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

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.

Hot air would work better, probably from underneath to keep from knocking anything out of place. If you could take a suitably small piece of wire formed to mirror the bond wires, give a light coat of paste, get it positioned and then add heat...

Can you show a pic with your resistor mod?
Did you use a Trim-pot?

djozz sorry about the OT.

Added one R120 for about 4,7.
Two R120 in series (on top of the stock resistor) was about 3,65 I think. Stock output on mine was quite close to 2,8 I think…

Its basically the same driver that I modded in this messy thread. But there are a few differences. If you have the same looking driver, yours might have differences too. I have not tested it for more than a short period though, so mod at your own risk… :wink:

Edit: I have no intention of using the huge stock aluminium mcpcb in that light. Ill kinda make a cooper “pill” for a copper mcpcb to sit on… Ill might make a mod thread some time in the future…

I'm seeing consistent issues with not being able to get 3.5A+ out of an XP-G2/SinkPAD combo, whenre I can with an XM-L2, in a single cell Nanjg driver. I think you're right - XP-G2's have a higher Vf demand.

What is the amp tailcap measurement? I've been unable to get above 3.3-3.4A I believe. It still does well and bright, but just not getting the full amps.

Basically the same as with me and others… XP-G2 seem to need two cells (and a buck driver) in order to go higher…

That's perfectly alright, I am guilty of that myself all the time.

fair play for trying :slight_smile: I’d suggest some enameled copper wire to replace the bond wires, but making suggestions is easy when you’re not doing the work!

I wonder if dedoming with gasoline weakens the wires. I know gasoline weakens some metals. I learned the hard way when I soaked a motorcycle chain in gasoline to clean it.

Or maybe the dome just physically supports the wire and helps prevent it from sagging and shorting at a lower amperage.