Testing a custom made 16mm Nichia 119 copper core board (non-DTP), edit:sold out

Flintrock · September 29, 2016, 4:41am

[quote=DavidEF]

Edited: I misunderstood. at first. Yeah that's a problem then.

It's not a new idea though (but indeed now I see that this light has no driver):

The original explanation is here:

But in the original they isolated both contacts from the pill. In the first link above it seems only the "hot" (whichever that may be) was connected.

I can see there might be a third option to make the case positive, but it might have issues too, and anyway, it's still a new driver board (and a backward battery).

But it seems copper without DTP can be almost as good as DTP anyway.

djozz · September 29, 2016, 7:51am

You have read a lot around BLF Flintrock, way back into the match days

clemence has had boards made for the new Nichia leds that have a direct connection to the core at the cathode side (where the most heat is produced), and in fact I will be getting some leds to test on his boards. It gives me the opportunity to see how much that differs from my non-DTP boards.

As discussed in the OP, what may be a big factor in how well a non-DTP board sheds the heat is the quality of the dielectric layer. In my 6xXM board test I may have struck a non-DTP board with a good layer while other non-DTP boards may have worse heat-shedding properties.

Gunga · October 22, 2016, 4:07pm

I.might have a buyer for you from cpf.

s1m888 · October 22, 2016, 11:44pm

Hi djozz, I would like to buy some, please check your message.

ohaya · October 23, 2016, 12:07am

Hi,

I’m not clear from your OP where the cutoff is for the $2.8 shipping cost? Is it 19? Or is it 20?

Wherever that cutoff is, can I have that many (either 19 or 20)?

Thanks,
Jim

Jerommel · October 23, 2016, 12:20am

DavidEF:

Flintrock:

So these led’s have no central thermal contact? So a standard DTP style board is not possible? But there’s no reason the ground side of the LED can’t connect straight to the core in a DTP like fashion right? In fact, maybe you can just scrape off the contact and insulator on that side and just try it. Depending on how good the electrical conduction of your thermal paste is (likely not very), might need to do the same with the ground wire then. Anyway, these are clearly a big improvement.

Also there was this thread:https://budgetlightforum.com/t/-/25978  (that should be stickied if it’s not)

Basically it shows similar results to what you have. Copper non-dtp is almost as good as DTP in either copper or aluminum. Was it because of the copper or was it just a better board than the aluminum one? Well now there are two data points. It’s looking like copper probably helps. For those tests, in normal operating ranges (under 3A for that XM-L2) you almost can’t tell a difference between copper non-dtp and dtp and so, probably my idea above won’t make that much difference either.

In DTP though it seems to matter almost none if it’s copper or aluminum.

Well, it would be a lot of work to make a light with the negative side of the LED electrically connected to the board, because the host is grounded to the negative side of the battery, but the driver regulates current to the LED on the negative side. So, you’d then have to either electrically insulate the DTP board from the host, or come up with a driver that regulates power on the positive side of the LED instead. Both of those things have been done before. But in my opinion both of them are more trouble than they’re worth.

Itś a matter of surface area.
Two big surfaces with insulation between them is much better than two small surfaces with insulation between them.

thijsco19 · October 23, 2016, 7:40am

You say that the generic board results in a higher Vf but when you look at the graph the results show the other way around?

DavidEF · October 23, 2016, 8:44pm

yes, you’re right, and in fact, as djozz points out a few posts up:

ECHO · October 25, 2016, 7:03pm

Djozz, I’ll take 5 boards. Check your PM for address and I’ll await your paypal info. Thanks!

Flintrock · October 26, 2016, 3:08pm

Pretty sure it's just slip of the brain/keyboard. djozz is certainly aware that heat reduces Vf in diodes.

djozz · October 26, 2016, 8:13pm

Yes, sorry, I meant ‘lower voltage’ I corrected the OP.
Btw, I read the PM’s, will answer later tonight.

ohaya · October 26, 2016, 8:38pm

Was wondering about that :)…

emarkd · November 20, 2016, 12:31pm

Hey Djozz I’d like 4 of these boards please. Thank you!

snakebite · November 20, 2016, 1:48pm

these should work with that new hex die nichia?
if so these will be a hot commodity.

Texas_Ace · November 20, 2016, 1:50pm

Say what? Got a link?

chouster · November 20, 2016, 2:00pm

here you go. But with 319A, there’s no need for a special board, normal dtp sinkpad or noctigon with for xp footprint.

djozz · November 20, 2016, 2:03pm

They do work and I tested that they work well (though not as good as the VirEnce board), but it requires scraping off some solder mask to widen the solder pads.

Lexel · November 20, 2016, 2:54pm

I take 2 boards to germany

Ronin42 · November 20, 2016, 9:56pm

djozz,

They seem like the work just fine.

But for the slow among us (me included) can you add a list of the LEDs that fit this board to your original post?

and maybe compare to the (what is it?) xp? series noctagon copper bards that we would otherwise need to use.

djozz · November 20, 2016, 11:03pm

A DTP board will always heatsink better than the board from the OP, but only work with leds that have a (neutral) central solder pad.

The OP board fits all leds that have just two solder pads for cathod and anode without central solder pad. And there is not so many leds that fit it that are interesting in flashlights, it is an obscure board!: almost all midpower leds have the two pads but are too dim for flashlights, a series of Nichia UV leds fits this board, Luxeon Z fits it, and with some scraping the Nichia 144A series fits it.