I don’t think “they” are making fake XHP70’s yet but be sure you get the bin and tint that you want.
A XHP50 or even the XHP35 might actually give you more distance an emitter to reflector ratio kind of thing (but less light and less heat).
Best…?
obviously big is better then small.
You could try a Convoy L2: https://www.fasttech.com/products/1601/10002364/1213106
And an XHP70 from RMM: Cree XHP70 N4 1A on 16mm / 20mm DTP MCPCB
(The 6V-20mm option)
That particular L2 isn’t available anymore. But convoy (simon) has made another one, there is a thread over it on BLF.
Supposedly he is going to make a version with OP reflector and 2 cell battery tube so it should be a decent XHP70 light.
As a matter of fact I’m going to use this new L2 w/ op reflector and 2 cell tube to build a XHP70 light :D.
Will the L2 be able to power an XHP70 at full power? or with a new driver?
There’s a new version coming out, possibly with an XHP70. But we don’t know yet.
If you made it yourself, you’d have to replace the driver.
http://www.kaidomain.com/product/details.S024364
Member Jubledum, found this one, he plans on modding it! 
Does that have a pill? Or is the LED mounted on the same piece of aluminium like the L2?
Shouldered aluminum pill.
The XHP70 needs the direct thermal pathway of the L2. It will overheat and die otherwise.
Yeah? Die huh? Well that sucks! :_(
It produces SO much heat. The heat needs to be carried away quickly. The L2 does that nicely.
Come on, how does the L2 do it so well? :~ So your saying that if you use any other Host besides the L2, all is lost? There will be like, XHP-70’s dying everywhere? 
Here I always thought the XHP-70 was a tough as the MT-G2? Could take a licking and keep on ticking, you know like a Timex watch?
I have an overdriven MT-G2 in a Convoy L4, which has the same unibody construction. Even in this case, if I leave it on too long, the LED will die.
The XHP70 will technically work in any light, on any crappy pill, but you’ll either have to keep it on low, so what’s the point, or run it for 5 seconds at a time, or it will die.
Doesn’t matter how tough the LED is; heat is heat, and if you don’t dissipate it fast enough, bad things happen.
Gotcha! 5 seconds at a time, is pointless! |( And an integrated shelf is the way to go, totally agree! Well hopefully the new L2 will be even better than the old one? :heart_eyes: Finger’s crossed! :bigsmile:
Is there a thread of this light? Seems really interesting to me.
An integrated shelf is best, but there is no reason why a pill can’t be made to transfer heat 99% as well. Just that after doing what you need to do to make a pill work like a shelf it’s no longer a pill.
Just take any given pill and use a very high quality thermal epoxy on the threads and you will have the thermal transfer you need. Now of course you won’t have a removable pill, but you don’t get that with the shelf either.
After that it all comes down to the size of the area that you are transferring heat to. The Fins on a light are really only doing one thing, they are increasing the surface area of the light so more air can reach the area that needs to be cooled.
The second option is to build a heat sink into a light. This only works up until the heat sink gets hot (sometimes seconds) and then the heat sink actually holds heat in the light so even after you have turned the light down it’s keeping the emitter heated. A combination of both can be used effectively but rarely does this work if it’s not combined with some way to also transfer the heat to the outside of the light or use some non-passive way of cooling the heatsink, like a fan or other cooling agent.
Well anyway, don’t like your pill? Buy some good thermal epoxy and fix it.
The thermal conductivity of Arctic Silver Thermal Epoxy is 8W/mK.
The thermal conductivity of aluminium is 205W/mK.
I realise there is contact in the threads, but it is mostly the tips of the threads, and more on one edge, when tightened.
Edit: yeah, fins are essential for dissipation.
As I said the integrated pill is best, but thermal epoxy is going to fill in the air gaps that are acting as in insulator. So it’s not a comparison of aluminum to epoxy, it’s a comparison of AIR to Thermal Epoxy or whatever you fill that gap with. Removing the air that is acting as an insulator with just about anything is better than leaving it there and it’s often going to transfer heat faster than the surface area of the light can remove it. Once you have reached that point it doesn’t matter if it’s 8 or 8,000w/mK.
