Somehow fried the LED in my Klarus XT2CR Pro.

[Monocrom]

So last night at work, took out my XT2CR Pro to check something.
Quick blast on Turbo for a few seconds. All good! Or so I thought....
Bezel seemed suspiciously hot. Thought nothing of it at first.
Quick blast never an issue before. Had the light a handful of years.
Awhile later used it on Turbo again. Why is there a donut in the beam?
Turn the light off, take a look; and the LED is burned out! Black as Midnight!
Light still works. But that bezel should be warm after a few seconds on Turbo.
Nope! It's blazing hot! Something horribly wrong. Not taking any chances!
Disposed of both the light and the battery inside (properly) soon after work.

This Klarus model has been completely trouble-free up until last night.
Checked Battery Junction to confirm my suspicions. Found what I needed.
On Battery Junction, underneath the description for this light is the following:

....features intelligent temperature technology, and will automatically adjust the brightness output to prevent overheating and damage to your flashlight and batteries.

Yeah........ Seems that technology decided to fail miserably for no reason at all.
Didn't drop the light. Never abused it. Never got it wet. NOTHING!
Just out of the blue one night it quit working. Lost one of my favorite lights.
Love the U.I. and the subtle crenulated bezel. Could buy another one. But why?
Lost confidence in it, and Klarus. Even worse, I have a more powerful Klarus
(XT21X Pro). Is this what's waiting for me down the road again, with that one?
I have several other less power Klarus models too. Yeah, I'm done with Klarus.
Going to replace my XT2CR Pro with something else. From a different brand.

 

[IMA SOL MAN]

LED's do have a finite lifespan. How many hours do you estimate you had on the LED?

 

[LRJ88]

So last night at work, took out my XT2CR Pro to check something.
Quick blast on Turbo for a few seconds. All good! Or so I thought....
Bezel seemed suspiciously hot. Thought nothing of it at first.
Quick blast never an issue before. Had the light a handful of years.
Awhile later used it on Turbo again. Why is there a donut in the beam?
Turn the light off, take a look; and the LED is burned out! Black as Midnight!
Light still works. But that bezel should be warm after a few seconds on Turbo.
Nope! It's blazing hot! Something horribly wrong. Not taking any chances!
Disposed of both the light and the battery inside (properly) soon after work.

This Klarus model has been completely trouble-free up until last night.
Checked Battery Junction to confirm my suspicions. Found what I needed.
On Battery Junction, underneath the description for this light is the following:

....features intelligent temperature technology, and will automatically adjust the brightness output to prevent overheating and damage to your flashlight and batteries.

Yeah........ Seems that technology decided to fail miserably for no reason at all.
Didn't drop the light. Never abused it. Never got it wet. NOTHING!
Just out of the blue one night it quit working. Lost one of my favorite lights.
Love the U.I. and the subtle crenulated bezel. Could buy another one. But why?
Lost confidence in it, and Klarus. Even worse, I have a more powerful Klarus
(XT21X Pro). Is this what's waiting for me down the road again, with that one?
I have several other less power Klarus models too. Yeah, I'm done with Klarus.
Going to replace my XT2CR Pro with something else. From a different brand.

Do you have a picture of the LED? It doesn't sound as thermal regulation as much as the die getting way more current than it should, the driver letting through more than usual.

 

[rwolfenstein]

I think this the reason I am not for all the lumens. It gets too hot, there typically isn't a good heat sink and the led burns out.

 

[louie]

I don't know the light, but if I feel anything can break and if I like the features, I'd just get another. Looks like a 5 year warranty, maybe you're covered?

After a quick look at the specs, it says it has one Cree XHP35HD. I don't know how they get 2100 lumens out of it, as the Cree sheet says the XHP35.2 is typically rated for 400 lumens at 350mA and 300% (I assume 1200 lumens) of that at 1500mA, which is the max rating by Cree. It sounds like it's operating way out of spec in turbo and I'm not surprised some burn up, regardless of thermal sensing.

