Good point. Heat finning can significantly increase surface area at the hottest parts of the flashlight. I did a quick calculation to estimate this.
2*d*pi*D is approximately the extra surface area of one fin. d is the depth of the fin and D is the outside diameter of the light. This approximation is valid when D is much larger than d.
p*pi*D is the area of a section of the surface of the flashlight if there were no fins. p is the fin pitch or distance between fins. So this area is of a small section of the flashlight that would contain one fin.
Then, a relevant quantity is (total surface area with fins)/(surface area without fins). This is just for the section of the light where there is finning, where it is most important.
So this quantity is (2*d*pi*D + p*pi*D)/(p*pi*D). Simplified, we get (2d+p)/p.
For example, with D=55mm, d=4mm, p=4mm, and 5 fins, approximately 6908mm^2 of area is added, and this increases the surface area of this section of the flashlight by a factor of 3.
Exciting Times Ahead before it is done.
Endurance To Annoyance since I want it now
All progress here in the thread.
Ah that reminds me. V5 driver is ready, too tired, will update OP with latest info on it tomorrow.
Something to think about while y’all are crunching fancy formula’s for heat sink fins…
How do we use a flashlight? Don’t we hold it horizontal in front of us? So the heat rising up from the fins on top is conducted away by air, what happens to the heat on the bottom side of the light? My point being that air flow doesn’t happen the same all the way around the light in a typical use scenario.
If more cooling is needed it would be far better to stay with the current fin design and simply stretch the head area 10-20mm to gain shelf mass and extra cooling fins. (Yes, make the light longer)
Funny you are.
Well, if you want to have 100500 lumens for 10sec., you are right. There will be great difference in temperature of parts and main profit will give dtp pcb.
But if you wait 20-30 minutes all parts of light will have same temperature with 5 deg.C from pcb to tail. Same tepmerature of whole host means same difference between host (heatsink) and surrounding area and same influence on heat transfert whenever you increase host area.
[quote=EasyB]
10*3.14*(55^2-51^2)/4=3330mm^2=33sq.cm., that allow you put extra 1.5W-2.0W for long time.
For example Ф50*135mm tube is 3.14*50*135=21200mm^2=212sq.cm.
Your fins are much more that 1-2%, but there is no place for 5 extra fins (5*4mm fins + 4*4mm place between them - where did you find 36mm of free place?)
All very good arguments, but frankly, without making huge changes to the overall design of the light, it’s not going to make much difference.
Including this: Unless you are in a cold climate, you won’t be able to leave this light on max for 20minutes without over heating. It’s simply too much power in too small of a package.
To clarify, in my calculation the pitch, p, is the distance from the start of one fin to the start of the next fin, so it includes the fin and the space between the fins. So 5 fins would be roughly 20mm.
d is the radial depth, like if you put a ruler perpendicular to the flashlight surface. With d=4mm, if the OD is 55mm, the diameter at the bottom of the fins would be 47mm.
Wauw!
That Lux-RC (search image ) is art! That is a very cool design
Did I read something about adding a little bit of length?
A few of these extremely deep fins between led area and driver area would certainly help in cooling
But would it still be a soda can light?
Did I mention I am very tired? Haven’t slept more then 1 hour last night due to splitting headache so I could be getting carried away a bit too far here
Another part of the ‘fin equation’ is how machining/turning works. With square-cut fins the tool only cuts on it’s one end; easy to make/maintain/use/set up and is durable. Tapered fins use tooling cutting on two sides at once; more costly tool/harder to use and maintain/cannot cut as quickly/harder to set up properly/higher wear on tooling. Thus probably an increased cost, which we’re probably pushing the limits on now. Numerous thinner fins would work better too, but would be much more easily bent or damaged.
A good discussion and interesting, but I fear it isn’t going to happen here due to cost. And no reasonable amount of change to the finning will make this light run cool enough to walk away from in operation so at best you’ll only get a little more time before ramp-down needs to happen. In the end everything is going to boil down to cost, which many have noted they won’t accept any substantial increases of. But if the Q8 team wants to try for different finning I’m still in.
When this light is done, can we also design a nice belt pouch for it?
I bought a military flash bang pouch to keep the Supfire M6 from Richard and that thing BARELY fits in there. I had to loosen the strap on the buckle all the way to where it only goes through one opening like this:
[quote=MRsDNF]
I have just finished building a quad SRK up to test Tom E’s driver and find out what sort of spread the XPL emitters would give in this light.
I’ll start with the driver. Wow. What doesn’t this driver do. I’m probably the last person to ask to test a driver like this as I get lost in my driveway let alone try to get my head around the workings of this driver. I’ve been playing with it outside in the shed, the driver hooked up to an led and my power supply and got so lost.
I eventually had everything together to assemble the SRK when I dropped the lens and yes it shattered, me as well.
The light is now operational after waiting nearly three weeks for a lens. I started with this light. The XPL leds sit on 16mm Noctigons which themselves sit on a 5mm plate. The depth of the head was machined to suit the above stack. 20AWG wires channel the current to the leds from the Narsil driver which has the latest firmware. The stock springs in the tailcap were given a bypass with 18AWG wire.
Back to the programming. I was still lost and had all sorts of modes working but had no idea how I got there. Yes I did have the instructions in front of me.
I took the instructions inside along with the light to a warmer part of the world than outside and sat down in front of the TV in my comfy chair (no pun intended ) and the instructions clearly laid out in front of me.
No luck. There was just to much going on with flashes and my poor brain not deciphering the flashes they were seeing.
Looking up I could see the light flashes reflecting on the tv screen (the tv was off). H’mm, starting again I watched the reflection of the flashes on the tv and it all of a sudden made sense. For some reason my fuzzy brain could decipher what the eyes were seeing on the tv screen, yes today the tv was a real idiot box.
The difference being was that I could clearly see the light and count accurately the flashes to work out where I was, working with the instructions.
awesome light steeve
and the comfy chair heh
^ I agree with this. The light is just too powerful for its size to be able to run constantly on high. In my opinion, proper thermal regulation in the driver is the only way to prevent overheating in a small, high power light that is available to the masses.
I think this is a good idea. It would have to be a separate accessory for cost reasons, but I think Thorfire could make a good one and sell quite a few
I've got some nice mil pouches that fit SRK's well. Posted bout them wayy back. The Molle 2 clip pouch works well, even one for grenades fit -- hhmm...
) and the instructions clearly laid out in front of me.
