Would be very interesting to know for sure.
Maybe they have done a simulation on how the light heats up and dissipates the heat?
Too bad I’m not home right now. Otherwise I could have addressed some points about the design and might have been able to make a simulation… (far from an expert though….!)
A degree in thermodynamics is not needed to design a light with a good heat-path, some plain common sense gets you a long way already and Sofirn did not put much effort in plain common sense regarding where the heat goes. Their attention was elsewhere when they designed this light.
Btw, it is “exactly like water where a bottleneck can really hurt the flow”.
Buy once, cry once.
Why not design this perfectly from the start rather than have regrets about it later. I don’t think anyone here would deny that a solid head would have better (even if it is SLIGHTLY better) heat dissipation than a 2 piece head. Will the difference even be measurable? Not sure. But we all know a solid head WILL BENEFIT HEAT DISSIPATION, even if it is a 0.0001 degree less heat.
@Sofrin - if this flashlight is popular, you could use the same design for a 3x XHP70. With that much output, you definitely need a solid head. Make the solid head now and you will not need to redesign it later on.
This is still in the early design stage, before any metal has even been cut. Why not fix it now rather than wait until it is too late?
This thermal issues are discussed very early in the K70 thread as well.
Same design, same problem
Gettin a deja vu here.
What kind of driver will be installed?
Is it possible to have a 17mm sized driver?
If so, that would mean the driver bay can be a lot smaller in diameter. You can then make some nice deep fins around the heat source.
Also, please skip the fins at the top of the head. You can make the head much slimmer or make the reflector much bigger with the same head diameter.
Also, I would change the O-ring from the reflector/head to the bezel.
That way you can make it more space efficient (meaning the biggest reflector in the space available)
I have to say the initial design isn’t that bad. Even the heat flow is not that bad. Yes a threaded connection is worse than solid aluminum.
I think the light will benefit more from better and more fins at the heat source than making the head out of a solid piece.
Even with one XHP70.2 at 7000+ lumen (this is the outout that we are aiming at in this light, right?) we are talking about 60W, this needs serious measures to keep the led from boiling.
For comparison, a stock L6 is a 25W flashlight, at that power level you get away with much more freewheeling in the design.
I asked them about going to a one piece head design. I doubt they will want to redesign it, but you never know.
I also made several suggestions about where to leave extra material in the head.
We should keep in mind that there ARE some fins cut into the sides of the switch area.
Maybe these can be cut all the way around the light?
In looking at pictures of the S70 I noticed that if we add more material around the mcpcb (5), then we can add some fins right where it’s needed most (6).
What do you guys think of that?
MOSFET
Most lights this size use a 28-30mm driver. It looks like they want to use the battery tube to hold the driver in place.
I think we will be closer to 100W unless the engineers find a way to dial it down.
And I’m sure we all will be dialing it back up :sunglasses:
Djozz, I agree with you on the heat dissipation. My point was that Sofrin can use this same “host” for a multi-LED setup later on, without having to design an entirely new light. IF they design it right the FIRST time (now).
That is a good start.
I should enlarge part 6, more aluminium for absorption and more plus larger fins for heat transfer
So JasonWW you are telling me that there is asolutly no difference betwen using a switch or not @17A. Ok i have nothing to say to this.
Also so many people are telling you there is something not right with the thermal design (and a few of them alredy have a little bit of experience). And again regardless of what everyboby says you know better.
Please help me. Whats the aim for this light? Most beautifull Flashlight on the shelf or a flashlight (for modders) with the maximum output you can get for a budget price?
One word regarding the thermal abilities. I remember the same arguments when the GT was made (it is enough for a XHP-35, Thats ok , it will be good. . . . ) but a few people pushed untill the design was improved. Now they bring a modkit on the market with a XHP-70. Thanks to the efford of many. Also a multi-emitter light.
Why would someone build something not as goog as it could be if it is not costing anything or the cost is very little for the improvement they gain.
I got no change in lumens. I was hoping I would. I have extra switches to put in, but they were not needed. :cry:
You are not paying attention. I agree it is not perfect. In fact, I say this many times. I am also right there trying to come up with improvements like everyone else. I think some people greatly exaggerate it’s flaws while I see them as only minor.
It’s whatever you want it to be. Just like with any other light.
This is one of the biggest mysteries in life. I don’t know why, yet it is done all the time. Laziness? Ignorance? Maybe there are reasons we are not aware of.
Before people get onto Jason too hard. I am pretty sure that his personal feeling and what he feels that he can get Sofrin to do are getting jumbled up in his replies.
Having worked with several manufactures, a change like this can be quite difficult to properly explain and get them to make, even if it seems simple to us. In which case I think he is just channeling what he thinks their logic is as I have done as well.
Now his personal opinion I am not so sure on, I think he is underestimating the effect that a proper thermal path would have on the overall usability of the light a fair amount but he seems to understand the gist of the argument.
In a nut shell a proper thermal path could allow the light to maintain a significantly higher output over the long term.
A sign of a bad thermal path is the L6 for example that uses a design much like this (except 1 piece, without the threads) where the switch area heats up much faster then the fins and head. This is proof positive that there is very high thermal resistance between the LED and those fins.
This is made double bad by the fact that the switch is the part you touch, not the head.
Overall if they go with the design they have now my interest in this light will drop to “eh, if I find it cheap enough I might get one but I am not going to go hunting for it”.
Well said TA 
Not trying to be annoying, just trying to help developing a nice BLF worthy flashlight.
Page 2 of the K70 thread.
Here the thermal properties were already mentioned and discussed.
Except that the drawing and post above suggests that the heat is projected downwards which is a bit of nonsense as heat has no direction and will just go the way with the least thermal resistance, in whatever direction that is.
Anyway, we all agree that we need to get rid of the heat on the most efficiënt way.
So fins on top of the head is nonsense, we need a good thermal path around the source of the heat.
My S70 doesn’t really get warm enough in this weather to pass heat to the fins they are only slightly warm even after a substantial amount of time. The S70 has some fins/cut outs around the switch area dont know how much they help they probably need to be bigger. I think the S70 handles heat better then the L6 but that may be because my L6 is clear?
I think heat soaking will be more prominent on this light it will be at least twice the power? My S70 is only around 30w.
We just need enough material to pass the heat to the fins without effecting performance easiest way would be to move the switch or have fins around the switch.
This discussion is getting very interesting, in a very civil manner I might add.
Good and informative info, thoughts, & suggestions. :+1:
.
My thoughts align more with Yokiamy, djozz, & many others as far as heat sinking, heat path, & heat transfer goes. Make it right the first time. It does not cost more to leave metal, it is actually a bit less machining; so cost is slightly decreased.
So make it in the best possible way as far as shedding heat. No valid reason not to.
FORM FOLLOWS FUNCTION
Function first.
Form second. :+1:
JasonWW, thank you of spearheading this project.
Without you, none of these discussions/opinions would be possible.
You are appreciated.