Smokin' hot Sipik SK73

LED Flashlights – General Info 18650 Flashlights
1

This Sipik is smokin’ hot! Really. Smoke comes out of the pill.

After it has been on for about a minute, I get some small — but definitely noticeable — tendrils of blue-white smoke curling out of the pill under the white plastic washer. Obviously smells electrical. I took the pill apart, and can see no evidence of anything burning. But then again, I only left it on for maybe a minute with smoke, three different times. Like all Sipiks, it got warm to the touch within just a couple minutes so I wonder if the thing would ever be useful. Can probably cook a breakfast on it like the sk98 after it has been on for five minutes.

Having a smoking flashlight that could short at any second — and short the mini-stick of potential dynamite that we call a lithium 18650 battery — did not seem like the world’s smartest idea.

So my question is this: Should I leave it on for a while (OUTSIDE IN A SAFE AREA) and see if whatever is burning just burns off? I’m thinking maybe the emitter has a big thumbprint on it or something else is heating up. Or should I just toss the driver and try another? I’m leaning toward the latter. It has AWFUL — just terrible — PWM so I would probably need to change the driver anyway, thankfully I just ordered two so not a super deal. It’s kinda a neat light for the 30 seconds I saw the beam before the smoke started. I just wonder how I could ever feel comfortable turning the thing on again, never knowing when it would start smoking again and blow my hand off.

So what would you guys do? Try again or pull the driver and call it a day? Then again, the smoke could be coming from the emitter and the driver change might do nothing.

It is this light:

http://www.manafont.com/product_info.php/sipik-sk73-cree-xml-t6-5mode-1600-lumen-floodtothrow-led-flashlight-black-18650-p-10721

Thanks for any advice you have.

2

Have you checked the heatsinking on it? If it isn't that then I would probably toss it.

3

>>>>>Have you checked the heatsinking on it?

Doesn’t appear to be any grease on the threads, if that’s what you mean. Just the usual crappy hollow alum pill with a white plastic washer holding the insides in.

4

I have a feeling that is the problem, you are cooking the LED because all the heat is trapped in the LED star.

5

>>>>>you are cooking the LED because all the heat is trapped in the LED star.

You know you could be right. I was thinking there was a TON of extra wire stuffed in the void between star and driver. I wonder if the star was not in contact with the pill “shelf?” Perhaps the 20 feet of extra wire pushed it up a bit off that ridge it’s supposed to contact. Maybe I’ll just wait for a new driver. Decisions. This is the third recent light with PWM out the yazoo. Very disappointed. Hope it’s not the wave of the future.

6

I would try and figure out whats smoking first.

I doubt its something “foreign” burning off the surface of the dome, or out-gassing from the XML itself. I have never seen that before with an LED, so I think its would be a rare occurrence. Letting stuff “burn off” is more an incan thing than an LED thing, so I don’t see the problem fixing itself.

Its also possible your +B spring is over-heating. I did that with my TR-J12, melted/smoked the thing. You’ll know this happens if your cells suddenly fits loose and rattles a lot, or your battery loses contact with the slightest shake/bump.

I am guessing the LED is generating enough heat, and the light is trapping it inside with no thermal path to the outside of the light. You have a small LED oven and its baking some of the soft parts inside. Stuff like plastic, wire insulation, heat shrink, O-ring gaskets… anything non-metal would be suspect.

I think you should just take it apart and see whats smoking. Note also that replacing the driver could make matters worse, if the new one pushes the LED at a higher current than the OEM driver.

7

>>>>>I think you should just take it apart and see whats smoking.

Already did that. That’s how I can see all the extra wire in the pill. Nothing I can see has any burned/singed areas. When troubleshooting computers during construction, the nose is mighty helpful for determining if anything isn’t right and where it’s coming from, but the area on the star/driver is just too small to smell if the smoke is coming from one component.

The only way I can see into the pill when firing up the light is to leave the white washer off, which will mean the star has NO contact with the flashlight to shunt heat away.

I’ll put it back together later today (too busy now with a stupid customer’s HTML emergency) and try to see if the smoke is indeed coming from LED self-nuking.

I have maybe five lights with very similar star/pill contact. They get hot, but don’t smoke certainly.

I don’t think it’s the spring because there’s no smoke in the batt compartment. Driver would act as a barrier and would trap the smoke in the batt compartment. But a good tip, one that I’ll remember.

I think it IS that the star was not in contact with the pill/light body. Extra wire is pushing it away.

I would think that smokin’ lights wouldn’t be that rare, but now I’m getting the feeling that it is a rare occurrence. Is it???

Thanks to everyone for their help.

8

When I first learned of power leds (about 2 years ago) I hooked a xp-e up to a 18650 direct drive without a heatsink and it started smoking after a couple minutes. I think that is what is happening.

Edit: Before it starts smoking does it turn angry blue?

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>>>>>Before it starts smoking does it turn angry blue?

No, it was just a normal looking bright t6 beam. But I think you’re right. Probably the star was not in contact with the pill/light body. I wish I could check it now. I hate it when jobs get in the way of important stuff. ;–0 Later this pm I will reassemble and fire er up…

10

I just ordered one of these about 2 weeks ago. I’ll report on how this works for me after I get mine. It’ll be my first XM-L flashlight. Currently my brightest is an Aurora SSC P7 C-bin also powered by a 18650, driven at 2.8A.

11

Just like everyone said, the star had pulled away from the pill so the only heat sink was the tiny little star, which she no work so good.

