Nichia 119's for cheap (also Cree XLAMP-7090's)

What PCB are you mounting those on? I was going to use RacerR86's method here.

The only vendor I found that sells dedicated 119 boards is Led Mounting Bases

I just use thin copper sheet. It transfers heat well. Just takes a couple minutes after you've done it once:

  • Cut a copper circle that is a little smaller than 16mm. Doesn't need to be precise. Doesn't even need to be a circle.
  • Cut the disk in half and thinly pre-tin the 2 halves where the emitter will make contact.
  • Snip off a small corner of each disk for the emitter wires to come through.
  • Stick the 2 halves on a piece of Kapton tape spaced apart just a little bit.

That's it. Easier than it sounds. The Kapton tape is so thin that it doesn't seem to interfere with heat transfer. There are some flashlights (e.g. the first edition of the TN31) that have Kapton tape under the bases. I don't think it's intentional, but doesn't cause an issue below high currents.

Oh, because the base is so small and in two halves, I tape them down for the reflow. I tape across the 2 halves. The tape holds them from tilting and helps with positioning the emitter. I use thin Kapton tape for that and just cut off the excess afterwords.

Flip the base over and look to make sure the solder didn't bridge the halves. If you have a DMM, test for to make sure there is no short and that the emitter works. Just like you would do with a normal reflow.

EDIT: fixed spelling of Kapton tape.

sweet! I don’t need any right now, but I’m sure I will at some point. Paypal sent :slight_smile:

Thanks for the instructional. I just ordered a bunch of XPG/XPE PCBs from KD since they are so cheap. I'll probably just grind out the center pad but it's good to know other methods are out there too. I'll bet your method allows for better heatsinking.

I just saw a clever idea by Texaspyro in another thread. He said you may just be able to put a piece of Kapton tape over the heatsink pad on the MCPCB. That has to be the easiest way to go.

Check this site out they have some nice LEDs for cheap.

http://www.madscientisthut.com/Shopping/agora.cgi?product=Components&xm=on

I found they also have 110 Lumen 119s for 95 cents each

I soldered a few of these to SinkPads using .001” thick Kapton tape to insulate the thermal pad (I think that with the adhesive it is actually around .0015” thick). I used a .003” thick XPG solder paste stencil (with the thermal pad opening covered with tape). All of them worked fine.

I was a bit concerned that the Kapton tape might push up some and prevent the 3 mil thick solder paste layer from making contact (remember .003” is the thickness of a sheet of paper).

I think that the Kapton tape is a better way of doing it than grinding off the thermal pad… it is fairly heat conductive and does give some thermal coupling to the star… particularly with SInkpad/Noctigon stars with the direct thermal path to the star.

It should also help with regular stars to fill the gap between the thermal pad and the raised LED contact pads. One might even want to use a two or three of layers of tape with those stars.

Copper Sinkpad for 700mA emitter, really texaspyro? :slight_smile: If you have too much moolah, you can always just send them to me, I can help with proper disposal.

I also use Kapton tape + standard XPG base (aluminium - poor man’s copper), it’s just so easy and works really well. No need to bother with grinding. Just tape the top base, cut off to expose +/- section, and reflow. It can’t get any easier than that.

I run these at 700mA (2x7135) without any problem so far. No signs of current leak.

Didn’t have any aluminum ones handy…

Hi,

Can you provide a pic with the tape (before reflowing the emitter, preferably)?

Also, do you think that this (tape method) would reflow ok without stencil (but with solder paste)?

I’m wondering if the solder paste would flow UNDER the tape, onto the middle pad, during the reflow (or melt the tape)?

I think I mentioned that I have some parallel triple stars from IS that I’d like to reflow the emitters onto, but have been dreading trying to grind out the middle pad, so if the reflow works with kapton tape, and without a stencil, that’d be great.

Kapton tape was designed to tape off gold fingers on boards going through wave soldering…

Should work fine when using regular solder… maybe even better than with paste/stencil since you will have a thicker layer of solder.

Packaged arrived in good shape.

Tested a couple last night. I sanded off the middle pad on both 16mm and 8mm boards (thanks RacerR86 for the tip), reflowed with just a soldering iron, and fired them up. Very nice neutral tint! One has already gone into a Nitecore EZAA that previously had an older Cree XRE with a horrible bluish tint. The Nichia is not as bright, but the tint is much better.

Mine arrived today, and boy, they are really tiny!! I haven’t tried yet, but with them being so small, when you cut the Kapton tape, is it like just a “sliver” of tape that you cut and lay down on top of the middle pad on the board?

Cutting a strip of the proper width is a pain. I’ve found it easier to stick a bigger piece of tape on the pad and trim it with a razor. I try to get the width such that it covers half the gap between the thermal pad and LED contacts.

Also, don’t worry much about trimming off any excess length of the strip that sticks out of the edges of the LED.

Here are a few different mounting options I have been playing with. These may or may not be useful to someone:

First up. Dual 119s on X-ml stars. No modifications to the pad required. Can be either in series or parallel— one of each:

The other method is using two pieces of copper tape with a small gap between them, directly mounted to a heatsink. This is a picture of three in series mounted this way around a Chinese 10w, to help improve the color:

Hi,

Thanks!

Sorry to bother you, but can you post a better picture of the parallel configuration on the XM-L star?

Also, did you hand solder the emitters onto the XM-L star pads, or can you reflow them with solder paste?

No bother.

Here is another shot of just the parallel setup (this is currently mounted in my mini-01, although it is producing a small donut hole. I am thinking about reflowing the emitters and trying to raise the two ends with excess solder, to put the emitters on slight angles to each other. Sorry for the digression, we’ll see EDIT: actually I increased the space between the emitters and the reflector and the hole is better. The beam is not perfect, but it is passable now.):

To describe the arrangement: I use a hot plate and solder paste to mount the emitters. The negatives are connected to the outside pads and then the wire pads are shorted together with another wire. The positives are connected to the center thermal pad and the positive driver wire is connected to the small protrusion on the pad.

Let me know if anything is still not clear.

got mine yesterday, thanks tp :slight_smile:

Please put me down for 30 please. Not sure what I will do with them yet but I still have a few Xitanium drivers lying around in my box (outputs 700ma.) I just bought a house so I’m sure I’ll be able to scrap up some fixed lighting things.

Thanks!
AZ

Mine arrived today. :bigsmile: