6x 20mm XML-ledboard comparison

Wow! Thanx for these tests djozz! :slight_smile:

I’ve been planning on drilling a 2.5mm hole through the dielectric layers of my cheap copper MCPCBs for XM-L and fill the hole with an AWG 10 copper wire. I tried it with my hand drill before but I just can’t bore trough. I’ve contacted a friend who has a drill press and we’ve scheduled the boring after the Holy Week. Based on your tests, these cheap copper MCPCBs should be just like (almost?) SinkPads or Noctigons. :bigsmile:

Thanks. Your efforts are really appreciated!

Awesome findings…proof positive that the direct heat path to the star does actually increase the heat transfer resulting in less heat sag and more light…and it doesn’t matter how that direct heat path is made, whether it be by sinkpad pressing up the center or cutting out the dielectric from a cheap pad and filling with solder

Great post man…great findings!

How long did you let the light run before you took your readings? Did you do a first on, then 30 second later test once things got nice and warm…just to compare what happens when the heat builds up

This test along with a thermal test of the emitter to see how hot it is would be a good identifier of which is better at moving the heat away from the emitter

Either way…AWESOME test man!

And would you say spending the extra $.75 for an actual sinkpad over the cheap dielectric covered FT copper star is worth it rather than doing all that surgery?

very cool sry, hot tests you did!

Very relevant question of course. Each test started at 0.5A, 10 seconds wait, voltage and output reading was written down, current was turn up to 1A, 10seconds wait, etc. up to 7 amps or max output. So the power went up gradually during the test. I monitored the luxmeter of course, and found that nowhere during the tests the readings were fast declining, when waiting longer before taking the reading the number only very slowly went down. This test with so many numbers could not have been done with after each new current waiting everything to settle to the max, instead I waited for the same 10 seconds each time, and I think it gave a good enough number that did not alter very much over time.

Yeah, appears that way, so by the time it got to 3A it had already been “cooking” for a bit, even longer at higher currents…so the heat sag wouldn’t be an issue with the readings…nice!

So do you think it’s cost effective to get sinkpad over the cheap FT copper stars and cut out the dielectric layer, or just too much hassle

Thanks for the test. This is very good information. Much more useful than I thought it would be thanks to those additional boards you tested. Now I wonder why the copper board with the dielectric layer performed so well.

Exactly, that is what I wonder as well: the minor difference between the aluminium and copper Sinkpads suggest that the board material is not critical -the bottleneck is closer to the led-, but when a dielectric layer is present, copper and aluminium are miles apart, makes no sense . Perhaps the dielectric layer in the copper board has a lower thermal resistance as the dielectric layer in the aluminium board? I scraped that layer in the copper board away: it was not exactly a thin layer, much thicker than I expected actually.

Subbed. Thanks for the review!

Amazing job djozz and thanks for all the effort! You helped me a lot with your charts and tests and I’m sure lot of other people share my thankfulness.

Super tester! Thank you for these tests. That is just so useful and revealing. Thank you thank you thank you :-)

Thank you so much djozz. This is a great effort. The only issue is that you misspelled “.” with “,” on your notes all the way.

Sorry can’t help myself. Just kidding. :slight_smile:

I am actually quite surprised to see copper+dielectric is handling its own up till higher amps. I have a bunch of them from Aliexpress and am still thinking of the best method to punch through to copper layer. And then…

Seems to fit my style. How deep did you need to dig/punch? Got any pics?

The aluminum SinkPads turned out to perform well. Would ordinary aluminum MCPCBs perform the same when its dielectric will be removed just like the copper MCPCBs? :~

Probably…

Copper hype… :slight_smile:

And compliments to Djozz for this interesting topic.

Pulsar13 wrote:

Seems to fit my style. How deep did you need to dig/punch? Got any pics?

Deeper than you would think. Those combined layers are thicker than I imagined. It may also be that I am compressing the underlying copper, but I try not to do that. Not sure if I have any lose ones around. If I do, gouge it and post a pic in the next day or two.

I have no idea how it performs. I'm guessing somewhere between the djoss' number 3 and 4 bases.

The problem is, how are you going to solder the LED to the bare aluminum?

Thanks DJozz! Though I think you might have your #’s wrong in the first picture. IIRC, the one with the tc cutout in the dielectric layer is the SinkPad 2. Backed up by the fact that the XM-L2 is of course a newer LED than the XM-L, it would seem odd to me for the “newer” SinkPad 2 (that you have listed as 5) to ignore the XM-L2, while the “older” SinkPad 1 would have it listed on the layer. I’ll pull apart my SupFire M6 to check—I need to lap those puppies anyway.

EDIT: Not really necessary, if you zoom in on the photo, the one you have labeled as 4 has SinkPad II written on the bottom, but listed as SinkPad V1 in the key, and the one you have label as 5 has SinkPad written on the bottom, but is listed as SinkPad V2 in the key.

Not a huge deal though :slight_smile:

You are completely correct, I mixed the two alu Sinkpads up in the first picture, luckily just in that picture, not in the tests themselves :-)

I will make a note in the OP.

WOW. Djozz. Once again, FANTASTIC work!

Very useful information to have.

Thank you!

Yeah I’ve been asking myself that same question too. :~

So I think I’ll do the same thing to aluminum MCPCBs what I’ll be doing to my copper MCPCBs - drill a 2.5 mm hole at the dielectric area then fill the hole with copper from an AWG 10 wire which is about 2.58 mm thick. That should do the trick (I hope). :slight_smile: