Crash-testing a XM-L2 and a XP-G2 on copper Sinkpads

holy cow.

Yes.

Tonight I stuck an XPG2 neutral on a Noctigon inside a Sipik 68. I replaced the driver with a Nanjg 105c with 3 extra regulator chips attached for 4 amps total, running on IMR 14500.

It’s bright, but unfortunately, the focal length is wrong for the new star. I’ll need to file down part of the outside of the pill in order to make it focus properly.

As said, the volt reading of the power supply is a bit wacky, in the video it is too low for a while when the actual voltage is higher, then suddenly starts displaying a correct voltage for the rest of the experiment.

Whoops, sorry missed that part. :slight_smile:

Nice. Thanks for sharing. Looking forward to graphs…
I killed an XP-G2 yesteday. Mounted on 20mm Sinkpad attached to a large piece of aluminium. It was de-domed. About 5A and it was dead. Instant kill… :stuck_out_tongue: (no worries only a cheapo CW from FT)
Im pretty sure others have used them at that current. Id guess my de-doming job had weakened one or both wires (a bit strange since I don’t touch them and never had issues with de-doming in the past).

I have a driver (from STL- V6) that I can easily resistor mod from about 2,8-5A as I wish… Modded it to 4,7A yesterday, but did not to dare try it on an XP-G2 after I had fried one at 5A with another driver. Dialed it down to 3,7A just to keep it moderate. 0:) Im already feeling inspired to go higher now… J)

Do you think emitters are killed more easily if they go from cold to instant high amps? Im a bit surprised they managed all those amps, especially the XP-G2.

Do you feel like doing MT-G2 if you get some funding from several members?
Ill donate 2,5 bucks for the sake of science (killing and MT-G2 and getting some numbers out of the process). Im sure some other members would contribute too.
Or maybe just contact Hank (IOS) and see if he is feeling generous. 0:) Worth a shot…

What do you mean by cold? 20-25C (room temp) or 0C. You want to thermally shock the LED?

Room temperature…

I wonder how an LED like the Luxeon T would perform on a Sinkpad board.

I'd love to see the Luxeon T for sale on a Sinkpad, it seems excellent for flashlight use and I understand it has very low internal thermal resistance. It is just that it has a very different solder pattern and needs its own Sinkpad.

I have been thinking about it, but apart from the costs I only have one at the moment and I have other plans with it. Maybe later.. (or someone else )

I would like to see an MT-G2 being fried too:) and would like to donate some money toward the emitter as well.

They don't pop or even turn blue at 9 amps, though based on my one sample I can't say it puts out more light at that much current.

hmm…. they don’t have a max current that ultimately kills them?

Almost certainly, but I was using an actual driver in a light with normal batteries. I don't know of a driver that does more than 9A and I don't have a big power supply to drive it directly (I have a few, but they're all in the range of 11-16v).

Ok, I tried to repair the broken bond wires and it was a complete failure. But what is better than looking at other peoples failures ? So here we go, enjoy!:

The leds with most of the domes removed (left xm-l2, right xp-g2, same magnification), still in the Coleman to see through the silicone well. You can clearly see the incinerated bond wires (strangely they go two at a time )

I cleared away more silicone from the xp-g2 and also the bond wire debris and bended the bare wire ends are close to each other, added some solder paste and touched it with the iron. The solder paste melted and got immediately sucked away by the iron, no connection .

Added more solder paste, same thing, and also destroyed the wires. Went over to the xm-l2 led, with loads of solder paste.

Failed miserably again, destroyed the wires again, now I cleared all the debris and tried to solder what was left of the connections with big blobs of solder wire:

Actually when connected to a led tester I got some very faint light, so I tried soldering again for a better connection. Well, it ended with nothing at all, end result: dead and ugly looking led:

Ah, I see what you mean, thanks for the explanation.

djozz, awesome work and nice try repairing the wires. :slight_smile:

Do you think a dedomed LED will handle less current?

comfychair, are you using this 9A driver?
Does it give output 9A to an MT-G2 on high?

You do have a point though. If if there are no other drivers out there that can handle 9+ out there it is a bit limited use in knowing. But its always nice knowing how much “head-room” you might have. J)

Nice attempt djozz. At least you tried, which is more than I have though of in the past and with my recently fried XP-G2. :slight_smile:

There are two planes on the substrate, the die is sitting on the negative plane & the bond wires jump over the little isolation trench to make the positive connection. Looks like the solder bridged across the trench. Did it act like there was a dead short, or just total open ckt?

I think the way to do it would be to try and stick a wire to the connection points on the die first, then lay them over and tie in to the + plane. The issue you'll run into trying to do it with solder is that with such small tolerances enough heat to melt solder at one end will also melt it at the other at the same time and the whole thing falls apart.

Yes and yes. https://budgetlightforum.com/t/-/18955#comment-411218

Ah, never knew that the two wires are parallel, thought that current was going from one to the other, that explaines easy why they both go.

Perhaps an idea is to start with a functioning led and 'enforce' the bond wires with solder blobs.