And using a battery tube for the sake of using it is kinda dumb if you don’t understand why you should or shouldn’t.
But it’s all relative, the driver for the MT-G2 is thus, because it’s a different emitter with a different vf, not to piss off one or two people like the op that want to use it something else.
Here is the thread I was looking for Good deal - TrustFire TF-R2 Just a different host to use P60 thread ins.
The 16340 size is nifty in that it has rechargeables and primaries in the same size, same as 14500(AA), and 10440(AAA), but the capacity of all of them pales in comparison to 18650 cells. If you are worried about an emergency then carry extra cells. A wide input voltage driver for single LEDs in a 17mm size capable of 3A or more isn’t in production (yet) but even if it were you seem to like the adaptability of the host for different cells but would rather carry a pocket full of empty tubes than a pocketful of cells??? This is odd. Odd is okay by me but a bit inconsistent. In an emergency I want it on now without having to fumble for it. Would you empty boxes of different caliber cartridges into a drawer with a bunch of different empty magazines? Threads like this can get a bit rude at times and it’s generally not the intent so keep asking and reading and plowing ahead with your ideas. You will either change your mind or change the world.
Actually I have been thinking that this thread has reached the point where it is beating a dead horse as I do not see a new design of drop-in happening unless a major maker decides to develop something or the military demands and funds it. Otherwise it is not going to happen. The P60 was designed long enough ago so it was a fairly powerful incandescent bulb and reflector combined for one makers flashlights which also proved adaptable for modification to convert it to LEDs when ones suitable for flashlights evolved. I doubt if history is going to repeat itself in this case.
Did Surefire public domain it or did they not patent the design or did the original patents run out, I am not sure? It became a semi industry standard adopted by many manufacturers. However it has never been main stream as historically Surefire has sold primarily to government agencies such as firemen, police, EMT and military so far as I know. They are interested in functionality and reliability, not necessarily state of the art lights. The hobbyist market such as we are is probably way under 1% of the total market so for most makers we are lost in the noise. Unless there is a perceived major demand for a new readily upgradeable flashlight then a new and better modular flashlight is unlikely to happen.
Just look in Home Depot, Lowes, Walmart and similar major flashlight sellers and see what is being offered. Most of it is CHEAP lights intended to be fed alkaline batteries rather than lights of interest to members. That is the market a new drop-in light would have to compete and succeed in. To me very unlikely.
You guys are getting a little ruff. I believe the original poster is new to the light scene and is looking for some guidance. P60 might be a little dated but it’s still got lots of potential for the new or old hand modder. It’s what I got started in and still use. With a good search over at CandlePowerForum you can find tons of host and dropins that have been made, modded or shoved together over the last 10 years. It has slowed down a lot over the last 2-3 years. SolarForce being the maker of so many different parts seem to have dropped about half of the flavors in bezels, switches and heads. Other makers have dropped out of sight all together. If this thread was 5 years ago we would be all over it with a 1000 post by now. But its not and the original poster is starting now. I think a group hug is needed here.
+1. With all the talk of how many lithium (rechargeable and primary) can be put in series by the OP, it is well worth the pause to consider safe practice in doing so. Not sure our OP is aware of the safety protocol required to use these batteries in series.
I recommend, considering the ‘emergency’ use requirement, stick to single cell usage. Really does simplify your requirements as well.
Were they CR123’s or RCR123’s?
Sorry I wasn’t clear. You are right the driver has the range. I meant matching a specific LED with a wide range driver.
The range of the SolarForce drop ins are .8 - 4.2v matched with a XP-G that works with a CR123 or a RCR123 (I’d like to see it matched with a XP-G2), 2.9 - 9.v that is matched up with an XM-L or XM-L2 that works with 1 or 2 18650’s or 2 or 3 CR123’s or 2 RCR123’s, and 4.18.v matched up with a XP-G (I’d like to see it matched up with a XP-L or maybe a MT-G2) and works with 2, 3, or 4 CR123’s or 2, 3 or 4 18650’s. So I can squeeze the most light out of each configuration. I like the 2.9 9.v with the XM-L2 but I can’t use this with 4 CR123’s or 3 RCR123’s so I have to move up to the 4. - 18v. and it seems like a step down to be able to use 3 or 4 CR123’s and have a XP-G LED where with all those batteries I’d prefer an XP-L or even an XM-L2 with a smooth reflector.
I guess it is because I can’t predict the future. I may have fully charged 18650’s or I may be in a situation where I can’t recharge my batteries and all I have access to is CR123’s.
I have a UF Wf-501b, any drop ins for it, especially a 365 UV?
Wouldn’t it just make sense to maybe buy a multi AA light like a D40A etc. and just keep the P60 light as a normal 18650…
WE just don’t share the same mindset about when a flashlight is needed. Your thinking what do I need to deal with a problem right now. I am thinking what do I need if I am out for a week used all my rechargeable batteries and all I have access to is what I can scrounge from a store (which may or may not be open for business.) I’ve had to walk down 30+ flights of stairs in a skyscraper in the dark during a black out. So having something like the P60 on my person is better than the most efficient flashlight back home in my garage. I’ve been in a train accident where the car goes dark and a flashlight is a great help. And I’ve been in snow storms where the power goes out for a week and there is no ability to recharge and I have to find non rechargeables batteries to have light. So although it might not make sense to you it is because I am trying to prepare for the unknown future, that’s all.
First, yes I agree we have gotten off track and are beating a dead horse.
Second, I also agree that the technology has been changing rapidly and most manufacturers are not designing state of the art machines YET. But just like tube radios were replaced by transistors these flashlights will eventually be replaced by more modular more efficient hosts and drop in (or maybe the term willl be changed to screw ins by then.)
and Third, yes it is sad that when you see what is being sold in most stores. Flashlights with half or less power sold for 3 times as much as what we pay. Unfortunately, that is nothing new. Most people who buy computers from a retail store are buying machines that are already obsolete. Yes they get the DVD burner and can get on the internet. But the chipset is already over taxed because it is the wrong chipset for the demands of the next 4 years. So when buying a flashlight or a Computer know what you are buying.
I really thought when I started this thread it would find people who have lots of experience building drop in and in the middle of their last build said to themselves, damn I wish xxx would make this xxx piece like this to make it easier to assemble. I though people would contribute all their accumulated ideas and in theory we have some radical designs for new pills. And maybe one or two of you who are really good with tools and have access to a workshop might even make one or two of these designs and post them. Maybe it would actually amount to a commercial design but I thought it would break some new ground, just for the fun of it. But I agree the thread is pretty dead.