Very nice! First time I have seen it documented like that. I have the exact same light (had it a week) and my unscientific method mirrors yours, sans the actual temperature measurements. I did 10-12 minutes instead of 20. Noticeable difference in holding comfort between wrapped/unwrapped. I also noticed my Black L2P gets much, much hotter than the identically wrapped grey L2.

Looking at the graphs, the temperatures are still rising after 20 mins on both.  I wonder at what temperature will each flashlight finally stabilize.

Question is: is a 4C difference a lot? Sorry for sounding ignorant but unless it results in a massive drop of lumens, is there a point in doing this?

Ive noted the temperature differences by touch after copper-wrapping my P60's. Its nice to see some empirical data to back it up. Good job Lothar!

xed888 wrote:

Question is: is a 4C difference a lot? Sorry for sounding ignorant but unless it results in a massive drop of lumens, is there a point in doing this?

The only temps that have a direct effect on lumen output are those at the junction, and those of the cell. 

Temp increase at the junction will cause lumen drop, temp increase of the cell will increase cell efficiency a bit, until permanent damage occurs. 

With the ano working as a thermal barrier, numbers would be different on a bare host. 

Great test, thanks for sharing. 

xed888 wrote:

Question is: is a 4C difference a lot? Sorry for sounding ignorant but unless it results in a massive drop of lumens, is there a point in doing this?

The idea is to draw the heat away from the drop-in.  By drawing the heat out and into the host you are assisting with keeping the light running cooler.  In this test the light was placed on a table, probably without any air circulation to assist with cooling. In real world use the light would be in the user's hand and the hand would work as part of the cooling system once the outside temperature of the light exceeds the person's core body temperature.  In this case, the better thermal path would allow more heat to be drawn out from the system into the holder's hand and into theatmosphere and the light, as a whole, would run better because of it.

xed888 wrote:

Question is: is a 4C difference a lot? Sorry for sounding ignorant but unless it results in a massive drop of lumens, is there a point in doing this?

Yes it is, just compare the die area / dropin surface with the surface of the host. 4C difference at the host can translate to multiple times that at the dropin/die.

The copper sheet you used had any adhesive?

Could you give a link, please?

you should do a test with a luxmeter and white room (bathroom test) to see how much light will you lose with can stripes versus copper sheets

Lothar wrote:

Here is the link: http://www.ebay.com/itm/COPPER-Sheet-Metal-Tooling-Foil-6-x9-x-003-40gau...

 

You start by cutting a 0.5-0.75" x 6" strip. Then you just start wrapping the copper sheet tight around the drop-in. When you're finished, keep it in place with one hand, and try to force it into the P60 host while turning the drop-in in the opposite direction as which you wrapped the strip. If it doesn't want to go in, trim 0.1-0.25" from the 6", and again try to force it in the P60 host. Repeat until it fits

Many thanks.

They only ship to USA. Time to look a little bit more in ebay!!

Lothar wrote:

xed888 wrote:

Question is: is a 4C difference a lot? Sorry for sounding ignorant but unless it results in a massive drop of lumens, is there a point in doing this?

In short I don't think it's going to make a huge difference, but it is going to make some difference. It's exactly like adding an aftermarket air filter to a car, swopping your flashlight's lens out for a UCL lens, redoing solder points, and all the other things we do in this hobby. If a flashlight is just a light to you/a person, then wrapping the drop-in is going to be pointless, because an XML T6 is already more than what you need, but if you/a person are a flashlight enthusiast seeking to optimize and get the most efficiency out of the LED and battery, then it makes sense to copper wrapping the drop-in.

A more thorough test would have been to measure the drop-in and LED temperature directly. But any extra heat that the copper wrapping can draw away from LED will mean more lumens, even if its only 10 more

And another point, the wrapped host only used 0.23v (4.15 - 3.92) in 20mins, whereas the unwrapped host used 0.28v (4.16 - 3.88), which means that because the wrapped host dissipates heat better, the LED can operate more efficiently. Again, it is a small difference, but it's 17.8% ((0.28 - 0.23)/0.28*100) more efficient.

Thanks, Lothar - puts it in perspective. I was confused a week or so ago with a thread saying that wrapping doesn't make much difference, and now I see why it does, particularly if you use the light for extended periods, which I do. When I owned my Mustang LX 5.0 Pocket Rocket, I would do lots of little things to boost HP or handling, often by 1-5%. They do add up.

Funny, the ebay link to the copper foil is the same stuff they sell at Hobby Lobby for $9.99 a roll, but the roll is 12" x 30". Probably a lifetime supply for me.

Bringing this back from the dead, how for down the spring or up the reflector did the foil go? Any pictures to it wrapped before you put it into the light. Just got my first P60 and drop in and like it but want to make it even better.

bose301s wrote:

Bringing this back from the dead, how for down the spring or up the reflector did the foil go? Any pictures to it wrapped before you put it into the light. Just got my first P60 and drop in and like it but want to make it even better.

Based on the other posts, the foil likely starts at the end of the taper, and goes down roughly .5 – .75” from that point.

bose301s wrote:

Bringing this back from the dead, how for down the spring or up the reflector did the foil go? Any pictures to it wrapped before you put it into the light. Just got my first P60 and drop in and like it but want to make it even better.

