Okay, wait. You’re saying that thermal paste, something that is supposedly made for helping to conduct heat between two surfaces, is just barely better at conducting heat than air? That is hard for me to understand. According to Engineering Toolbox, even Styrofoam (made to NOT conduct heat) conducts heat better than air. Plain ole Epoxy has a thermal conductivity that is almost 15 times that of air. Insulating brick (didn’t know that existed) conducts heat at a rate 6.25 times that of air. Yes, these are still relatively tiny amounts, because the only thing that air conducts heat better than is a vacuum. But, we’re talking about thermal paste. It should be pretty good, I’d think, at doing what it was made for - especially compared to leaving the air void that would be there if the paste wasn’t!
edit: to clarify, there are several gases on the list that are less heat conductive than the air we breathe, but I call them all ‘air’ for the purpose of these comparisons.
David, for me it’s a moot point…2 bare pieces of metal in contact with each other will conduct heat between each other. period. Are there microscopic gaps that hold air at the junction? Most assuredly. It becomes a matter of quantity I would think. Microscopic air gaps between surface contact leave how much percentage of contact at a loss? Can’t be much, if the gaps are microscopic in nature, right?
It’s really a question of efficiency, and the effort to increase efficiency might be more than the net gain in these applications. We struggle to max out the emitter performance, while the cell sags and loses power…effectively killing all of our efforts in the first half minute anyway. Vicious circles.
The bigger point is that if the thermal paste is not applied as it was intended then it could be more detrimental than beneficial. The idea is to fill the air gaps and leave the metal to metal contact. By using too much, you separate the metal to metal and only have paste…losing more than you gain.
I saw someone recommend applying the paste to each surface and then scraping the surface clean of paste with a razor blade. The two surfaces would then mate with the best possible contact.
Almost all of these considerations are extreme examples of taking things to the Nth degree. Something we’re getting pretty good at in our search for flashlight Nirvana.
Yes, that's exactly what I'm saying. Your ideal insulator, styrofoam, could very well be a very good conductor at a thickness of 1-3 microns.
edit: And this is why these reference charts are misleading at best. You have to know how to interpret the data as it applies to a specific situation, and if you don't know how to do that, you'll think you understand something you really don't.
i just built one of these lights and i get 6.2a with a blf17dd and sony vtc5. does anyone else get more?? i would like 10a. lol maybe il try changing the standard wires to 18 gauge.
You don't need 18 AWG wires, the 22 AWG are just fine for 9A-10A. What is your current measuring setup? If you are using multimeter probes then you have a huge problem right there.
Hahahahaha oh Richard… Where is that FAQ you were talking about?
As rmm alluded to, the problem is in the meter leads you are using. If you measure the 6 amps, and then touch the leads together circumventing the multimeter, and the light gets brighter, there’s your other 4 amps.
question-i will do my own tripple xpl.will be a big difference,if i will use IMR or Unprotected 18650? in the output of lumens…or is it the same? i use original branded ones…
