I bought a 6*7135 convoy from Gearbest once, and it had no thermal compound under the mcpcb. Pull the pill and see if thats the case. I’d be more worried about the one that isn’t heating up as fast.
/\_ +1 Robert
+3
I have the Dessert Tan S2+ with only 3 drivers (7135X3). I purposely ordered it that way, so it would never get too hot to hand-hold, and I could loan it to my wife without concern. Even with only three drivers (approx 344 lumens max) it gets very warm after about ten minutes, just short of too hot to hand-hold.
That’s probably because 7135 drivers are not very efficient when the battery voltage is high. All the “excess voltage” is shed as heat; it’s not used by the LED.
You’d want a light with a boost/buck driver, which is more efficient, and wouldn’t get as hot at the same level of brightness. They’re generally more expensive, though.
One thing I find about the 8x7135 Convoys is that they’re probably more efficient than lights using less chips. All those chips drop the battery voltage a lot, and results in a situation where there is no “excess” voltage. Unfortunately, the side-effect is that the lights are not very well regulated on high.
Well, maybe they’re not as efficient when you consider the entire light. I’m really just talking about waste heat from the driver.
Maybe you could try measuring the tailcap current if you have a multimeter (with fully charged batteries) to check if they are the same at max brightness?
Convoy S2+ on highest mode will produce a lot heat.
I got few unit from different seller.
8×7135 6×7135 normally i use 40% output for cycling light
If you think it gets too hot, you can always remove any 7135. each 7135 is 350mA, so you will loose current, thus less light output, but it will generate less heat as well.
it doesn’t matter if you cant’t desolder properly, if you just break one off, the effect will be the same
I can still hold my 8 chip model after a few min. but much longer after that and it starts getting into ouch territory. After 10 min. Im sure it would burn holes in pockets.
Instead of the thermal compound maybe some thin copper tape would help?
The one that doesn’t heat up as fast will eventually end up hotter though, because with a badly cooled LED the efficiency is lower and afterall the heat has only one way to go: to the flashlight body.
For that to happen it’ll have to exceed some 180°C
Between what and what? 
Adding a layer with a sticky glue backside doesn’t help.
It will be worse than PCB directly on pill.
You can increase the pressure by screwing the pill tighter into the head.
A thin layer of thermal grease will increase the surface contact area.
Not capable of reflowing led’s I ordered a 5050 size Epileds UV led on a 16mm aluminum board for my 8*7135 Convoy S2+. A bit of paste under the board and clean threads on the pill. That’s all. When I heard there was some doubt about the lifespan of this led at 2.8A, I put it up to the test. Being rather wordy I’ll fast-forward to the result. On several occasions I have fired up this light at maximum power, tailstanding on a low table in my livingroom. And left it on, until I got a low voltage warning. It got quite hot at 2.72A … but let’s call it bearable. No smoke, no smell.
Don’t have any scientific data for ya. I was goin on my own experience of the smell coming from my jacket pocket when mine accidentaly came on at turbo for a bit. :person_facepalming:
Sorry i should have been more clear.
Between threads to increase thermal conductivity of the surfaces there.
Tape as in thin strips, not sticky ones. I’ve got some that was left over from high voltage (12kV) termination kits and it doesn’t have adhesives. Just super thin copper. I’ve used it between theaded components before and it seemed to help, didn’t run any tests as i was happy the threads weren’t as sloppy anymore (wasn’t on a flashlight) hence the question mark. I’m new to flashlight modding, so just offering suggestions and personal experience. Keep me lined out friend :+1: 
LOL
That must have been the light beam turning into heat (i guess the pocket inside was a dark fabric?).
Powerful lights can scorch things.
O, i see.
Seems like handy stuff to have around.
Good idea.
Gotcha, the beam is what was scorching my fabric. Good to know how much a pocket can take though, (Dang, 180°C, pockets are tough lol) thanks!!!
Yep black microfleece!!
The copper (I’ll call it ribbon from now on :student: ) is handy. It also makes for pretty aesthetics when glued into the grooves of flashlight cooling fins. As you stated, I figure it hinders the cooling effect, used in that manner, to a small degree though.
Well, the grooves between the cooling fins of the average flashlight are often too narrow to have significant air circulation, especially when they’re deep grooves (or large fins).
It looks nice though.
Cooling blocks like in amplifiers have grooves you can stick your pinky finger in, for example.
About that ribbon, what’s the thickness?
I could use some for enhancing the thermal path between flashlight head and screw in pill.
I can probably find something on AliExpress or Ebay.
I’ve got two types, and comparing them to my feeler gauges one is about .04mm and the other around .08mm.
This is the closest i could find. All the ones i saw have adhesive, so the ribbon i have is probably made to whatever specs the termination kit company wanted. You could probably clean it off before use but the seller claims it is conductive adhesive.
2 pcs/ 5MM X30M Copper foil tape Adhesive copper tape Shield Tape Single Conductive Film COPPER FOIL TAPE Strap
http://s.aliexpress.com/aaAveIr6?fromSns=Copy to Clipboard
(from AliExpress Android)
Nice to know the Convoy S2+ with 7135x8 can withstand continuous max power (~2.8A) until battery drains.
BTW, is that tailstanding test for a stock or modded one?
~
I’ve noted that Convoy (C8 or S2+) with 7135x8 XM-L2 seems to draw around 3.0A (tailcap current with my budget DMM) whereas the one using 7135x8 XP-L Hi seems to draw slightly lower current (2.8A). I wonder if it’s just due to the variance between Convoy flashlights or the XM-L2 is able to draw slightly more current than XP-L Hi? (I’m comparing different Convoy flashlights, not reflow different LEDs to the same flashlight, which I’m not capable of.)
Overall: it was a stock light I bought at GearBest. Just swapped the CW XM-L2 led for the UV led.
Details: put in bigger leads, bypassed springs and made sure everything was dry and clean, except under the led-board.