Whats up with this XP-G2 with black base and only able to pull 1.8A DD

A while ago I got a few bare XP-G2's from a trusted source, they all came in their tape packaging, I bought 3 at that time, but all cut apart individually.

The first 2 I used right away had the normal green base (silver on top, green on bottom), this third one I finally had a need for today so I opened it up and reflowed it to a noctigon and was only able to get 1.8A testing it straight to a battery. I even tried using a 5V source and can not get it up over 1.8A at all. I took it back off the board thinking I had a bad solder joint (or no connection on the center thermal pad) and I found this. The one with green base is one of the other two I removed after finding this to check it, I unfortunately damaged the dome picking it up with tweezers (I can probably dedome it and still use it), both it and the other good one(now in a customer's light and returned to them) had no issues pulling over 4A each, its only this one that wont. Other than the now damaged dome they look exactly identical on top, even under magnification, the only difference is the color of the base.

Just wonder WTF is going on with this one, why its different and why it wont pull the normal current.

All 3 were supposed to be S2 2B.

Top picture, the bad one is on the left in this pic (the good one with green base is the one with the damaged dome on the right)

In this shot the good one (the green one) is the one of the left (sorry for getting them mixed up)

Yes that’s why I said “I don’t want to assume” and also why I didn’t put “possibly fake” as the thread title. I’m not trying to state it’s fake or counterfeit, especially coming fromwhere they did, but something is definitely “off” with it. It doesn’t perform even to 50% of what a “normal” XP-G2 S2 2B does and it physically looks different. In fact I’ve never seen any gen 2 ANY cree with anything other than green there.

Wow, possibly connected to the esd/zener diode thingy like with the XPL?

weird! I hope it is not the newest batch and that the Vf went way up, like seems to be going on with the XM-L2.... :-(

Please, No! :( :( :weary:

Cree, don’t do this to us! We love you!

I doubt that, I got this a few months ago, I don’t use XP-G2’s much. Probably around early summer.

Ok I get what you’re saying, its not counterfit, but SOMETHING is wrong with it / different about it, let’s focus on what/why.

edit: I’m not looking for a fight man, sorry, statement redacted. I just have an especially low tolerance for bickering / nitpicking this time of year…

Here’s a better pic for you, the green isnt just on the bottom, it’s the side’s too.

left is like any other emitter I’ve ever seen, right is this one the OP is about

Also it cant be a simple higher vF issue cause I tried all the way up to 5V, if that STILL wasnt high enough to cover a slight increase (like we saw in the newest emitters) then this couldnt even be considered a 3V emitter any more.

Something is up with this emitter, its not the same as a regular XP-G2, its completely untouched as far as the ESD diode (the dome is still perfectly intact), something is up with this emitter…

First time I seen a Black, maybe something happened to the thermal path and the green plastic got burned… can you scrape it a little with a needle or file to see if it is all black or there is green underneath?

Interesting and disturbing if Cree is deciding to control by any means how much current passes thru their leds

Maybe explain your testing a little more. You put 5v directly on the emitter?

I scraped as much as I could without breaking it with the point if a diamond needle point file (even tho it’s not usable I’d like to keep it intact so I dont want to use to much force / to aggressive of a tool) and I never got threw the black. Not sure how deep I really got tho, isnt it ceramic? Seemed pretty resilient to the diamond file.

@ wight
my testing method was using a voltage & current adjustable AC-DC constant current converter my uncle built me (I simply just dont understand all the components in that thing to better explain it, he’s way smarter than I am, he’s a EE’ing professor at BGSU) but it has a max output voltage I set (under zero load) and then it supplies 1-3A out (also selectable, both parameter’s are set by a pair of POT’s) at whatever voltage the load need’s up to the set limit. With the way I had it set it could of drawn any voltage it needed up to 5V and any current it needed up to 3A, even at those settings it was still only doing the 1.8A (didnt have a second DMM connected during the test to see instantaneous vF it was pulling but this test SHOULD have eliminated a slight increase in vF being the culprit of the low current draw, since it had available to it up to 5v should it have wanted it)

edit: I think a more simple way to describe the unit would be an AC-DC selectable constant current analog power supply, like I said it’s a piece of equipment I rarely dig out and dont really understand…

Does cree have a customer service email? Maybe you could inquire about it with them and see what they say

Found their contact page here


Not sure who the right contact should be


Or this

I didn’t see a place to send an attachment so maybe insert a link to the picture or the forum…

You’re right, it is ceramic. I forgot that myself. :wink:

I understand what you are describing.

Do you know what voltage was required to achieve 1.5A?

I don’t have any good ideas about what’s going on.

Good idea, on the bottom of that page there was a direct email: productsupport@cree.com, I’ll see if I get an answer, I figure probably not till next week, cause of the holiday, at the earliest.

Cereal_killer, did you ever get a response from Cree?