 

[KITROBASKIN]

Glad you had a backup!

 

[Monocrom]

LED's do have a finite lifespan. How many hours do you estimate you had on the LED?

Not even a tiny fraction of its lifespan was used up.

 

[Monocrom]

I don't know the light, but if I feel anything can break and if I like the features, I'd just get another. Looks like a 5 year warranty, maybe you're covered?

After a quick look at the specs, it says it has one Cree XHP35HD. I don't know how they get 2100 lumens out of it, as the Cree sheet says the XHP35.2 is typically rated for 400 lumens at 350mA and 300% (I assume 1200 lumens) of that at 1500mA, which is the max rating by Cree. It sounds like it's operating way out of spec in turbo and I'm not surprised some burn up, regardless of thermal sensing.

Well, wasn't aware of that. Even taking into account rated lumens vs. Out The Front numbers, clearly Klarus was irresponsibly overtaxing the LED. Whatever "thermal protection technology" they have in it is likely just marketing garbage. Unfortunately for me, it has been over 5 years. Now I'm stuck with a bunch of Klarus lights. One more powerful than the one that burned out. Thankfully most of the others can be run on ordinary CR123s, AAs, or AAAs. So, that's what I'll do with them.

As far as the XT21X Pro goes.... I'll just use it. If it burns out too, I'll chuck it. It's practically brand new. I could sell it, but I know now that it's basically junk just waiting to malfunction. Having morals, I just can't pass the issue onto someone else. Thanks for the info. regarding what that particular LED is supposed to produce, when it's not being horribly abused.

 

[rwolfenstein]

I started using a Olight Warrior X3 at work, but I keep a streamlight stinger as a back up. I figure with how hot it gets and from as many lumens it puts out, it would burn itself out. Its why you always keep a back up.

 

[Monocrom]

Yup. Grabbed my back-up when the Klarus burned out. Got a couple more a few yards away in my car too.

 

[Stress_Test]

If the Turbo mode is reasonably "hidden", maybe you could still use the light but just avoid the Turbo mode? On any of these lights that have a Turbo mode like that, I'd be leery of using it for more than just a brief burst. Relying on the software and/or electronics to avoid a meltdown seems like a bad idea to me.

I wonder if maybe the thermistor, or whatever is used for feedback, failed in the light and so it never tried to throttle back.

 

[rwolfenstein]

Yup. Grabbed my back-up when the Klarus burned out. Got a couple more a few yards away in my car too.

I dont know enough about Klarus, but I have used a jetbeam a lot and its held up on turbo.

 

[Monocrom]

If the Turbo mode is reasonably "hidden", maybe you could still use the light but just avoid the Turbo mode? On any of these lights that have a Turbo mode like that, I'd be leery of using it for more than just a brief burst. Relying on the software and/or electronics to avoid a meltdown seems like a bad idea to me.

I wonder if maybe the thermistor, or whatever is used for feedback, failed in the light and so it never tried to throttle back.

Main tailcap switch takes you straight to Turbo. There is a ramp "button" underneath the tailcap switch that can take you to lower settings. It's the main thing I loved about the light. That ramp was out of the way completely unless you intentionally wanted to hit it. And yeah, only used it on short bursts when it came to Turbo mode. Maybe 3 seconds at most. Like I said, never an issue until that night.

I just thought that my short usage on Turbo is why the thermal protection never kicked in. Now I'm starting to think that there was no protection built into the light. Just marketing BS. I mean, even with the donut in the beam, output was still impressive. It still worked. But the head heated up just WAY too fast. Had to stop. Cut my losses before it started smoking or even worse, venting with flame. Maybe it never would have. But not taking that chance.

