I Just (slightly) Cooked a Quark (point of interest for Jason and 4-7s team maybe?)

[Stress_Test]

Don't know if the Prometheus / FourSevens team have done any destructive testing or test-to-failure of Quarks before, but I came close to running such a test by accident!

I've got an old 123^2 (9 volt) Quark with the warm / hi-cri emitter. I was using it with a 16650 just now to provide some bounce lighting while fooling around with my camera.

I had it on "turbo" (head tightened) and propped on a desk; not tail standing but the head was sticking up and not touching anything.

It was hot in the room (low 80s) since it was upstairs and it wasn't air-conditioned, but ambient temp shouldn't have really been an "unusual" case, because heck, often in the summer time, it'll still be 80 degrees F at 9pm!

I don't know exactly how long the light was sitting there on turbo. Maybe 10 or 15 minutes total? I was engrossed with the camera and didn't think about the light for a while until it suddenly hit me, "oh, I should turn that thing down"

I picked it up and it was HOT. Not too hot to hold, but unpleasantly hot. I turned it off, took the head off and the battery out so everything could cool down. It didn't take long to get back to ambient temp. I checked the battery to make sure nothing was abnormal and it showed about 3.9 volts, so no problems there.

I turned the light on again and didn't see any obvious issues such as tint shift. However, as I looked at the reflector, I noticed that one area close to the LED showed some discoloration, kind of like when steel has been welded and gets some wavy color.

On close inspection of the LED (as well as I could see with my eyes anyway) it looks like there's some charring or melting at the edge of the dome. I think the reflector may just be showing the LED flaw. I wouldn't think the aluminum reflector could've absorbed enough heat to discolor, but I don't have much experience in that arena.

No obvious defects in the beam color or profile. The hotspot is just slightly elongated / oblong a little bit, but it's not really noticeable unless shining on a blank wall, and even then I had to rotate the light back and forth to really notice it. Yay for orange-peel reflectors, right? I've seen worse beam patterns from lights brand-new from the box.

Anyway, I thought this might be interesting to share from a technical standpoint. Most of us know in general that you don't want to leave a small, high-powered light sitting by itself on max for very long, but I've never before done it long enough to cause noticeable damage.

In another thread I was reading recently, regarding a 6xAA light, a member was flabbergasted as to why such a large light was used to generate "only" 700 lumens. Well, this proves that larger lights also have an advantage when it comes to heat dissipation.

For instance, I've got a triple-emitter, 6xAA Energizer light that has a max of 1200-ish lumens on high, and something like 200 to 250 on low. Just a few days ago, I ran that light for hours on the 200 lumen setting and it just barely got warmer than ambient, almost unnoticeable. Whereas the small Quark at 200 lumens started to cook itself after only 15 minutes or so. Sometimes larger lights do have an advantage!

I'll definitely be more mindful of using the full-power mode on my Quarks from now on.

I'll try to get some photos of the slightly-toasted emitter. I don't have an actual macro lens for the camera though, so I don't know if the burned area will show up or not.

 

[3_gun]

A trick for close ups w/o a close up lens or setting ; with good lighting (flash doesn't count) back up a few feet and zoom in, you'll need really good lighting, a steady hand or a tripod but it can workout just fine. Helps if you can set the focus area to a centered single point too.

 

[Stress_Test]

Alright this was about as clear as I could get with what I have at home. If I take this light into work and get my hands on the macro lens and camera there, I can probably get closer detail on the LED die itself.

This shows the slight red/orange/green discoloration on the reflector in the lower left quadrant of the shot. The upper left and top of the LED dome edge looks a little charred.

Looks like there's some heat damage to the reflector circular area just around the black plastic centering holder for the LED. In this shot the top right and top left corners of the LED die look a little burned.

I thought the reflector was aluminum in these Quarks, but is it coated plastic like a Maglite reflector? I've never taken the head apart before.

In retrospect, it seems impossible that the LED got hot enough to discolor a solid aluminum reflector without the LED itself melting into a puddle.

 

[Stress_Test]

Used a 60mm macro lens on a Canon T5i at work today to get these shots. Still a pain in the *** to get a decent shot. The camera lens was like an inch away from the flashlight lens and I had to get light in there at an angle with another flashlight.

Except in this shot where I just had the subject set in moonlight mode. There are a bunch of little specks of something on the dome. They could've been some kind of manufacturing debris, but I'm guessing they are part of the burned phosphor or something that was vaporizing from the heat. The top left area of the emitter looks a little darkened like it melted somewhat.

In this shot I noticed I could see two little trace wires running to the corners of the LED die itself (upper left/right). The upper left wire and area around it looks burned.

Man, macro shots can look neeto but they can be a real pain. I think next time I'm trying to do something like this at work in a serious capacity, I think I'll mount the subject item to one of our micrometer translation stages. Then I can move the target forward and back a thousandths at a time while watching the camera live-view to make sure I've got the area of focus bang-on.

 

[Got Lumens?]

I see your pain.
I have had the best success using a USB microscope to document up-close abnormalities.

Edit: You said You were using a 16650.
Which one?
Voltage might go low and increase ampacity upon the cell ??

Used a 60mm macro lens on a Canon T5i at work today to get these shots. Still a pain in the *** to get a decent shot. The camera lens was like an inch away from the flashlight lens and I had to get light in there at an angle with another flashlight.

Except in this shot where I just had the subject set in moonlight mode. There are a bunch of little specks of something on the dome. They could've been some kind of manufacturing debris, but I'm guessing they are part of the burned phosphor or something that was vaporizing from the heat. The top left area of the emitter looks a little darkened like it melted somewhat.
.....

Man, macro shots can look neeto but they can be a real pain. I think next time I'm trying to do something like this at work in a serious capacity, I think I'll mount the subject item to one of our micrometer translation stages. Then I can move the target forward and back a thousandths at a time while watching the camera live-view to make sure I've got the area of focus bang-on.

 

[Stress_Test]

I see your pain.
I have had the best success using a USB microscope to document up-close abnormalities.

Edit: You said You were using a 16650.
Which one?
Voltage might go low and increase ampacity upon the cell ??

It's an Orbtronic cell that's about a year old. Can't see how a battery could harm a light though, as long as the light can handle the input voltage (this is a 9 volt max Quark head)

Anyway, I know the cell is good, I've used it before and after and it checks out normal.