I can take a light that is barely transfering heat and turn it into a light that gets too hot to hold in a flash. Now if the outside of the light is getting hot then thermal transfer is taking place. So it doesn’t matter what you do, or how you do it. If the outside of the light is getting really hot, really fast, you have done all you can do.
Now you can limit yourself to lights with only the shelf if you want. But why should you when there is a proven and effective way of making lights with pills transfer heat faster to the outside of the light, than the outside of the light can transfer that heat to the air? The surface area of the light is the limiting factor. So let’s say that with a shelf it transfers heat to the point where the outside of the light is scorching hot in 10 seconds and with the epoxy it takes 10.1 seconds. How much have you gained with the shelf vs the pill with epoxy? According to you it’s 205/8 but trust me, that is not how it works.
But if you don’t believe me then don’t bother with it and stick with the limited selection of lights that have shelves. What do I know, I have only built a thousand lights or so.
Ps, I’m not trying to be rude, but this is one of my pet peeves.
I agree with some of that, but I still think the difference between pill+thermal Epoxy and unibody is higher than you suggest.
I know it’s not 205/8, and I tried to express that at the end of my previous post, but, I still think it’s noticeable.
Also, once I’ve got an MTG2 at 7A on a noctigon, with Arctic Silver paste to the unibody shelf, I am very much chasing marginal gains. To me, what you referred to as the 10s vs 10.1s is still a noticeable difference, though I still think it’s more like 15-20s. Maybe it’s overkill, but I stand by unibody shelves. I’ve had a pilled UF C8 and a Convoy L4 both running XM-L2’s at 2.8A, and the L4 got hot twice as fast as the C8.
I do have and use some pilled lights, they just don’t see much power (a couple of cheap supermarket bought lights, a Ti3, that sort of thing)
I know you have so much more experience than me, but discussion and learning to improve our knowledge and our light building is the whole point of BLF! 
That’s fine and since you see that difference as worth it, then it is worth it to you, one second or a dozen doesn’t matter really. Only your preference does. For me I just don’t see the point is chasing marginal gains if it means that I’m limiting myself when it comes to lights to buy. If it’s the same basic light at the same price or close to it then I will go for the shelf every time. Especially in larger lights. The smaller the surface area the less difference it makes. The thing is that I have found some really great reflector designs on lights without shelves and I wouldn’t turn my nose up at them because they have a pill. Some of the really cheap lousy designed lights happen to have some of the better reflectors. (Don’t even get me started on plastic vs aluminum reflectors)
Think of it like a drag racer with three inch tires. It doesn’t matter if it’s 200hp or 1000hp the limiting factor is the surface of the tires, not the horse power. But a BIG light is like having really Fat tires on. You can now use that 1000 horse power. With a small light you are going to heat that outside fast with even basic thermal transfer.
Also a trick that I use is to increase the size of the Pill itself. Let’s say the pill is only 1/8th in thick, well even if it was perfect like a shelf it’s still only able to transfer heat through that 1/8 inch spot. Now add a copper washer or something similar to the bottom of that pill and make it 3/8 of an inch thick and all of that up tight against the side. Again this is something to do on any light, shelf or pill. I don’t normally bother with smaller lights. I do this with Sky Ray Kings all the time. I have turned the pill into a shelf and then added a half inch under that. They get smoking hot FAST. I also have a SRK that has a 1 inch copper pill. No other light in my collection gets hot faster than that one, but it stays hot too and is a lot heavier. But even though it’s noticeably hotter faster it’s still only a few seconds faster and I have built an identical light with the only difference being the pills and tested them.
But I do get it, you notice that the light is transferring heat faster and that is a concern for sure. Morehotterfasterbetter. Plus it’s a lot less work if you simply buy one in the first place with a good shelf.