You might want to take a look at the video in this post:

http://www.taschenlampen-forum.de/modding/14006-drop-modd-video.html

bose, I hope this picture helps to illustrate:

This is my L2 with an unknown drop-in gifted to me by mitro. The 40 guage copper strip is 18-20mm wide, cut from a roll I got from Hobby Lobby. As you can see from the photo, this width covers from just over the reflector curve down to slightly over the spring. The actual flat spot on the drop-in is about 16mm. Doesn't really matter because the actual contact area (the dark strip in the center on the drop-in) with the host is about 12mm. After much trial and error, I settled on the 18-20mm width as narrower widths tend to slip when pushing the drop-in into the host. I used the Ceramique as a kind of glue to hold everything in place. It's very thick and sticky, so only a small dab is required, plus it is after all thermal paste, so it should help or at least not hurt heat conduction of the copper.

Start with a few small dabs to hold the strip in place on the drop-in, then start tightly wrapping it around. I put another dab of ceramique in there about every two wraps. With 40 guage, 6-7 full wraps will be adequate, but the exact cut out is different for every light and takes some trial an error to get right. After finish the wrapping, I'll continue to twist it in the direction of the wrap until it is completely flat and very tight. Then peal back the last 1" or so, spread a thin layer of ceramique on it to hold it in place. Then twist again until it stays flat and in place. Be careful not to get the paste near the edges, as it will spread out and get everywhere.

When you push it down into the host it should be a verrry tight fit to assure contact and thermal conduction. Use a screwing motion, going in the direction of the wrap so it stays tight and in place. The wrapping above is nice and snug. The wrapping on my L2P is so perfect it takes all my strength to remove it from the host.

Hope this helps. Expect to have to wrap/re-wrap and cut the strip until you get the best fit.

Awesome work thanks for sharing.

E1320 wrote:

Awesome work thanks for sharing.

The P60 drop-in is faulty by design, as far as heat transferral is concerned. Crikey, all those bloody drop-ins are designed very poorly!

Have you ever taken apart one of those? No offense, as I do know a lot of you probably have. That brass pill which screws into the aluminium reflector, well, to be honest – I couldn’t think of a design more flimsily. Subsequently, I’d add as much copper to the pill as only possible; press-fit, then add a thin line of solder, just to make sure.

Next comes the design itself: Heat, for that matter, is mostly drawn off by the wrapped aluminium reflector to the head of the torch. Which, in turn, is not the part where the heat actually builds up – that would be the junction point between the emitter star and the pill, or more comprehensively, the pill by itself.

Now, you’d still have to overcome that terribly bad barrier of threads between the pill and the reflector, to effectively draw off the excess heat.

Think about that, sometime. Standard LED P60s are awful to heatsink properly.

Oh, just to add one more thought – a thought, really, an idea, nothing proven by myself, so don’t club me to death if I should be wrong:

Copper is only as good as the alloy it will come as. Meaning: Pure (chemically pure!) copper = excellent, use it if you can get your hands on it!; industrial-grade-copper (a.k.a. “what-the-machine-shops-with-all-their-fancy-CNC-lathes-usually-have-piled-as-bar-stock”) = save your effort and take your commercially available aluminium bar stock, as it can be machined much more easily, and transfers heat at the same rate as a generic copper alloy.

please take this into consideration as well.

Oh, on a side note: Of course!!! I do use copper with a pill rather than aluminium – just for the sole factor that soldering copper to brass is SOO incredibly easy, compared to soldering aluminium to brass.

FWIW,

Simon

p.s.:

your best bet would be a conically shaped liner bushing, and both the pill and reflector re-worked on a lathe to match that conical shape of the bushing, then hand-lap, then press-fit everything together. Sounds like a lot of work? It surely is, at least for me. Angles of any kind I have always found terrible, be it on 3ds max, AutoCAD, Nemetschek Allplan CAD and even by hand.

As I understand it if you specify c101 when ordering a part at a machine shop then it will be made of 99.9% pure copper. 

scaru, I’m looking for a source myself. Things aren’t as easy in continental Europe as they are in the US, or in the UK.
May not even legally hunt down mice on my attic or in the garden with an air rifle over here.

I'm pretty sure this company ships to europe. 

oh my, intl’ shipping – I’d be horray about it, if the suspension parts for my 1967 Mercury hadn’t cost so much already!

ta, bookmarked for next month!

I wonder what is the point in wrapping the reflector with foil. I tend to wrap the bottom 5 mm of the reflector and the base of the pill but the spring gets in the way. Sometimes I remove the spring as it doesn’t serve any purpose as far as I can tell.

the larger spring tightens the reflector to the pill i am pretty sure if u take it out and play with it

I also got 50c with aluminum foil. I got about 43c with no Aluminum foil showing the foil does indeed help a good bit. Don’t see any benefit using copper. Also, I didn’t see your temp with no foil?

Keith

budynabuick wrote:

I also got 50c with aluminum foil. I got about 43c with no Aluminum foil showing the foil does indeed help a good bit. Don't see any benefit using copper. Also, I didn't see your temp with no foil? Keith

Ha! Great idea! How many wrappings did you have to do with aluminum? Wikipedia says that standard aluminum foil is 0.6 mils thick and heavy-duty is 0.9 mils thick so you'd have to wrap 3x-6x times the 3 mil thick copper. Also, the aluminum might be too thin and rip as you tried to force it into the body. Did you have this problem?

BTW, the OP lists the full temperature rise of both unjacketed and copper-jacketed versions in the graph. It looks like 44C 46C to me.

I’ve been using 24 ounce Monster cans as they are about twice as thick, often needing only 3 layers or less to get a tight fit. Also being stiffer due to thickness the pills outer spring dosen’t get in the way and can be left on.