 

[PhotonWrangler]

So last night at work, took out my XT2CR Pro to check something.
Quick blast on Turbo for a few seconds. All good! Or so I thought....
Bezel seemed suspiciously hot. Thought nothing of it at first.
Quick blast never an issue before. Had the light a handful of years.
Awhile later used it on Turbo again. Why is there a donut in the beam?
Turn the light off, take a look; and the LED is burned out! Black as Midnight!
Light still works. But that bezel should be warm after a few seconds on Turbo.
Nope! It's blazing hot! Something horribly wrong. Not taking any chances!
Disposed of both the light and the battery inside (properly) soon after work.

This Klarus model has been completely trouble-free up until last night.
Checked Battery Junction to confirm my suspicions. Found what I needed.
On Battery Junction, underneath the description for this light is the following:

....features intelligent temperature technology, and will automatically adjust the brightness output to prevent overheating and damage to your flashlight and batteries.

Yeah........ Seems that technology decided to fail miserably for no reason at all.
Didn't drop the light. Never abused it. Never got it wet. NOTHING!
Just out of the blue one night it quit working. Lost one of my favorite lights.
Love the U.I. and the subtle crenulated bezel. Could buy another one. But why?
Lost confidence in it, and Klarus. Even worse, I have a more powerful Klarus
(XT21X Pro). Is this what's waiting for me down the road again, with that one?
I have several other less power Klarus models too. Yeah, I'm done with Klarus.
Going to replace my XT2CR Pro with something else. From a different brand.

Dang. I'm sorry to hear this! My first suspect would be the driver circuit. LEDs generally don't go into thermal runaway by themselves. I'm betting an inspection of the driver board would reveal a visibly cooked IC or current limiting resistor.

 

[Monocrom]

You might be right. I just couldn't take any chances. Both the light and battery are gone.

 

[M@elstrom]

I dont know enough about Klarus, but I have used a jetbeam a lot and its held up on turbo.

I have used a Klarus XT11 (800lm model) as my primary duty light since 2011 without an issue, it's been dropped more times than I would like (thanks to a poor holster design) but remains 100% reliable, for me Jetbeam has been a different story...

Jetbeam CL/E (twisty) suffered body thread issues
Jetbeam Jet-3M suffered a fatal tailcap failure (but was a great light up to this point)
Jetbeam RRT-15 died and returned with low output (limp mode)

My backup light is an incandescent Streamlight Scorpion (Strion bulb + 17670)


Two is one, one is none 👍

 

[Monocrom]

Looks like I should have bought an X11, instead.

 

[Monocrom]

Replaced my Klarus with a similar light.
AceBeam Defender P16 Limited Edition O.D. green,
collab with Maratac.
Main thing is the U.I.
Extremely similar dual-button tailcap set-up.
Also 18650, with bezel-down carry-clip.
Bezel scallops are less aggressive. (I can live with that.)
Rated lumens 1800 instead of 2100. But it's rated lumens.
The AceBeam has a wider buy more concentrated hot-spot.
(If that makes any sense.)

Have had good luck with AceBeam's lights in the not-too-distant past.
Though really wish SureFire would adapt this U.I. set-up.

 

[IMA SOL MAN]

I don't understand putting crennalation on a light with a pocket clip, obviously intended for pocket carry. Don't the designers realize it is uncomfortable at the least, and dangerous at the most?

 

[Monocrom]

I don't understand putting crennalation on a light with a pocket clip, obviously intended for pocket carry. Don't the designers realize it is uncomfortable at the least, and dangerous at the most?

I agree with you. But the ones on my Klarus XT2CR Pro were extremely shallow and mostly flat. Being bezel-down carry in the pocket, I never actually touched them when reaching for the light. Never once dug into my thigh. Klarus definitely did the scallops on that light, properly. Ironically, the ones on my AceBeam look somewhat more aggressive than on the Klarus. But in reality they're less aggressive. I like having a hammer-fist enhancer on the end of my light. Just in case I need to use it in a sudden self-defense setting. But thankfully that type of bezel on both models is out of the way when I don't need it.

EDCed the AceBeam last night at work. No issues with the bezel being uncomfortable in my pants pocket while sitting.