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

No hurry, haven’t sold any yet. I realise now that I even have not sent Gunga’s boards (sorry Gunga :blush: ) , at least he did not sound like he needs them right now :person_facepalming:

I’m supposed to get the new Nichia’s from clemence, but via maukka who is going to do a tint/CRI test first.

Sounds good!

Whoops! Yeah. I forgot about them. :slight_smile:

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 (maybe one percent?) 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.


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.

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

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.

I.might have a buyer for you from cpf.

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


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)?


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

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?

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

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

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

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

Was wondering about that :)…

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

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

Say what? Got a link?