Wedged white ring back in, to hold the star in contact with the pill. It’s fine for a while. 10 minutes later, she’s a smokin’ hot again. AIEEEEE!!!

Then I get ANOTHER cheep mini zoomer tonight that’s doing the same thing. Smoking like a New Orleans BBQ contest. What?

If it was a static non-zoomer, the reseating would work forever, but this is afterall a zoomer, soo what happens is that as you zoom in, i.e., push the head in, you create air pressure BEHIND the star and then PLOOOP! The star unseats from the pill again and we get a BBQ.

Then as you zoom out, the air pressure goes the other way and reseats the star and no more smoke …… Until you zoom in again …. PLOOP! The star moves away from the pill, and it’s time to get out the ribs and throw ‘em on the smokin’ LED BBQ!

Sooooo. I takes my fujik heatsink compound and coat the inside of the pill, just around the edge where the star sits. Then I stick the star edge in the goop and use the white ring (hopefully) to hold the whole mess together while the fujik goop dries.

I am however concerned that I indeed have the real fujik GLUE or PASTE and not just the heatsink grease that never hardens, because the description on my fujik sure seems like grease not glue. Is this the right kind? Says type: silicone fluid, physical: greaselike, color: waite.

In any case, for now, it seems to be holding. These zoomers without a screw-in retention ring seem to be turning up more and more. Maybe someone has a better idea than me.

12

Welcome to the club, Metalophile!

13

Dang, I bought One Of These from ebay, it’s on the way now. Hope it doesn’t try to give itself lung cancer too!

14

Remember, the contact for heatsinking should be polished metal to polished metal — smoothest possible flat surfaces that match up.

The thermal material is supposed to fill the tiny little air gaps where the mating of the metal surfaces is imperfect.

No ‘thermal grease’ or ‘thermal glue’ works if you goop it on (as is likely done if it’s used at all, on cheap lights).

This is one way “budget” and “cheap” differ.

Think of the LED as a computer CPU. Same principle.

Chinese manufacturers — if you’d start doing this, making the heatsinking good — we’d pay you well for the better product you’d be making.

Budget — saves money.
Cheap — wastes money.

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>>>>>Hope it doesn’t try to give itself lung cancer too!

Nah, the light is the perfect size for a strip of bacon. Just lay it lengthwise on the light. You’ll have to use a toaster for toast though unless you have another sk73.

I did use the light all last night, and the heatsink grease is working just fine.

>>>>>>No ‘thermal grease’ or ‘thermal glue’ works if you goop it on

Well, it was gooped on at the beginning — knowing that mating the two metal pieces would squeeze any excess out — pretty much exactly like the approximately 8,000 CPUs I have greased and installed in my day. Now that the two pieces have been squeezed together and the excess wiped away, it has been de-gooped.

>>>>>Chinese manufacturers — if you’d start doing this, making the heatsinking good —
>>>>>>we’d pay you well for the better product you’d be making.

Ricght on. I mean, lets get one thing straight. I am playing with this light, trying to semi-recoup a bad investment but I will never trust this light. When ever I use this light, I will think the star has popped loose again and it will start smoking again. I should just toss it now. Of course, using a new star/driver does nothing because you’re still stuck with that horrible useless little white ring holding everything in.

Still would love to know if what I have is grease or glue. Does anyone know? Does anyone have fujik glue/cement? What does the tube say?

16

Good thing I ordered some thermal paste at the same time I ordered this light. Mine’s still not here yet. I think to some extent thermal paste itself might vacuum seal the two surfaces together. But y’all think a dab of super glue after I put a dab of paste between the star and the pill would help make sure it sticks? I tend to use high modes sparingly, so hopefully I won’t fry mine!

17

What kind of thermal “paste” did you get?

That star gets pretty darn hot, smokin’ hot in fact. :wink: I would think it would just melt the superglue. What’s the top working temp for superglue?

The low mode has PWM something awful.

18

I ordered SKU 37514 from DX. It’s described as “Adhesive Heatsink Plaster for PC Hard Parts (5g)”

Personally I don’t mind PWM so much. Or maybe it’s just that the 3 or 4 flashlights that I have with PWM low modes flash at such a fast rate that it’s not too noticeable in normal use. I like to shine my flashlights on low mode at the ceiling fans to see the effect :slight_smile: I have access to an oscilloscope at work. Maybe I’ll measure the PWM on my various flashlights to find out the frequencies in Hertz.

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>>>>>> I like to shine my flashlights on low mode at the ceiling fans to see the effect

Well, you’ll have fun with the low on this one then. Like a strobe light. Guaranteed headache in 15 minutes or less.

>>>>>>>>>I ordered SKU 37514 from DX. It’s described as “Adhesive Heatsink Plaster for PC Hard Parts (5g)”

Thank you!!! Just ordered some. I suspect the stuff I have is NOT any kind of glue. Just heatsink grease.

20

I generally avoid using superglue and CA adhesives on my lights. It out-gasses like crazy and can put a hazy residue, often times permanent (!!) on everything. It also becomes brittle and just cracks apart near boiling temperatures (175-200F). Its common knowledge in RC hobbies to unglue CA adhesives, boil your parts in water for a few minutes and then quench them in an ice water bath. Blot dry and split them apart with a knife edge and hammer. The impact will fracture and split the CA adhesive. This works most effectively with dollar store / drug store “super-glue” or “crazy glue”. Some of the better quality CAs are harder to get apart.