P60 Copper Wrapping Measurements

Greetings all.

After reading a lot of threads about wrapping P60 drop-ins with aluminum/copper foil, copper tape, soda can strips or copper sheet strips, I decided to purchase a sheet of 3mil copper sheet from Ebay and do some wrapping of my own. I also decided to measure the difference in temperatures to see what all the hype is about.

The ingredients:

- Solarforce L2P

- XM-L T6 drop-in with 3.5A (10x7135) 105c Nanjg driver

- 2 x fully charged Trustfire Flames 2400mah

- Pure copper sheet 3mil thick

- Digital thermometer

Unwrapped Measurements:

- Solarforce L2P with normal unwrapped drop-in

- Trustfire Flame battery measuring 4.16v

The resting temperature of the light was 24.9'C:

I left the light running on High (3.5A) for 20 minutes and took measurements every minute for the first 10 minutes, and then at 12, 15 and 20 minutes.

After the 20 minutes the battery measured 3.88v

Wrapped Measurements:

I took the whole light apart and left it for an hour to cool down to 24.9'C again while I wrapped the drop-in with the copper sheet.

I used a fresh Trustfire Flame which measured 4.15v

About 6" of copper sheet and the drop-in fits really snug in the L2P host:

Breaking the 50'C barrier

After 20 minutes the light was so warm, I had to go get oven gloves to pick it up and take it apart so that it could cool down. The battery measured 3.92v

Results:

And here are the results:

I think it is fair to say that the copper sheet acts as a very good heat transfer medium from the LED to the P60 Host.

Thanx for watching. Any inputs/comments welcome!

EDIT: Fixed Pictures. See the following threads for good results too: https://budgetlightforum.com/t/-/23586 and https://budgetlightforum.com/t/-/23793

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!

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.

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.

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.

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?

There is no adhesive.

Here is the link: http://www.ebay.com/itm/COPPER-Sheet-Metal-Tooling-Foil-6-x9-x-003-40gauge-3mil-axvz-ART-CRAFT-SUPPLIES-/251026170631?_trksid=p4340.m444&_trkparms=algo%3DCRX%26its%3DC%252BS%26itu%3DSI%252BUA%252BLM%252BLA%26otn%3D5%26ps%3D63%26clkid%3D7294825512160175106

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

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

Many thanks.

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

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.

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

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

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.

I am looking to wrap your drop in so that I can get the best heat transfer and use it on Turbo for extended periods, lol.